Stator for axial gap motor, and axial gap motor

Abstract

To improve deterioration of characteristics of an axial gap motor.SOLUTION: A stator for an axial gap motor has: a stator core having a back yoke and a plurality of teeth; and armature coils wound around respective ones of the plurality of teeth. The stator core has a plurality of divided cores divided in a circumferential direction. Each of the plurality of divided cores has an engaging portion used to position a circumferentially adjacent divided core. A radial position of the engaging portion does not coincide with radial positions of the plurality of teeth over the entire circumference in the circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stator for an axial gap motor and an axial gap motor. [Background technology]

[0002] Recently, axial gap motors have become known for use in EVs (electric vehicles), etc. Axial gap motors have a structure in which the surfaces of a disk-shaped rotor and a stator face each other in the axial direction, allowing for a small axial size and high torque.

[0003] A known structure for the stator of such an axial gap motor is to prepare multiple segments by dividing the stator core in the circumferential direction and then combine these segments to form the stator core. Patent Document 1 discloses a structure in which adjacent segments are provided with protrusions and recesses to position the multiple segments when they are combined. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-48751 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, magnetic flux passes through the positions of the convex and concave portions of adjacent segments in the stator core, which causes the magnetic flux to cross the gap between the segments, which has a complex shape due to the convex and concave portions, resulting in a problem of deterioration in motor performance.

[0006] An object of the present invention is to improve the characteristics of an axial gap motor against deterioration. [Means for solving the problem]

[0007] A stator according to one aspect of the present invention is a stator for an axial gap motor, comprising a stator core having a back yoke and a plurality of teeth, and an armature coil wound around each of the plurality of teeth, wherein the stator core has a plurality of split cores divided circumferentially, each of the plurality of split cores having a fitting portion that positions it with an adjacent split core in the circumferential direction, and the radial position of the fitting portion does not coincide with the radial position of the plurality of teeth over the entire circumferential direction.

[0008] In the stator according to the above aspect, the stator core is a powder magnetic core.

[0009] In the stator according to one aspect of the present invention, each of the plurality of split cores has the fitting portion on both the radially inner side and the radially outer side of the plurality of teeth.

[0010] In the stator according to one aspect of the present invention, each of the plurality of split cores has the fitting portion only on either the radially inner side or the radially outer side of the plurality of teeth.

[0011] In one aspect of the stator described above, each of the multiple split cores has the fitting portion only radially inward of the multiple teeth, each of the multiple split cores does not have the back yoke radially outward from the multiple teeth over the entire circumferential direction, and each of the multiple split cores does not have the back yoke radially inward from the multiple teeth only at the circumferential position of the multiple teeth.

[0012] An axial gap motor according to one aspect of the present invention is characterized by having a rotor and the stator according to the above aspect that faces the rotor across a gap. [Effects of the Invention]

[0013] According to one aspect of the present invention, it is possible to improve the deterioration of characteristics of an axial gap motor. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an exploded perspective view of a motor 100 according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a stator core 131 of FIG. [Figure 3] FIG. 3 is a diagram showing the vicinity of a split core 131a in FIG. 2. [Figure 4] FIG. 10 is a diagram showing a stator core 1131 according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing a stator core 2131 according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a motor according to an embodiment of the present invention will be described with reference to the drawings. Note that in the drawings, the scale and number of components may differ from the actual structure in order to make each component easier to understand.

[0016] The direction in which the central axis J shown in FIG. 1 extends is referred to as the axial direction. In the axial direction, the left side of FIG. 1 is referred to as the "one side," and the right side of FIG. 1 is referred to as the "other side." Note that the terms "one side" and "other side" are names used merely for the purpose of explanation and do not limit the actual positional relationship or direction. Furthermore, unless otherwise specified, the radial direction centered on the central axis J is simply referred to as the "radial direction," and the circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, is simply referred to as the "circumferential direction." In the radial direction, the side closer to the central axis J is referred to as the "radially inner side," and the side away from the central axis J is referred to as the "radially outer side." In the circumferential direction, the clockwise side when viewed from the left side of FIG. 1 is referred to as the "one circumferential side," and the counterclockwise side is referred to as the "other circumferential side."

[0017] In this specification, "extending in the axial direction" includes not only extending strictly in the axial direction but also extending in a direction tilted by less than 45° with respect to the axial direction. Furthermore, in this specification, "extending in the radial direction" includes not only extending strictly in the radial direction, i.e., in a direction perpendicular to the axial direction, but also extending in a direction tilted by less than 45° with respect to the radial direction. Furthermore, "parallel" includes not only being strictly parallel but also being tilted by an angle of less than 45° with respect to the direction perpendicular to the axial direction. Furthermore, "extending in a direction perpendicular to the axial direction" includes not only extending in a direction perpendicular to the axial direction but also extending in a direction tilted by less than 45° with respect to the direction perpendicular to the axial direction.

[0018] First Embodiment FIG. 1 is a perspective view of a motor 100 according to a first embodiment of the present invention. The motor 100 is an example of an axial gap motor. The motor 100 has a rotor 110, a shaft 113, a stator 120, and a stator 130. The shaft 113 is the rotation axis of the motor 100, extending axially along a central axis J. The shaft 113 is fixed to the rotor 110. The motor 100 according to this embodiment has the stator 120 and the stator 130 on both axial sides of the rotor 110, but the present invention is not limited to this and can also be applied to a motor having a stator on only one axial side of the rotor.

[0019] The rotor 110, the stator 120, and the stator 130 are each a substantially disk-shaped member. The stator 120 is disposed on one axial side of the rotor 110 with a gap therebetween. The stator 130 is disposed on the other axial side of the rotor 110 with a gap therebetween.

[0020] The stator 120 has a stator core 121 and an armature coil 124. The stator core 121 has a disk-shaped back yoke 122 and a plurality of teeth 123 arranged in the circumferential direction and extending from a surface on the other axial side of the back yoke 122 to the other axial side. The armature coil 124 is arranged by being wound around each of the plurality of teeth 123 of the stator core 121. The stator 130 has a stator core 131 and an armature coil 134. The stator core 131 has a disk-shaped back yoke 132 and a plurality of teeth 133 arranged in the circumferential direction and extending from a surface on one axial side of the back yoke 132 to one axial side. The armature coil 134 is arranged by being wound around each of the plurality of teeth 133 of the stator core 131.

[0021] The rotor 110 has a rotor frame 111 and magnets 112. The rotor frame 111 is a disk-shaped member. The magnets 112 are fitted into through holes that pass through the rotor frame 111 in the axial direction, and are fixed thereto by, for example, an adhesive.

[0022] Fig. 2 is a diagram showing stator core 131 in Fig. 1. Stator core 121 has the same configuration as stator core 131, so the following will describe stator core 131, and description of stator core 121 will be omitted.

[0023] In this embodiment, the stator core 131 is a powder magnetic core obtained by compacting and heat-treating soft magnetic iron powder covered with an insulating film. The present invention is not limited to this, and the stator core 131 may be a laminated steel plate obtained by stacking electromagnetic steel plates. The stator core 131 has a plurality of split cores 131a divided in the circumferential direction. Each of the plurality of split cores 131a has a back yoke 132 and teeth 133. In this embodiment, each split core 131a has one tooth 133. The present invention is not limited to this, and each split core 131a may have a plurality of teeth 133. The stator core 131 is formed by assembling a plurality of split cores 131a in the circumferential direction. Circumferentially adjacent split cores 131a are fixed to each other, for example, with an adhesive.

[0024] Each of the multiple split cores 131a has a side 132f on one circumferential side that faces the split core 131a adjacent to it on one circumferential side. Each of the multiple split cores 131a has a side 132e on the other circumferential side that faces the split core 131a adjacent to it on the other circumferential side. Each of the multiple split cores 131a has, on the side 132f, protrusions 132c and 132d that protrude from the side 132f toward one circumferential side. Furthermore, each of the multiple split cores 131a has, on the side 132e, recesses 132a and 132b that are recessed from the side 132e toward one circumferential side.

[0025] When assembling multiple split cores 131a to form the stator core 131, the protrusions 132c and 132d of one split core 131a are fitted into the recesses 132a and 132b of the adjacent split core 131a on one circumferential side. The protrusions 132c and 132d and the recesses 132a and 132b of the split core 131a are an example of a fitting portion that fits with the adjacent split core 131a. Note that in this embodiment, the fitting portion is semicircular, but the fitting portion may have any other shape, such as a polygonal shape. In addition, in this embodiment, the fitting portion has the same shape throughout the entire axial thickness of the stator core 131. However, it may have a different shape in the axial direction, for example, a recess or protrusion may be provided only halfway through the thickness, or it may have any known joint shape. Furthermore, the fitting portion may have a different shape on the radially inner side and the radially outer side of the tooth 133.

[0026] In this embodiment, the convex portions 132c and 132d and the concave portions 132a and 132b of the split core 131a serve as positioning elements when the split cores 131a are assembled together.

[0027] FIG. 3 is a diagram illustrating the vicinity of the split core 131a in FIG. 2. In this embodiment, the radial positions of the mating portions (the convex portions 132c and 132d and the concave portions 132a and 132b) of the split core 131a are offset from the radial positions of the teeth 133 over the entire circumferential direction. That is, the radial positions of the mating portions of the split core 131a do not coincide with the radial positions of the teeth 133 over the entire circumferential direction. Therefore, the magnetic flux passing through the teeth 133, as indicated by the arrows in FIG. 3, does not cross the complexly shaped gaps of the mating portions, thereby improving the performance degradation of the motor 100. That is, this embodiment facilitates the positioning and assembly of the split cores while minimizing the impact on the performance.

[0028] In this embodiment, fitting portions are provided on the radially inner and outer sides of the teeth 133, but the present invention is not limited to this, and fitting portions may be provided only on the radially inner sides of the teeth 133, or fitting portions may be provided only on the radially outer sides of the teeth 133.

[0029] Second Embodiment 4 is a diagram showing a stator core 1131 according to a second embodiment of the present invention. In the second embodiment, the motor 100 has a stator core 1131 instead of the stator core 131 of the first embodiment. The motor 100 according to the second embodiment is similar to the first embodiment except for having the stator core 1131. In the second embodiment, the stator core corresponding to the stator core 121 of the first embodiment also has the same configuration as the stator core 1131.

[0030] The stator core 1131 has a plurality of split cores 1131a separated in the circumferential direction. Each of the plurality of split cores 1131a has a back yoke 1132 and teeth 1133. The stator core 1131 is formed by assembling the plurality of split cores 1131a in the circumferential direction.

[0031] Each of the multiple split cores 1131a has a side 1132f on one circumferential side that faces the split core 1131a adjacent to it on one circumferential side. Each of the multiple split cores 1131a has a side 1132e on the other circumferential side that faces the split core 1131a adjacent to it on the other circumferential side. Each of the multiple split cores 1131a has a protrusion 1132d on the side 1132f that protrudes from the side 1132f toward one circumferential side. Furthermore, each of the multiple split cores 1131a has a recess 1132b on the side 1132e that recesses from the side 1132e toward one circumferential side.

[0032] Furthermore, the split core 1131a does not have a back yoke 1132 radially outward from the teeth 1133 along the entire circumferential direction. Furthermore, the split core 1131a does not have a back yoke 1132 radially inward from the teeth 1133, but only at the circumferential position of the teeth 1133. In this embodiment, the area of the back yoke 1132 can be reduced, thereby enabling a reduction in radial dimensions and weight. Furthermore, the radially protruding portion of the back yoke causes unnecessary iron loss because magnetic flux passes through it in the radial direction, so it is desirable to reduce the magnetic permeability of this portion. According to this embodiment, the magnetic flux flowing in the radial direction can be suppressed, thereby reducing iron loss.

[0033] When assembling multiple split cores 1131a to form the stator core 1131, the protrusion 1132d of one split core 1131a is fitted into the recess 1132b of the adjacent split core 1131a on one circumferential side. The protrusion 1132d and recess 1132b of the split core 1131a are an example of a fitting portion that fits with the adjacent split core 1131a.

[0034] In this embodiment, the convex portion 1132d and the concave portion 1132b of the split core 1131a serve as positioning elements when the split cores 1131a are assembled together.

[0035] In this embodiment, the radial positions of the mating portions (protrusions 1132d and recesses 1132b) of the split core 1131a are offset from the radial positions of the teeth 1133 over the entire circumferential direction. In other words, the radial positions of the mating portions of the split core 1131a do not coincide with the radial positions of the teeth 1133 over the entire circumferential direction. Therefore, the magnetic flux passing through the teeth 1133 does not need to cross the gaps of the complex shape of the mating portions, and deterioration of the characteristics of the motor 100 can be improved.

[0036] <Third embodiment> 5 is a diagram showing a stator core 2131 according to a third embodiment of the present invention. In the third embodiment, the motor 100 has a stator core 2131 instead of the stator core 131 of the first embodiment. The motor 100 according to the third embodiment is similar to the first embodiment except for having the stator core 2131. In the third embodiment, the stator core corresponding to the stator core 121 of the first embodiment also has the same configuration as the stator core 2131.

[0037] The stator core 2131 has a plurality of split cores 2131a that are split in the circumferential direction. Each of the plurality of split cores 2131a has a back yoke 2132 and teeth 2133. The stator core 2131 is formed by assembling the plurality of split cores 2131a in the circumferential direction.

[0038] Each of the multiple split cores 2131a has a side 2132f, which is a side on one circumferential side that faces the split core 2131a adjacent to it on one circumferential side. Each of the multiple split cores 2131a has a side 2132e, which is a side on the other circumferential side that faces the split core 2131a adjacent to it on the other circumferential side. Each of the multiple split cores 2131a has a recess 2132a, which is recessed from the side 2132f toward the other circumferential side, on the side 2132f. Each of the multiple split cores 2131a has a protrusion 2132d, which protrudes from the side 2132f toward one circumferential side, on the side 2132f. Furthermore, each of the multiple split cores 2131a has a protrusion 2132c, which protrudes from the side 2132e toward the other circumferential side. Each of the plurality of split cores 2131a has a side 2132e formed with a recess 2132b recessed from the side 2132e toward one side in the circumferential direction.

[0039] When assembling multiple split cores 2131a to form the stator core 2131, the convex portion 2132d of one split core 2131a is fitted into the concave portion 2132b of the split core 2131a adjacent on one circumferential side. Similarly, the convex portion 2132c of one split core 2131a is fitted into the concave portion 1132a of the split core 2131a adjacent on the other circumferential side. The convex portions 2132c and 2132d and the concave portions 2132a and 2132b of the split core 2131a are examples of fitting portions that fit with adjacent split cores 2131a.

[0040] In this embodiment, the convex portions 2132c and 2132d and the concave portions 2132a and 2132b of the split core 2131a serve as positioning elements when the split cores 2131a are assembled together.

[0041] In this embodiment, the radial positions of the fitting portions (protrusions 2132c and 2132d, and recesses 2132a and 2132b) of the split core 2131a are offset from the radial positions of the teeth 2133 over the entire circumferential direction. In other words, the radial positions of the fitting portions of the split core 2131a do not coincide with the radial positions of the teeth 2133 over the entire circumferential direction. Therefore, the magnetic flux passing through the teeth 2133 does not need to cross the gaps of the complex shape of the fitting portions, and deterioration of the characteristics of the motor 100 can be improved.

[0042] The present invention is not limited to the above-described embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention. In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0043] 100...motor, 113...shaft, 110...rotor, 111...rotor frame, 112...magnet, 120, 130...stator, 131a...segment core

Claims

1. A stator for an axial gap motor, a stator core having a back yoke and a plurality of teeth; an armature coil wound around each of the plurality of teeth; and the stator core has a plurality of divided cores divided in the circumferential direction, Each of the plurality of split cores has a fitting portion that determines the position of the split core with an adjacent split core in the circumferential direction, The radial position of the fitting portion does not coincide with the radial position of the plurality of teeth over the entire circumferential direction. A stator characterized by:

2. The stator core is a powder magnetic core.

2. The stator according to claim 1.

3. Each of the plurality of split cores has the fitting portion on both a radially inner side and a radially outer side of the plurality of teeth.

2. The stator according to claim 1.

4. Each of the plurality of split cores has the fitting portion only on either a radially inner side or a radially outer side of the plurality of teeth.

2. The stator according to claim 1.

5. each of the plurality of split cores has the fitting portion only on a radially inner side of the plurality of teeth, Each of the plurality of split cores does not have the back yoke radially outward from the plurality of teeth over the entire circumferential direction, Each of the plurality of split cores does not have the back yoke radially inward from the plurality of teeth only at a circumferential position of the plurality of teeth.

2. The stator according to claim 1.

6. A rotor, the stator according to claim 1 , which faces the rotor across a gap; having An axial gap motor characterized by:

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