Magnetic core, rotary electric machine and brushless motor

Abstract

A magnetic core, a rotary electrical machine, and a brushless motor are provided. This magnetic core is used in a rotary electric machine, and is provided with: a core back; and a tooth portion including a tooth main body portion extending in a first direction from the core back portion and a tooth tip portion provided at a tip of the tooth main body portion in the first direction, the tooth tip portion being provided at a tip of the tooth main body portion in the first direction in a second direction that is a direction along a rotation axis of the rotating electrical machine when the magnetic core is assembled in the rotating electrical machine. The position of the geometric center of the tooth part is different from the position of the geometric center of the iron core back part.

Description

Technical Field

[0001] The present invention relates to a magnetic core used in a rotating electrical machine, a rotating electrical machine including the magnetic core, and a brushless motor including the magnetic core. Background Art

[0002] As an existing invention related to a magnetic core, for example, a magnetic core described in Patent Document 1 is known. The magnetic core described in Patent Document 1 includes: a tooth portion extending from the inner peripheral surface of a cylindrical yoke portion extending in the direction along the rotation axis toward the radial direction opposite to the yoke portion, or a tooth portion extending from the outer peripheral surface of a cylindrical yoke portion extending in the direction along the rotation axis toward the radial direction of the yoke portion. Here, the rotation axis is the rotation axis of the rotating electrical machine when the magnetic core is assembled in the rotating electrical machine. The tooth portion includes: a tooth body portion for winding a coil, and a tooth tip portion protruding in the direction along the rotation axis and in the circumferential direction of the yoke portion relative to the tooth body portion.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-060395

[0004] However, in the magnetic core described in Patent Document 1, it is desired to generate a thrust force in a direction along the rotation axis. Summary of the invention

[0005] Therefore, an object of the present invention is to provide a magnetic core, a rotary electric machine, and a brushless motor capable of generating a thrust in a direction along a rotation axis.

[0006] A magnetic core involved in one embodiment of the present invention is a magnetic core for a rotating electrical machine, comprising: an iron core back; and a tooth portion, which includes a tooth body portion extending from the above-mentioned iron core back in a first direction and a tooth end portion arranged at the end of the above-mentioned tooth body portion in the above-mentioned first direction, and in a second direction which becomes a direction along the rotation axis of the rotating electrical machine when the above-mentioned magnetic core is assembled in the above-mentioned rotating electrical machine, the position of the geometric center of the above-mentioned tooth portion is different from the position of the geometric center of the above-mentioned iron core back.

[0007] According to the present invention, it is possible to provide a magnetic core, a rotary electric machine, and a brushless motor capable of generating a thrust in a direction along a rotation axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a three-dimensional diagram of the magnetic core 1.

[0009] Figure 2 This is a cross-sectional view of the magnetic core 1 when viewed in the fourth direction DIR4.

[0010] Figure 3 1 is a perspective view of the appearance of a brushless motor 100 using the magnetic core 1 .

[0011] Figure 4 It is an exploded perspective schematic diagram of a brushless motor 100 using the magnetic core 1 .

[0012] Figure 5 This is a cross-sectional view of the magnetic core 6 according to the comparative example when viewed in the fourth direction DIR4.

[0013] Figure 6 This is a cross-sectional view of an example of magnetic forces F1 and F2 generated between the core 6 and the rotor member 22 according to the comparative example when the rotor 20 rotates, as viewed in the fourth direction DIR4.

[0014] Figure 7 This is a cross-sectional view showing an example of magnetic forces F1 and F2 generated between the core 1 and the rotor member 22 when the rotor 20 rotates, as viewed in the fourth direction DIR4.

[0015] Figure 8 This is a cross-sectional view of the magnetic core 1a when viewed in the fourth direction DIR4.

[0016] Fig. 9 It is a perspective view of the magnetic core 1b.

[0017] Fig.10 This is a cross-sectional view of the magnetic core 1b when viewed in the fourth direction DIR4.

[0018] Fig.11 This is a cross-sectional view of the magnetic core 1 b and the bus bar 40 when viewed in the fourth direction DIR4 .

[0019] Fig.12 It is a three-dimensional view of the magnetic core 1c.

[0020] Fig.13 This is a cross-sectional view of the magnetic core 1c when viewed in the fourth direction DIR4. DETAILED DESCRIPTION

[0021] [First embodiment]

[0022] (Structure of magnetic core 1)

[0023] Hereinafter, the structure of the magnetic core 1 according to the first embodiment of the present invention will be described with reference to the drawings. Figure 1 It is a three-dimensional diagram of the magnetic core 1. Figure 2 This is a cross-sectional view of the magnetic core 1 when viewed in the fourth direction DIR4.

[0024] In this specification, directions are defined as follows. The direction in which the tooth body portion 31 extends is defined as a first direction DIR1. The direction along the rotation axis of the brushless motor 100 when the magnetic core 1 is assembled in the brushless motor 100 is defined as a second direction DIR2. The orthographic projection of the first direction DIR1 onto a plane orthogonal to the second direction DIR2 is defined as a third direction DIR3. In the present embodiment, the third direction DIR3 is equal to the first direction DIR1. In addition, the direction orthogonal to the second direction DIR2 and the third direction DIR3 is defined as the fourth direction DIR4. In addition, in the present embodiment, since the third direction DIR3 is equal to the first direction DIR1, the fourth direction DIR4 is also orthogonal to the first direction DIR1. However, the first direction DIR1, the second direction DIR2, the third direction DIR3, and the fourth direction DIR4 are directions defined for the purpose of explanation. Therefore, the first direction DIR1 , the second direction DIR2 , the third direction DIR3 , and the fourth direction DIR4 of the magnetic core 1 when actually used may not necessarily coincide with the first direction DIR1 , the second direction DIR2 , the third direction DIR3 , and the fourth direction DIR4 of the present embodiment.

[0025] The core 1 is used for a brushless motor 100. The brushless motor 100 is an example of the "rotating electric machine" of the present invention.

[0026] like Figure 1 As shown, the magnetic core 1 includes a core back 2 and a tooth portion 3. The magnetic core 1 is a soft magnetic body. If a magnetic field is applied from the outside, the soft magnetic body is magnetized. Thereafter, if the application of the magnetic field is stopped, the soft magnetic body loses magnetization. The material of such a soft magnetic body is, for example, iron.

[0027] The magnetic core 1 is a molded body formed of soft magnetic powder. That is, the core back 2 and the tooth portion 3 are each a molded body formed of soft magnetic powder. The material of the soft magnetic powder includes, for example, iron and a binder. The binder is, for example, a resin. The soft magnetic powder is, for example, a material obtained by mixing iron powder and epoxy resin as an example of a binder. Such a magnetic core 1 is, for example, made by press molding. In addition, an insulation treatment is applied to the outer surface of the magnetic core 1.

[0028] like Figure 1 and Figure 2 As shown in FIG. 1 , the core back 2 has a first main surface S1 and a second main surface S2 arranged in the third direction DIR3. The second main surface S2 is located closer to the third direction DIR3 than the first main surface S1. Figure 1 As shown in FIG. 1 , when viewed in the third direction DIR3, the first main surface S1 and the second main surface S2 each have a rectangular shape. Figure 2As shown, the core back 2 has a geometric center GC2. The geometric center GC2 is the position of the arithmetic mean taken over all points belonging to the core back 2. In addition, the core back 2 has a shape that is plane-symmetrical with respect to a plane orthogonal to the second direction DIR2.

[0029] like Figure 1 As shown in FIG. 1 , the tooth portion 3 includes a tooth body portion 31 and a tooth tip portion 32. Figure 2 As shown, the tooth portion 3 has a geometric center GC3. The geometric center GC3 is the position of the arithmetic mean taken over all points belonging to the tooth portion 3. The tooth body portion 31 extends from the core back 2 to the first direction DIR1. In more detail, the tooth body portion 31 extends from the second main surface S2 to the first direction DIR1. In the present embodiment, the first direction DIR1 is orthogonal to the second direction DIR2. Therefore, the third direction DIR3 is equal to the first direction DIR1. In addition, the tooth body portion 31 is a rectangular parallelepiped. In addition, the tooth body portion 31 has a geometric center GC31. The geometric center GC31 is the position of the arithmetic mean taken over all points belonging to the tooth body portion 31. The tooth body portion 31 has a shape that is symmetrical with respect to a plane orthogonal to the second direction DIR2.

[0030] like Figure 1 As shown in FIG. 1 , the tooth body portion 31 has two ends in the second direction DIR2, namely, a first end E1 and a second end E2. The first end E1 is located closer to the second direction DIR2 than the second end E2. Figure 3 and Figure 4 As shown in FIG. 1 , the second direction DIR2 is a direction along the rotation axis of the brushless motor 100 when the core 1 is assembled in the brushless motor 100 .

[0031] like Figure 1 and Figure 2 As shown in FIG. 1 , the tooth end portion 32 has a third main surface S3 and a fourth main surface S4 arranged in the third direction DIR3. The fourth main surface S4 is located closer to the third direction DIR3 than the third main surface S3. Figure 1 As shown in FIG. 1 , the third main surface S3 and the fourth main surface S4 each have a rectangular shape. Figure 2 As shown, the tooth end portion 32 has a geometric center GC32. The geometric center GC32 is a position of the arithmetic mean taken over all points belonging to the tooth end portion 32. In addition, the tooth end portion 32 has a shape that is plane-symmetrical with respect to a plane orthogonal to the second direction DIR2.

[0032] In addition, if Figure 1 As shown, the tooth end portion 32 has two ends in the second direction DIR2, namely, a third end E3 and a fourth end E4. The third end E3 is located closer to the second direction DIR2 than the fourth end E4. Figure 1As shown, such a tooth terminal portion 32 is provided at the terminal end of the tooth main body portion 31 in the first direction DIR1.

[0033] like Figure 1 As shown, the outer edge O2 of the core back 2 observed in the third direction DIR3 surrounds the outer edge O31 of the tooth body 31 observed in the third direction DIR3. In addition, the outer edge O32 of the tooth tip 32 observed in the third direction DIR3 surrounds the outer edge O31 of the tooth body 31 observed in the third direction DIR3. In addition, as Figure 2 As shown, in the third direction DIR3 , the length of the tooth body portion 31 in the second direction DIR2 is uniform.

[0034] In this embodiment, if Figure 2 As shown, the distance D1 between the first end E1 of the tooth body 31 and the geometric center GC2 of the core back 2 in the second direction DIR2 is equal to the distance D2 between the second end E2 of the tooth body 31 and the geometric center GC2 of the core back 2 in the second direction DIR2. Accordingly, the position PGC31 of the geometric center GC31 of the tooth body 31 in the second direction DIR2 is equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2.

[0035] On the other hand, Figure 2 As shown, the distance D3 between the third end E3 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2 is smaller than the distance D4 between the fourth end E4 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2. Accordingly, the geometric center GC2 of the core back 2 is located closer to the second direction DIR2 than the geometric center GC32 of the tooth end portion 32. That is, the position PGC32 of the geometric center GC32 of the tooth end portion 32 in the second direction DIR2 is different from the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2. As a result, the geometric center GC2 of the core back 2 is located closer to the second direction DIR2 than the geometric center GC3 of the tooth portion 3. That is, in the second direction DIR2, the position PGC3 of the geometric center GC3 of the tooth portion 3 is different from the position PGC2 of the geometric center GC2 of the core back 2. More specifically, the geometric center GC2 of the core back 2 is located closer to the second direction DIR2 than the geometric center GC3 of the tooth portion 3. Therefore, the magnetic core 1 does not have a symmetrical shape with respect to a plane perpendicular to the second direction DIR2. In addition, the magnetic core 1 has a symmetrical shape with respect to a plane perpendicular to the fourth direction DIR4.

[0036] Here, a line connecting the geometric centers of the cross sections of the tooth body 31 perpendicular to the third direction DIR3 is defined as the first line L1. The geometric center of the cross section of the tooth body 31 perpendicular to the third direction DIR3 is the position of the arithmetic mean of all points of the cross section perpendicular to the third direction DIR3 belonging to the tooth body 31. Figure 2 As shown, the first line L1 is a straight line. In addition, in the present embodiment, the direction in which the first line L1 extends is parallel to the third direction DIR3 and is orthogonal to the second direction DIR2. That is, the position of the first line L1 at the end of the tooth body 31 in the first direction DIR1 and the position of the first line L1 at the end of the tooth body 31 on the opposite side of the end are equal in the second direction DIR2.

[0037] (Structure of Brushless Motor 100)

[0038] Hereinafter, the structure of the brushless motor 100 according to the first embodiment of the present invention will be described with reference to the drawings. Figure 3 1 is a perspective view of the appearance of a brushless motor 100 using the magnetic core 1 . Figure 4 1 is an exploded perspective schematic diagram of a brushless motor 100 using the magnetic core 1. Figure 4 In the drawings, only representative magnetic cores 1 , coils 13 , and insulating members 14 among the plurality of magnetic cores 1 , the plurality of coils 13 , and the plurality of insulating members 14 are denoted by reference numerals.

[0039] like Figure 4 As shown, the brushless motor 100 includes a rotor 20 and a stator assembly 10. Figure 4 As shown, when viewed in the second direction DIR2, the stator assembly 10 is disposed around the rotor 20. That is, the brushless motor 100 is an inner rotor type.

[0040] like Figure 4 As shown, the rotor 20 includes a shaft body 21 and a rotor member 22. The shaft body 21 has a shape extending in the second direction DIR2. In more detail, the shaft body 21 is cylindrical. The rotor member 22 is cylindrical. The central axis of each of the shaft body 21 and the rotor member 22 is the Z axis. That is, the rotation axis of the brushless motor 100 is the Z axis. Therefore, the second direction DIR2 is a direction along the Z axis.

[0041] like Figure 4As shown, the rotor component 22 includes a soft magnetic body 23 and a hard magnetic body 24. The rotor component 22 is mounted on the outer peripheral surface of the shaft body 21 in the radial direction with the Z axis as the center. In more detail, the soft magnetic body 23 is mounted on the outer peripheral surface of the shaft body 21 in the radial direction with the Z axis as the center. The hard magnetic body 24 is mounted on the outer peripheral surface of the soft magnetic body 23 in the radial direction with the Z axis as the center. In addition, the rotor component 22 is configured so that the position PGC22 of the geometric center GC22 of the rotor component 22 in the second direction DIR2 is equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2. In addition, the geometric center GC22 is the position of the arithmetic mean taken over all points belonging to the rotor component 22.

[0042] The soft magnetic body 23 is a soft magnetic body. In addition, the hard magnetic body 24 is a hard magnetic body. If a magnetic field is applied from the outside, the hard magnetic body is magnetized. Thereafter, even if the application of the magnetic field is stopped, the hard magnetic body does not lose its magnetization. The material of such a hard magnetic body is a magnet.

[0043] like Figure 4 As shown, the stator assembly 10 includes a bearing 11, a housing 12, a plurality of cores 1, a plurality of coils 13, and a plurality of insulating members 14. That is, the brushless motor 100 includes the core 1.

[0044] The bearing 11 supports the shaft body 21 so that it can rotate around the Z axis. Figure 4 As shown, the bearing 11 has a first bearing 11a and a second bearing 11b. The first bearing 11a and the second bearing 11b are each, for example, a ball bearing. The first bearing 11a and the second bearing 11b are each cylindrical. The center axis of each of the first bearing 11a and the second bearing 11b is the Z axis. That is, the center axis of each of the first bearing 11a and the second bearing 11b is consistent with the center axis of the shaft body 21.

[0045] like Figure 4 As shown, the first bearing 11a is located closer to the second direction DIR2 than the second bearing 11b. In addition, the first bearing 11a is located closer to the second direction DIR2 than the rotor member 22. The second bearing 11b is located in the opposite direction of the second direction DIR2 than the rotor member 22. The second bearing 11b supports the end of the shaft body 21 in the opposite direction of the second direction DIR2.

[0046] like Figure 3 As shown in FIG. 1 , the housing 12 includes a first housing 12a and a second housing 12b. Figure 3 and Figure 4As shown, the first housing 12a is cylindrical. The central axis of the first housing 12a is the Z axis. The first housing 12a is located closer to the second direction DIR2 than the second housing 12b. In addition, the first housing 12a has an opening OP. Thus, the end of the shaft body 21 in the second direction DIR2 protrudes from the opening OP in the second direction DIR2. That is, the brushless motor 100 is a single-axis type.

[0047] The first housing 12a supports the first bearing 11a, the plurality of magnetic cores 1, the plurality of coils 13, and the plurality of insulating members 14. The second housing 12b supports the second bearing 11b. The first housing 12a and the second housing 12b are each made of a highly rigid material such as SUS.

[0048] The number of each of the plurality of magnetic cores 1, the plurality of coils 13 and the plurality of insulating members 14 is 9. Each of the 9 coils 13 and the 9 insulating members 14 is respectively provided corresponding to each of the 9 magnetic cores 1. In more detail, if a group including a magnetic core 1, a coil 13 and an insulating member 14 is regarded as a set, the 9 sets are arranged in a circumferential direction centered on the Z axis. Each set is arranged around the hard magnetic body 24 at intervals from the hard magnetic body 24. In addition, the structure of each set is the same. Therefore, a set including a magnetic core 1, a coil 13 and an insulating member 14 is described.

[0049] The core 1 is magnetized by the magnetic field generated by the hard magnetic body 24 and the magnetic field generated by the coil 13. As a result, the core 1 generates a magnetic force that rotates the rotor. Figure 4 As shown, there is a gap (air gap) between the core 1 and the rotor member 22. In the present embodiment, the first direction DIR1 is a direction toward the rotation axis of the brushless motor 100 when the core 1 is assembled in the brushless motor 100.

[0050] like Figure 4 As shown, when viewed in the radial direction with the Z axis as the center, the coil 13 is located around the magnetic core 1 and is wound around the tooth body 31. The coil 13 is made of a conductive material such as copper. In addition, the coil 13 has a structure in which the surface of the copper wire is covered with an insulating film. The coil 13 generates a magnetic field by flowing an electric current in the coil 13.

[0051] The insulating member 14 is an insulator. Figure 4 As shown, the insulating member 14 is arranged between the magnetic core 1 and the coil 13. Thus, the magnetic core 1 and the coil 13 are electrically insulated. In the present embodiment, the insulating member 14 is in the form of a film, but it may also be in the form of a sheet. In addition, it may also be that the insulating member 14 is arranged so that a part of the insulating member 14 is arranged between the magnetic core 1 and the coil 13. Therefore, it may also be that the insulating member 14 is arranged on the entire surface of the coil 13.

[0052] A current is supplied from a power source (not shown) to the coil 13. The rotation of the rotor 20 is controlled by controlling the current.

[0053] [Effect]

[0054] According to the magnetic core 1, a thrust force can be generated in the direction along the rotation axis. The principle of generating a thrust force in the direction along the rotation axis will be described with reference to the drawings. Figure 5 It is a cross-sectional view of the magnetic core 6 according to the comparative example as viewed in the fourth direction DIR4. Figure 6 This is a cross-sectional view of an example of magnetic forces F1 and F2 generated between the core 6 and the rotor member 22 according to the comparative example when the rotor 20 is rotating, as viewed in the fourth direction DIR4. Figure 7 This is a cross-sectional view showing an example of magnetic forces F1 and F2 generated between the core 1 and the rotor member 22 when the rotor 20 is rotating, as viewed in the fourth direction DIR4.

[0055] First, the magnetic core 6 involved in the comparative example will be described. In addition, for the magnetic core 6 involved in the comparative example, only the parts that are different from the magnetic core 1 will be described, and the rest will be omitted. Figure 5 As shown, in the magnetic core 6 involved in the comparative example, the distance D3 between the third end E3 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2 is equal to the distance D4 between the fourth end E4 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2. Accordingly, the position PGC32 of the geometric center GC32 of the tooth end portion 32 in the second direction DIR2 is equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2. The position PGC31 of the geometric center GC31 of the tooth body 31 in the second direction DIR2 and the position PGC32 of the geometric center GC32 of the tooth tip 32 in the second direction DIR2 are respectively equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2, and thus the position PGC3 of the geometric center GC3 of the tooth 3 in the second direction DIR2 is equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2. As a result, the position PGC6 of the geometric center GC6 of the magnetic core 6 involved in the comparative example in the second direction DIR2 becomes equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2. In addition, the magnetic core 6 involved in the comparative example has a symmetrical shape with respect to a plane orthogonal to the second direction DIR2.

[0056] When the rotor 20 is rotating, Figure 6As shown, magnetic forces F1 and F2 are generated between the magnetic core 6 involved in the comparative example and the rotor component 22. The magnetic forces F1 and F2 are Coulomb forces acting between two magnetic charges. On the one hand, when the magnetic poles of the magnetic core 6 involved in the comparative example and the magnetic poles of the surface of the rotor component 22 facing the opposite direction of the third direction DIR3 are different from each other, the direction of the magnetic force F1 is the third direction DIR3. On the other hand, when the magnetic poles of the magnetic core 6 involved in the comparative example and the magnetic poles of the surface of the rotor component 22 facing the opposite direction of the third direction DIR3 are the same as each other, the direction of the magnetic force F1 is the opposite direction of the third direction DIR3. In any case, the direction of the magnetic force F1 is parallel to the third direction DIR3. That is, the direction of the magnetic force F1 is orthogonal to the second direction DIR2. Therefore, in the magnetic core 6 involved in the comparative example, no thrust is generated in the direction along the axis of rotation.

[0057] For the magnetic core 1, in the second direction DIR2, the position PGC3 of the geometric center GC3 of the tooth portion 3 is different from the position PGC2 of the geometric center GC2 of the core back 2. Therefore, the position PGC22 of the geometric center GC22 of the rotor component 22 in the second direction DIR2 is different from the position PGC1 of the geometric center GC1 of the magnetic core 1 in the second direction DIR2. Therefore, the direction of the magnetic force F1 and the direction of the magnetic force F2 are not parallel to the third direction DIR3. In more detail, as Figure 7 As shown, the direction of the magnetic force F1 is parallel to the straight line connecting the geometric center GC22 of the rotor component 22 and the geometric center GC1 of the magnetic core 1. In the case of the present embodiment, the geometric center GC22 of the rotor component 22 is located closer to the second direction DIR2 than the geometric center GC1 of the magnetic core 1. Therefore, in the case where the magnetic poles of the magnetic core 1 and the magnetic poles of the surface of the rotor component 22 facing the opposite direction of the third direction DIR3 are different from each other, the magnetic force F1 includes a component in the second direction DIR2. On the other hand, in the case where the magnetic poles of the magnetic core 1 and the magnetic poles of the surface of the rotor component 22 facing the opposite direction of the third direction DIR3 are the same, the magnetic force F1 includes a component in the opposite direction of the second direction DIR2. In any case, the magnetic force F1 includes a component in the direction along the axis of rotation (the second direction DIR2 or the opposite direction of the second direction DIR2). Therefore, according to the magnetic core 1, a thrust in the direction along the axis of rotation can be generated.

[0058] According to the magnetic core 1, the thrust in the direction along the axis of rotation can be increased. In more detail, the Coulomb force is inversely proportional to the square of the distance between the two magnetic charges. In addition, the magnetic force F1 and the magnetic force F2 are the resultant forces of the Coulomb force acting between the rotor component 22 and the tooth end portion 32, the Coulomb force acting between the rotor component 22 and the tooth main body portion 31, and the Coulomb force acting between the rotor component 22 and the core back 2. Here, when the magnetic core 1 is assembled in the brushless motor 100, the tooth end portion 32 is arranged at the position closest to the rotor component 22 among the core back 2, the tooth main body portion 31 and the tooth end portion 32. Therefore, according to the magnetic core 1, the position PGC32 of the geometric center GC32 of the tooth end portion 32 in the second direction DIR2 is different from the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2. Therefore, according to the magnetic core 1, the thrust in the direction along the axis of rotation can be increased.

[0059] According to the magnetic core 1, it is possible to ensure a region that overlaps with the tooth end portion 32 when viewed in the second direction DIR2, that is, a region that is located closer to the tooth end portion 32 in the second direction DIR2. More specifically, the distance D3 between the third end E3 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2 is smaller than the distance D4 between the fourth end E4 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2. Therefore, it is possible to make the region that overlaps with the tooth end portion 32 when viewed in the second direction DIR2, that is, a region that is located closer to the tooth end portion 32 in the second direction DIR2, larger than the region that overlaps with the tooth end portion 32 when viewed in the second direction DIR2, that is, a region that is located in the opposite direction of the tooth end portion 32 in the second direction DIR2. Therefore, according to the magnetic core 1, it is possible to ensure a region that overlaps with the tooth end portion 32 when viewed in the second direction DIR2, that is, a region that is located closer to the tooth end portion 32 in the second direction DIR2 than the tooth end portion 32.

[0060] According to the magnetic core 1, the coil 13 can be easily wound around the tooth body portion 31. More specifically, the position of the first line L1 at the end of the tooth body portion 31 in the first direction DIR1 and the position of the first line L1 at the end of the tooth body portion 31 on the opposite side of the end are equal in the second direction DIR2. That is, the direction in which the first line L1 extends is orthogonal to the second direction DIR2, which is the direction along the rotation axis of the brushless motor 100. Therefore, according to the magnetic core 1, the coil 13 can be easily wound around the tooth body portion 31.

[0061] According to the magnetic core 1, the magnetic core 1 can be easily formed. More specifically, the core back 2, the tooth body 31, and the tooth end 32 each have a shape symmetrical with respect to a plane perpendicular to the second direction DIR2. Therefore, for example, in the case where the magnetic core 1 is manufactured by press forming, the magnetic core 1 can be manufactured by using a mold and a punch each having a shape symmetrical with respect to a plane perpendicular to the second direction DIR2. As a result, according to the magnetic core 1, the magnetic core 1 can be easily formed.

[0062] [Second embodiment]

[0063] Hereinafter, a magnetic core 1 a according to a second embodiment of the present invention will be described with reference to the drawings. Figure 8 It is a cross-sectional view of the magnetic core 1a viewed in the fourth direction DIR4. In addition, regarding the magnetic core 1a according to the second embodiment, only the portion different from the magnetic core 1 according to the first embodiment will be described, and the remaining portion will be omitted.

[0064] like Figure 8 As shown, the magnetic core 1a is different from the magnetic core 1 in that the position PGC32 of the geometric center GC32 of the tooth end portion 32 in the second direction DIR2 is equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2, and the position PGC31 of the geometric center GC31 of the tooth body portion 31 in the second direction DIR2 is different from the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2.

[0065] More specifically, in this embodiment, if Figure 8 As shown, the distance D3 between the third end E3 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2 is equal to the distance D4 between the fourth end E4 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2. Accordingly, the position PGC32 of the geometric center GC32 of the tooth end portion 32 in the second direction DIR2 is equal to the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2.

[0066] On the other hand, Figure 8As shown, the distance D1 between the first end E1 of the tooth body 31 and the geometric center GC2 of the core back 2 in the second direction DIR2 is smaller than the distance D2 between the second end E2 of the tooth body 31 and the geometric center GC2 of the core back 2 in the second direction DIR2. Accordingly, the geometric center GC2 of the core back 2 is located closer to the second direction DIR2 than the geometric center GC31 of the tooth body 31. As a result, the geometric center GC2 of the core back 2 is located closer to the second direction DIR2 than the geometric center GC3 of the tooth 3. That is, in the second direction DIR2, the position PGC3 of the geometric center GC3 of the tooth 3 is different from the position PGC2 of the geometric center GC2 of the core back 2.

[0067] In the magnetic core 1a as described above, the same effect as that of the magnetic core 1 is achieved. In addition, according to the magnetic core 1a, it is possible to ensure a region that overlaps with the tooth body portion 31 when viewed in the second direction DIR2, that is, a region that is located closer to the tooth body portion 31 in the second direction DIR2. More specifically, the distance D1 between the first end E1 of the tooth body portion 31 and the geometric center GC2 of the core back 2 in the second direction DIR2 is smaller than the distance D2 between the second end E2 of the tooth body portion 31 and the geometric center GC2 of the core back 2 in the second direction DIR2. Therefore, it is possible to make the region that overlaps with the tooth body portion 31 when viewed in the second direction DIR2, that is, a region that is located closer to the tooth body portion 31 in the second direction DIR2, larger than the region that overlaps with the tooth body portion 31 when viewed in the second direction DIR2, that is, a region that is located in the opposite direction of the tooth body portion 31 in the second direction DIR2. Thus, according to the magnetic core 1 a , it is possible to secure a region overlapping with the tooth body portion 31 when viewed in the second direction DIR2 , that is, a region located closer to the tooth body portion 31 in the second direction DIR2 .

[0068] [Third embodiment]

[0069] Hereinafter, a magnetic core 1 b according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 9 It is a perspective view of the magnetic core 1b. Fig.10 This is a cross-sectional view of the magnetic core 1b when viewed in the fourth direction DIR4. Fig.11 It is a cross-sectional view of the magnetic core 1b and the bus bar 40 as viewed in the fourth direction DIR4. In addition, only the parts of the magnetic core 1b according to the third embodiment that are different from the magnetic core 1 according to the first embodiment will be described, and the rest will be omitted.

[0070] like Fig. 9 and Fig.10As shown in FIG. 1 , the core 1 b is different from the core 1 in that the first direction DIR1 is not orthogonal to the second direction DIR2 . That is, in the present embodiment, the third direction DIR3 is different from the first direction DIR1 .

[0071] like Fig.10 As shown, the position of the first line L1 at the end of the tooth body portion 31 in the first direction DIR1 is offset from the position of the first line L1 at the end of the tooth body portion 31 on the opposite side to the end in the second direction DIR2. Therefore, the tooth body portion 31 is in the shape of a quadrangular prism. More specifically, in the present embodiment, the first line L1 at the end of the tooth body portion 31 in the first direction DIR1 is located in the opposite direction of the second direction DIR2 than the first line L1 at the end of the tooth body portion 31 on the opposite side to the end of the tooth body portion 31 in the first direction DIR1. Therefore, in the present embodiment, the tooth body portion 31 does not have a symmetrical shape with respect to a plane orthogonal to the second direction DIR2.

[0072] In the magnetic core 1b as described above, the same effect as that of the magnetic core 1 is achieved. In addition, according to the magnetic core 1b, it is possible to ensure a region that overlaps with the end portion of the tooth body portion 31 in the first direction DIR1 when viewed in the second direction DIR2, that is, a region that is located closer to the second direction DIR2 than the end portion of the tooth body portion 31 in the first direction DIR1 or in the opposite direction to the second direction DIR2. More specifically, the position of the first line L1 at the end portion of the tooth body portion 31 in the first direction DIR1 and the position of the first line L1 at the end portion of the tooth body portion 31 on the opposite side to the end portion are offset in the second direction DIR2. In the present embodiment, the first line L1 at the end portion of the tooth body portion 31 in the first direction DIR1 is located in the opposite direction to the second direction DIR2 than the first line L1 at the end portion of the tooth body portion 31 on the opposite side to the end portion of the tooth body portion 31 in the first direction DIR1. Thus, according to the magnetic core 1b, when viewed in the second direction DIR2, a region overlapping with the end portion of the tooth body portion 31 in the first direction DIR1, that is, a region located closer to the tooth body portion 31 in the second direction DIR2 in the first direction DIR1 can be ensured. Fig.11 As shown, the wiring members such as the bus bar 40 can be arranged in an area overlapping with the end portion of the tooth body portion 31 in the first direction DIR1 when viewed in the second direction DIR2, that is, an area located closer to the second direction DIR2 than the end portion of the tooth body portion 31 in the first direction DIR1. As a result, the length of the brushless motor 100 in the second direction DIR2 can be shortened, and the brushless motor 100 can be made low-profile and small-sized.

[0073] [First Modification]

[0074] Hereinafter, a magnetic core 1c according to a first modified example of the present invention will be described with reference to the drawings. Fig.12 It is a three-dimensional view of the magnetic core 1c. Fig.13 It is a cross-sectional view of the magnetic core 1c viewed in the fourth direction DIR4. In addition, only the parts of the magnetic core 1c according to the first modification example that are different from the magnetic core 1b according to the third embodiment will be described, and the rest will be omitted.

[0075] like Fig.12 and Fig.13 As shown, the core 1c is different from the core 1b in that the first line L1 is a broken line.

[0076] The magnetic core 1c described above also exhibits the same effects as those of the magnetic core 1b.

[0077] [Other embodiments]

[0078] The magnetic core according to the present invention is not limited to the magnetic cores 1 and 1a to 1c, and can be modified within the scope of the gist thereof. In addition, the structures of the magnetic cores 1 and 1a to 1c can be arbitrarily combined.

[0079] In addition, the first direction DIR1 may be orthogonal to the second direction DIR2 or may not be orthogonal to the second direction DIR2.

[0080] The rotary electric machine may have a structure that rotates the rotor by electricity or a structure that generates electricity by the rotation of the rotor. In this case, the rotary electric machine may include at least one of the cores 1 and 1a to 1c, and may have a brush.

[0081] In addition, the magnetic cores 1 and 1a to 1c may be produced by laminating electromagnetic steel sheets. The magnetic cores 1 and 1a to 1c may be made of a soft magnetic material.

[0082] In addition, the outer surfaces of the magnetic cores 1 and 1a to 1c may not be subjected to insulation treatment.

[0083] Furthermore, when viewed in the third direction DIR3 , each of the first main surface S1 and the second main surface S2 of the core back 2 may not have a rectangular shape.

[0084] In addition, the core back 2 may not have a shape that is plane-symmetrical with respect to a plane perpendicular to the second direction DIR2.

[0085] In addition, the tooth body portion 31 may not be in the shape of a rectangular parallelepiped or a quadrangular prism.

[0086] Furthermore, each of the third main surface S3 and the fourth main surface S4 of the tooth tip portion 32 may not have a rectangular shape when viewed in the third direction DIR3.

[0087] In addition, the tooth tip portion 32 may not have a shape that is plane-symmetrical with respect to a plane perpendicular to the second direction DIR2.

[0088] In addition, the outer edge O2 of the core back 2 observed in the third direction DIR3 may not surround the outer edge O31 of the tooth body 31 observed in the third direction DIR3. In addition, the outer edge O32 of the tooth tip 32 observed in the third direction DIR3 may not surround the outer edge O31 of the tooth body 31 observed in the third direction DIR3.

[0089] Furthermore, in the third direction DIR3 , the length of the tooth body portion 31 in the second direction DIR2 as viewed in the fourth direction DIR4 may not be uniform.

[0090] In addition, in the magnetic core 1, the distance D1 between the first end E1 of the tooth body portion 31 and the geometric center GC2 of the core back 2 in the second direction DIR2 is different from the distance D2 between the second end E2 of the tooth body portion 31 and the geometric center GC2 of the core back 2 in the second direction DIR2. In addition, in the magnetic core 1, the position PGC31 of the geometric center GC31 of the tooth body portion 31 in the second direction DIR2 is different from the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2.

[0091] In addition, in the magnetic core 1a, the distance D3 between the third end E3 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2 may be different from the distance D4 between the fourth end E4 of the tooth end portion 32 and the geometric center GC2 of the core back 2 in the second direction DIR2. In addition, in the magnetic core 1a, the position PGC32 of the geometric center GC32 of the tooth end portion 32 in the second direction DIR2 may be different from the position PGC2 of the geometric center GC2 of the core back 2 in the second direction DIR2.

[0092] In addition, the core 1 may not have a shape that is plane-symmetrical with respect to a plane perpendicular to the fourth direction DIR4.

[0093] In addition, the first line L1 is not limited to a straight line or a broken line, and may be a curved line. In addition, the first line L1 may include a straight line or a curved line.

[0094] In addition, in the magnetic core 1b, the first line L1 at the end of the tooth body portion 31 in the first direction DIR1 may be located closer to the second direction DIR2 than the first line L1 at the end of the tooth body portion 31 on the opposite side to the end of the tooth body portion 31 in the first direction DIR1. In this case, it is possible to ensure a region that overlaps with the end of the tooth body portion 31 in the first direction DIR1 when viewed in the second direction DIR2 and is located in the first direction DIR1 in the opposite direction to the tooth body portion 31 in the second direction DIR2.

[0095] In addition, the brushless motor 100 may be an outer rotor type. In this case, the first direction DIR1 is the opposite direction to the direction toward the rotation axis of the brushless motor 100 when the core 1 is assembled in the brushless motor 100 .

[0096] In addition, the brushless motor 100 is not limited to a single-shaft type, and the brushless motor 100 may be a dual-shaft type, for example.

[0097] In addition, in the brushless motor 100 , the first bearing 11 a and the second bearing 11 b may be pressurized by the thrust force generated in the direction along the rotation axis.

[0098] In addition, each of the first bearing 11 a and the second bearing 11 b is not limited to a ball bearing.

[0099] In addition, the material of each of the first housing 12a and the second housing 12b may be a material having high rigidity.

[0100] The number of the plurality of magnetic cores 1 , the plurality of coils 13 , and the plurality of insulating members 14 is not limited to 9. Each of the plurality of coils 13 and each of the plurality of insulating members 14 may be provided corresponding to each of the plurality of magnetic cores 1 .

[0101] The present invention has the following structure.

[0102] (1) A magnetic core is a magnetic core for a rotating electrical machine, comprising: an iron core back; and a tooth portion, which includes a tooth body portion extending from the above-mentioned iron core back in a first direction and a tooth terminal portion provided at the terminal of the above-mentioned tooth body portion in the above-mentioned first direction, wherein the position of the geometric center of the above-mentioned tooth portion is different from the position of the geometric center of the above-mentioned iron core back in a second direction which is a direction along the rotation axis of the rotating electrical machine when the above-mentioned magnetic core is assembled in the above-mentioned rotating electrical machine.

[0103] (2) In the magnetic core described in (1), a position of a geometric center of the tooth body portion in the second direction is different from a position of a geometric center of the core back portion in the second direction.

[0104] (3) In the magnetic core described in (1) or (2), the position of the geometric center of the tooth tip portion in the second direction is different from the position of the geometric center of the core back in the second direction.

[0105] (4) In the magnetic core described in any one of (1) to (3), the tooth main body has two ends in the second direction, namely a first end and a second end, and the distance between the first end and the geometric center of the back of the core in the second direction is smaller than the distance between the second end and the geometric center of the back of the core in the second direction.

[0106] (5) In the magnetic core described in any one of (1) to (4), the tooth end portion has two ends in the second direction, namely, a third end and a fourth end, and the distance between the third end and the geometric center of the core back in the second direction is smaller than the distance between the fourth end and the geometric center of the core back in the second direction.

[0107] (6) In the magnetic core described in any one of (1) to (5), the orthographic projection of the first direction onto a plane perpendicular to the second direction is defined as the third direction, and the line connecting the geometric centers of the cross sections of the tooth body portion perpendicular to the third direction is defined as the first line, and the first line is a straight line, and the position of the first line at the terminal portion of the tooth body portion and the position of the first line at the end portion of the tooth body portion on the opposite side of the terminal portion in the second direction are equal.

[0108] (7) In the magnetic core described in any one of (1) to (5), the orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as the third direction, and the line connecting the geometric centers of the cross sections of the tooth body portion that are perpendicular to the third direction is defined as the first line, and the first line is a straight line, and the position of the first line at the terminal portion of the tooth body portion and the position of the first line at the end portion of the tooth body portion on the opposite side of the terminal portion are offset in the second direction.

[0109] (8) In the magnetic core described in any one of (1) to (5), the orthographic projection of the first direction onto a plane perpendicular to the second direction is defined as the third direction, and the line connecting the geometric centers of the cross sections of the tooth body portion perpendicular to the third direction is defined as the first line, and the first line is a broken line, and the position of the first line at the terminal portion of the tooth body portion and the position of the first line at the end portion of the tooth body portion on the opposite side of the terminal portion are offset in the second direction.

[0110] (9) In the magnetic core described in any one of (1) to (6), the orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as a third direction, the core back has a shape symmetrical with respect to the plane orthogonal to the second direction, the tooth body has a shape symmetrical with respect to the plane orthogonal to the second direction, and the tooth tip has a shape symmetrical with respect to the plane orthogonal to the second direction.

[0111] (10) In the magnetic core described in any one of (1) to (9), the orthographic projection obtained by projecting the above-mentioned first direction onto a plane orthogonal to the above-mentioned second direction is defined as a third direction, and in the above-mentioned third direction, the length of the above-mentioned tooth main body in the above-mentioned second direction is uniform.

[0112] (11) In the magnetic core described in any one of (1) to (10), each of the core back and the teeth is a molded body formed of soft magnetic powder.

[0113] (12) In the magnetic core described in (11), the material of the soft magnetic powder includes iron and resin.

[0114] (13) A rotating electrical machine comprising the magnetic core described in any one of (1) to (12).

[0115] (14) A brushless motor comprising the magnetic core described in any one of (1) to (12).

[0116] Description of Reference Numerals

[0117] 1, 1a, 1b, 1c, 6... magnetic core; 2... back of the core; 3... tooth; 10... stator assembly; 11... bearing; 11a... first bearing; 11b... second bearing; 12... housing; 12a... first housing; 12b... second housing; 13... coil; 14... insulating member; 20... rotor; 21... shaft; 22... rotor member; 23... soft magnetic body; 24... hard magnetic body; 31... tooth body; 32... tooth end; 40... bus bar; 100... brushless motor; D 1, D2, D3, D4...distance; DIR1...1st direction; DIR2...2nd direction; DIR3...3rd direction; DIR4...4th direction; E1...1st end; E2...2nd end; E3...3rd end; E4...4th end; GC1, GC2, GC3, GC6, GC22, GC31, GC32...geometric center; L1...1st line; O2, O31, O32...outer edge; OP...opening; S1...1st principal surface; S2...2nd principal surface; S3...3rd principal surface; S4...4th principal surface.

Claims

1. A magnetic core used for a rotating electrical machine, characterized in that: have: Core back; and a tooth portion including a tooth body portion extending from the core back in a first direction and a tooth terminal portion provided at a terminal of the tooth body portion in the first direction, In a second direction that is a direction along a rotation axis of the rotating electrical machine when the magnetic core is assembled in the rotating electrical machine, a position of a geometric center of the tooth portion is different from a position of a geometric center of the core back.

2. The magnetic core according to claim 1, characterized in that A position of a geometric center of the tooth body portion in the second direction is different from a position of a geometric center of the core back in the second direction.

3. The magnetic core according to claim 1 or 2, characterized in that: A position of a geometric center of the tooth tip portion in the second direction is different from a position of a geometric center of the core back in the second direction.

4. The magnetic core according to any one of claims 1 to 3, characterized in that: The tooth body has two ends in the second direction, namely, a first end and a second end. A distance between the first end and a geometric center of the core back in the second direction is smaller than a distance between the second end and a geometric center of the core back in the second direction.

5. The magnetic core according to any one of claims 1 to 4, characterized in that: The tooth tip portion has two ends in the second direction, namely, a third end and a fourth end. A distance between the third end and a geometric center of the core back in the second direction is smaller than a distance between the fourth end and a geometric center of the core back in the second direction.

6. The magnetic core according to any one of claims 1 to 5, characterized in that: The orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as the third direction. A line connecting geometric centers of cross sections of the tooth body portion perpendicular to the third direction is defined as a first line, The first line is a straight line, The position of the first line at the terminal end of the tooth body portion and the position of the first line at the end portion of the tooth body portion on the opposite side to the terminal end are equal in the second direction.

7. The magnetic core according to any one of claims 1 to 5, characterized in that: The orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as the third direction. A line connecting geometric centers of cross sections of the tooth body portion perpendicular to the third direction is defined as a first line, The first line is a straight line, The position of the first line at the terminal end of the tooth body portion and the position of the first line at an end portion of the tooth body portion on the opposite side to the terminal end are offset in the second direction.

8. The magnetic core according to any one of claims 1 to 5, characterized in that: The orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as the third direction. A line connecting geometric centers of cross sections of the tooth body portion perpendicular to the third direction is defined as a first line, The first line is a broken line, The position of the first line at the terminal end of the tooth body portion and the position of the first line at an end portion of the tooth body portion on the opposite side to the terminal end are offset in the second direction.

9. The magnetic core according to any one of claims 1 to 6, characterized in that: The orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as the third direction. The core back has a shape that is symmetrical with respect to a plane perpendicular to the second direction. The tooth body has a shape that is symmetrical with respect to a plane perpendicular to the second direction. The tooth tip portion has a shape that is symmetrical with respect to a plane perpendicular to the second direction.

10. The magnetic core according to any one of claims 1 to 9, characterized in that: The orthographic projection of the first direction onto a plane orthogonal to the second direction is defined as the third direction. In the third direction, the length of the tooth body portion in the second direction is uniform.

11. The magnetic core according to any one of claims 1 to 10, characterized in that: The core back and the teeth are each a molded body formed of soft magnetic powder.

12. The magnetic core according to claim 11, characterized in that The material of the soft magnetic powder includes iron and resin.

13. A rotating electrical machine, characterized in that: A magnetic core according to any one of claims 1 to 12 is provided.

14. A brushless motor, characterized in that: A magnetic core according to any one of claims 1 to 12 is provided.

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