Axial gap motor

Abstract

To achieve both ensuring mechanical strength of a stator and reducing heat generation.SOLUTION: There is provided an axial gap motor having a stator and a rotor axially opposed to the stator. The stator has a plurality of stator cores arranged in a circumferential direction, and a stator case for accommodating the stator cores. The stator core has a facing part facing the rotor at an axial end. The stator case is made of a metal material. The stator case has an opening for exposing the facing part toward the rotor. The stator case has a cut part where at least a part of an area surrounding the opening is cut. The cut part is located on a radially outer side or a radially inner side of the opening.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to an axial gap motor.

Background Art

[0002] In an axial gap motor, a stator and a rotor are arranged such that they face each other through a gap in the axial direction. The stator of this axial gap motor is configured by housing a plurality of starter cores arranged in the circumferential direction in a case.

[0003] By the way, when the case is made of a metal material, there is a problem that eddy currents are generated in the case and heat is generated by these eddy currents. Therefore, in Patent Document 1, by making the case of a resin material, generation of eddy currents can be prevented and heat generation of the case can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the case is made of a resin material as in Patent Document 1, there is a problem that since the mechanical strength of the case is weaker than that of the case made of a metal material, it may be disadvantageous in miniaturization and high density.

[0006] For this reason, conventionally, there has been room for improvement in achieving both ensuring the mechanical strength of the stator of the axial gap motor and reducing heat generation.

[0007] An object of the present invention is to improve in achieving both ensuring the mechanical strength of the stator and reducing heat generation.

Means for Solving the Problems

[0008] An axial gap motor according to one aspect of the present invention is an axial gap motor having a stator and a rotor facing the stator in the axial direction, wherein the stator has a plurality of stator cores arranged in the circumferential direction and a stator case housing the stator cores, the stator cores have facing portions at their axial ends that face the rotor, the stator case is made of a metal material, the stator case has an opening that exposes the facing portions toward the rotor, the stator case has a cut portion in which at least a part of the portion surrounding the opening is cut off, and the cut portion is of the opening Radial outer It is located in [location].

[0009] In the axial gap motor according to one embodiment described above, the stator case is Arranged on both sides in the circumferential direction of the opening, It has a plurality of frame parts arranged at equal intervals in the circumferential direction, and each of the plurality of frame parts is on the radially outer side of the opening Having an outer diameter portion, The aforementioned cut portion is It is located between adjacent outer diameter portions in the circumferential direction of each of the multiple frame portions.

[0010] In the axial gap motor according to one embodiment described above, the stator case is Arranged on both sides in the circumferential direction of the opening, It has a plurality of frame parts arranged at equal intervals in the circumferential direction, each of the plurality of frame parts has an outer diameter part at its radially outer end, each of the plurality of frame parts has an inner diameter part at its radially inner end, each of the plurality of frame parts is connected to an adjacent frame part only by either the outer diameter part or the inner diameter part, and the frame part of the plurality of frame parts that is connected to an adjacent frame part on the other side in the circumferential direction by the outer diameter part is connected to an adjacent frame part on one side in the circumferential direction by the inner diameter part, and the outer diameter part of each of the plurality of frame parts that is connected to the outer diameter part of the frame part adjacent to the other side in the circumferential direction and, The cutting portion is located between the outer diameter portion of an adjacent frame portion on one side in the circumferential direction. It is located, Outer diameter portion of each of the plurality of frame portions that is connected to the outer diameter portion of an adjacent frame portion on one side in the circumferential direction and,The cutting portion is located between the outer diameter portion of the frame portion adjacent to the other side in the circumferential direction. It is located, The inner diameter portion of each of the plurality of frame portions that is connected to the inner diameter portion of the frame portion adjacent to the other frame portion in the circumferential direction. and, The cutting portion is located between the inner diameter portion of the adjacent frame portion on one side in the circumferential direction. It is located, The inner diameter portion of each of the plurality of frame portions that is connected to the inner diameter portion of the frame portion adjacent to it in the circumferential direction on one side of the inner diameter portion of the frame portion. and, The cutting portion is located between the inner diameter portion of the adjacent frame portion on the other side in the circumferential direction. It is located there. [Effects of the Invention]

[0011] According to one aspect of the present invention, it is possible to improve the ability to achieve both the securing of the mechanical strength of the stator and the reduction of heat generation. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of a motor according to the first embodiment of the present invention. [Figure 2] This is a side cross-section of the motor 10 in Figure 1, taken by cutting it through a plane passing through the central axis J and perpendicular to the X-axis. [Figure 3] Figure 1 is an exploded perspective view of motor 10 as seen from the -Z side. [Figure 4] This is a perspective view showing the stator 11 of the motor 10 in Figure 1. [Figure 5] Figure 4 is a perspective view showing the stator 11 with the stator case 112 removed. [Figure 6] This is a perspective view showing the state after removing the stator core unit 120 from the state shown in Figure 5. [Figure 7] This figure shows modified examples of the stator case and inner diameter member that can be used in place of the stator case 112 and inner diameter member 114 shown in Figure 4. [Figure 8] This figure shows the eddy current loss density calculated by electromagnetic field analysis. [Figure 9] This figure shows a stator case according to a second embodiment of the present invention. [Figure 10]It is a diagram showing a stator case according to a third embodiment of the present invention.

Embodiments for Carrying out the Invention

[0013] Hereinafter, an axial gap motor according to an embodiment of the present invention will be described with reference to the drawings. In the following drawings, in order to make each configuration easier to understand, the actual structure, the scale and the number in each structure may be made different.

[0014] Also, in the drawings, the XYZ coordinate system is shown as a three-dimensional orthogonal coordinate system as appropriate. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the central axis J shown in FIG. 1. The Y-axis direction is the vertical direction in FIG. 2 among the radial directions with respect to the central axis J. The X-axis direction is a direction orthogonal to both the Z-axis direction and the Y-axis direction. In any of the X-axis direction, the Y-axis direction, and the Z-axis direction, the side pointed by the arrow shown in the figure is the + side, and the opposite side is the - side.

[0015] Also, in the following description, the positive side (+Z side) in the Z-axis direction is called "one side", and the negative side (-Z side) in the Z-axis direction is called "the other side". Note that the one side and the other side are names used merely for explanation and do not limit the actual positional relationship and direction. Also, unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) is simply called the "axial direction", the radial direction centered on the central axis J is simply called the "radial direction", and the circumferential direction centered on the central axis J, that is, the circumference around the central axis J is simply called the "circumferential direction". The side approaching the central axis J in the radial direction is called the "radial inner side", and the side moving away from the central axis J is called the "radial outer side". In the circumferential direction, the clockwise side when looking from the +Z side to the -Z side is called the "circumferential one side", and the counterclockwise side is called the "circumferential other side".

[0016] In this specification, "extending in the axial direction" includes not only cases where the extension is strictly in the axial direction (Z-axis direction), but also cases where the extension is inclined in a direction with an angle of less than 45° relative to the axial direction. Furthermore, in this specification, "extending in the radial direction" includes not only cases where the extension is strictly in the radial direction, i.e., perpendicular to the axial direction (Z-axis direction), but also cases where the extension is inclined in a direction with an angle of less than 45° relative to the radial direction. Furthermore, "parallel" includes not only cases where the extension is strictly parallel, but also cases where the angle between them is inclined in a range of less than 45°. Furthermore, "spreading in a direction perpendicular to the axial direction" includes not only cases where the extension spreads in a direction perpendicular to the axial direction (Z-axis direction), but also cases where the extension spreads in a direction with an angle of less than 45° relative to the direction perpendicular to the axial direction (Z-axis direction).

[0017] <First Embodiment> Figure 1 is a perspective view of a motor according to a first embodiment of the present invention. The motor 10 in Figure 1 is an example of an axial gap motor. Figure 2 is a side cross-sectional view of the motor 10 in Figure 1, taken by cutting it through a plane passing through the central axis J and perpendicular to the X axis.

[0018] The motor 10 includes a shaft 14 extending along a central axis J, a stator 11, a frame 12 positioned on one axial side of the stator 11, and a frame 13 positioned on the other axial side of the stator 11. The stator 11 has a stator case 111 and a stator case 112. The stator case 111 is a bottomed cylindrical shape with a bottom on the other axial side. The stator case 112 is a disc shape. The stator 11 is constructed by housing a stator core 121 (see Figure 5) in the space formed within the stator cases 111 and 112 when the stator cases 111 and 112 are combined.

[0019] The motor 10 has an inlet 16 for introducing coolant into the stator 11 and an outlet 15 for releasing the coolant from the stator 11. The inlet 16 is located on the -Y side of the stator 11, and the outlet 15 is located on the +Y side of the stator 11. The inlet 16 is fitted into a through hole 111b of the stator case 111, and the outlet 15 is fitted into a through hole 111a of the stator case 111.

[0020] The motor 10 has a rotor 20 and a rotor 21. The rotor 20 is axially opposed to the stator 11 and is positioned axially to one side of the stator 11. The frame 12 covers the rotor 20 from one side in the axial direction. The frame 12 is fixed to the stator case 111. The rotor 21 is axially opposed to the stator 11 and is positioned axially to the other side of the stator 11. The frame 13 covers the rotor 21 from the other side in the axial direction. The frame 13 is fixed to the stator case 112.

[0021] Frame 12 has a through hole 12a that penetrates in the axial direction. The inner diameter member 113, which will be described in detail later, has a through hole 113c that penetrates in the axial direction. The inner diameter member 114, which will be described in detail later, has a through hole 114a that penetrates in the axial direction. Frame 13 has a through hole 13a that penetrates in the axial direction. The shaft 14 penetrates through holes 12a, 113c, 114a, and 13a.

[0022] The motor 10 has bearings 22a and 22b. Bearing 22a is located radially inward of the through hole 12a. Bearing 22b is located radially inward of the through hole 13a. Bearings 22a and 22b support the shaft 14 so that it can rotate along the central axis J.

[0023] The rotor 20 has a rotor core 20a and magnets 20b. The rotor core 20a is disc-shaped. The magnets 20b are fixed to the surface of the rotor core 20a that faces the stator 11 (the surface on the other axial side). The magnets 20b face the stator 11 through a gap. In this embodiment, the rotor 20 has eight magnets 20b arranged in the circumferential direction. The number of magnets 20b is not limited to this.

[0024] The rotor 21 has a rotor core 21a and magnets 21b. The rotor core 21a is disc-shaped. The magnets 21b are fixed to the surface of the rotor core 21a that faces the stator 11 (the surface on one axial side). The magnets 21b face the stator 11 through a gap. In this embodiment, the rotor 21 has eight magnets 21b arranged in the circumferential direction. The number of magnets 21b is not limited to this. The rotor core 20a and rotor core 21a are fixed to the shaft 14.

[0025] Figure 3 is an exploded perspective view of the motor 10 of Figure 1, viewed from the -Z side. The motor 10 has bolts 17a and 17b. The frame 12 is fixed to one axial side of the stator 11 by bolt 17a. The frame 13 is fixed to the other axial side of the stator 11 by bolt 17b.

[0026] Figure 4 is a perspective view showing the stator 11 of the motor 10 in Figure 1. Figure 5 is a perspective view showing the stator 11 of Figure 4 with the stator case 112 removed. The stator case 112 has a bolt hole 112a into which a bolt 17a fits. The stator 11 has a bolt 115. The stator case 112 has a bolt hole 112b into which a bolt 115 fits. The stator case 112 is fixed to the stator case 111 by the bolt 115. The stator case 111 has a bolt hole (not shown) on the other axial side into which a bolt 17b fits. The stator case 111 has a bolt hole 111f into which a bolt 115 fits.

[0027] The stator 11 has a stator core 121. One axial end of the stator core 121 is an example of a facing portion that faces the rotor 20. The other axial end of the stator core 121 is an example of a facing portion that faces the rotor 21. A configuration in which the stator core 121 is covered with a bobbin (not shown) and a coil (not shown) is wound around it is called a stator core unit 120. In this embodiment, the stator 11 has 12 stator cores 121 arranged in the circumferential direction. The number of stator cores 121 is not limited to this.

[0028] The stator case 112 is made of a metal material. The stator case 112 has an opening 112c through which one axial end of the stator core 121 is exposed. There are the same number of openings 112c as there are stator cores 121.

[0029] The stator case 112 has a frame portion 112d. The frame portion 112d extends radially from the outer edge to the inner edge of the surface facing the rotor 20 in the axial direction. Multiple frame portions 112d are arranged in the circumferential direction. The opening 112c is enclosed by the outer edge of the surface facing the rotor 20 in the axial direction, one of the multiple frame portions 112d, a frame portion 112d adjacent to this one frame portion 112d, and the inner edge of the surface facing the rotor 20 in the axial direction. The frame portion 112d has an end portion 112e at its radially inner end. The end portion 112e is an example of a cut portion in which at least a part of the portion surrounding the opening 112c is cut off. That is, in this case the cut portion is formed by cutting between the radially inner end of one of the multiple frame portions 112d and the radially inner end of a frame portion 112d adjacent to this one frame portion 112d.

[0030] The stator 11 has an inner diameter member 114. The inner diameter member 114 is an annular plate member. The inner diameter member 114 is made of a resin material. The outer circumference of the inner diameter member 114 is connected to the end portion 112e. The stator case 112 and the inner diameter member 114 are integrally molded, for example, by insert molding. The inner diameter member 114 is an example of a replacement portion that connects to a cut portion.

[0031] Figure 6 is a perspective view showing the state in which the stator core unit 120 has been removed from the state shown in Figure 5. The stator case 111 is made of a metal material. The stator case 111 has openings 111c through which the other axial end of the stator core 121 is exposed. There are the same number of openings 111c as there are stator cores 121.

[0032] The stator case 111 has a frame portion 111d. The frame portion 111d extends radially from the outer edge portion 111a, which is the outer edge of the surface facing the rotor 21 in the axial direction, toward the inner edge. Multiple frame portions 111d are arranged in the circumferential direction. The opening 111c is enclosed by the outer edge portion 111a, one of the multiple frame portions 111d, a frame portion 111d adjacent to this one frame portion 111d, and the inner edge of the surface facing the rotor 21 in the axial direction. The frame portion 111d has an end portion 111e at its radially inner end. The end portion 111e is an example of a cut portion in which at least a part of the portion surrounding the opening 111c is cut off. That is, in this case the cut portion is formed by cutting between the radially inner end of one of the multiple frame portions 111d and the radially inner end of a frame portion 112d adjacent to this one frame portion 111d.

[0033] The stator 11 has an inner diameter member 113. The inner diameter member 113 has an annular plate member, which is an annular portion 113a, and a cylindrical portion 113b, which is a cylindrical member extending axially from the inner circumference of the annular portion 113a. The annular portion 113a and the cylindrical portion 113b are a single integrated member. The inner diameter member 113 is made of a resin material. The outer circumference of the annular portion 113a is connected to the end portion 111e. The stator case 111 and the inner diameter member 113 are integrally molded, for example, by insert molding. The inner diameter member 113 is an example of a replacement portion connected to a cut portion.

[0034] Figure 7 shows modified examples of the stator case and inner diameter member that can be used in place of the stator case 112 and inner diameter member 114 shown in Figure 4. Figure 7 is a plan view of the modified stator case 1112 and inner diameter member 1114 as seen from one side in the axial direction.

[0035] The stator case 1112 is made of a metal material. The stator case 1112 has a frame portion 1112d. The frame portion 1112d has an end portion 1112e at its radially inner end. The inner diameter member 1114 is an annular plate member. The inner diameter member 1114 is made of a resin material. The outer circumference of the inner diameter member 114 is connected to the end portion 1112e. The end portion 1112e has a recess 1112f that is recessed radially outward. The outer circumference of the inner diameter member 114 has a convex portion 1114b that protrudes radially outward. The recess 1112f and the convex portion 1114b fit together. The recess 1112f and the convex portion 1114b are examples of fitting portions that fit the radially inner ends of a plurality of frame portions 1112d with the inner diameter member 1114 as a filling portion. This prevents the frame portion 1112d and the inner diameter member 1114 from coming apart more effectively than in the example of the stator case 112 and inner diameter member 114. The stator case 111 can also be constructed in a similar manner.

[0036] Figure 8 shows the eddy current loss density calculated by electromagnetic field analysis. Figure 8(A) shows the eddy current loss density for an example where the frame parts are connected by metal on the inner diameter side without using the inner diameter member 114. Figure 8(B) shows the eddy current loss density for an example where the inner diameter member 114 is used, as shown in Figure 4.

[0037] In the example shown in Figure 8(A), the stator case 2112 is made of metal. Multiple frame sections 2112d are connected by radially inner sections 2113, all of which are metal, creating eddy current paths that surround the ends of the stator coils. As a result, the eddy current loss density is high in the example shown in Figure 8(A).

[0038] In the example shown in Figure 8(B), the stator case 112 is made of a metal material, while the inner diameter member 114 is made of a resin material. As a result, there is no path for eddy currents surrounding the end of the stator coil. Consequently, the eddy current loss density in the example shown in Figure 8(B) is lower than in the example shown in Figure 8(A). Therefore, it can be seen that the loss is significantly reduced by the structure of this embodiment.

[0039] <Second Embodiment> Figure 9 shows a stator case according to a second embodiment of the present invention. The stator case 3112 of this embodiment can be used in place of the stator case 112 and inner diameter member 114 shown in Figure 4. Figure 9 is a plan view of the stator case 3112 as seen from one side in the axial direction. The stator case 3112 is disc-shaped, similar to the stator case 112. Below, the differences from the first embodiment will be described, and a detailed explanation of the similarities to the first embodiment will be omitted.

[0040] As shown in Figure 4, the stator 11 of the first embodiment is constructed by housing the stator core 121 in the space formed within the stator cases 111 and 112 when the stator cases 111 and 112 are combined. The stator case 112 of the first embodiment is a stator case corresponding to a configuration having 12 stator cores 121 arranged at equal intervals in the circumferential direction. In contrast, the stator case 3112 of the second embodiment is a stator case corresponding to a configuration having 36 stator cores arranged at equal intervals in the circumferential direction.

[0041] In this embodiment, a stator case 3112 made of metal material is used, which extends radially inward to the location where the inner diameter member 114 was used in the first embodiment. The position of the radially inward end of the stator case 3112 is located further radially outward than the position of the radially inward end of the stator case 112. The inner diameter member in the second embodiment, which corresponds to the inner diameter member 113 that is axially opposed to the inner diameter member 114 of the first embodiment, is axially opposed to the inner diameter portion 3114 of the stator case 3112.

[0042] The stator case 3112 has a frame portion 3115 surrounding an opening 3116 through which one axial end of the stator core is exposed. The stator case 3112 has a plurality of frame portions 3115 arranged at equal intervals in the circumferential direction. The stator case 3112 has an inner diameter portion 3114 at its radially inner end. The inner diameter portion 3114 connects the plurality of frame portions 3115 to each other on the inner diameter side. The inner diameter portion 3114 has bolt holes 3119. The stator case 3112 is fixed to the inner diameter member in the second embodiment, which corresponds to the inner diameter member 113 in the first embodiment, by bolts passing through the bolt holes 3119.

[0043] Each frame portion 3115 has an outer diameter portion 3113 at its radially outer end. Each of the multiple frame portions 3115 is separated from an adjacent frame portion 3115 by having a slit 3117 between its own outer diameter portion 3113 and the outer diameter portion 3113 of the adjacent frame portion 3115. Each of the multiple frame portions 3115 has a bolt hole 3118 in its outer diameter portion 3113. The stator case 3112 is fixed to the cylindrical portion in the second embodiment, which corresponds to the radially outer cylindrical portion of the stator case 111 in the first embodiment, by bolts passing through the bolt holes 3118. The slit 3117 penetrates the stator case 3112 axially. The slit 3117 is an example of a cut portion in which at least a part of the portion surrounding the opening 3116 is cut off. That is, in this case, the cut portion is formed by each of the multiple frame portions 3115 being cut off from an adjacent frame portion 3115 on its radially outer side. Each of the multiple frame sections 3115 is separated from the adjacent frame section 3115 on the radially outer side, on one side in the circumferential direction and on the other side in the circumferential direction.

[0044] In this embodiment, the slit 3117 is provided only on the outer diameter side of the opening 3116, but in the present invention, the slit may be provided only on the inner diameter side of the opening 3116.

[0045] As described above, according to this embodiment, by providing the slit 3117, the path of eddy currents generated around the opening 3116 can be interrupted. The stator case 111 can also be constructed in a similar manner.

[0046] As shown in Figure 2, the axial gap motor has a structure in which the stator is sandwiched between rotors to which magnets are attached. Therefore, the magnets on the rotor exert an attractive force that pulls the stator core in the axial direction. The slit 3117 is located radially outside the opening 3116 and is a slit that cuts the stator case 3112 in two directions, one side and the other side. In this embodiment, since the frame portion 3115 does not have slits that cut radially inward and radially outward, the strength against the axial attractive force can be increased.

[0047] <Third Embodiment> Figure 10 shows a stator case according to a third embodiment of the present invention. The stator case 4112 of this embodiment can be used in place of the stator case 3112 shown in Figure 9. Figure 10 is a plan view of the stator case 4112 as seen from one side in the axial direction. The stator case 4112 is disc-shaped, similar to the stator case 3112. Below, the differences from the second embodiment will be described, and a detailed explanation of the similarities with the second embodiment will be omitted.

[0048] The stator case 4112 has a frame portion 4115 surrounding an opening 4116 through which one axial end of the stator core is exposed. The stator case 4112 has a plurality of frame portions 4115 arranged at equal intervals in the circumferential direction. Each of the plurality of frame portions 4115 has an outer diameter portion 4113 at its radially outer end. The outer diameter portion 4113 connects two adjacent frame portions 4115. Each of the plurality of frame portions 4115 has an inner diameter portion 4114 at its radially inner end. The inner diameter portion 4114 connects two adjacent frame portions 4115.

[0049] Each of the multiple frame sections 4115 is connected to an adjacent frame section 4115 only by either its outer diameter section 4113 or its inner diameter section 4114. Of the multiple frame sections 4115, the frame section 4115 connected to an adjacent frame section 4115 on the other side in the circumferential direction by its outer diameter section 4113 is connected to an adjacent frame section 4115 on one side in the circumferential direction by its inner diameter section 4114. Furthermore, of the multiple frame sections 4115, the frame section 4115 connected to an adjacent frame section 4115 on the other side in the circumferential direction by its inner diameter section 4114 is connected to an adjacent frame section 4115 on one side in the circumferential direction by its outer diameter section 4113.

[0050] Of the outer diameter portions 4113 of each of the multiple frame portions 4115, the outer diameter portion 4113 connected to the outer diameter portion 4113 of the frame portion 4115 adjacent to it on the other side in the circumferential direction has a slit 4117 between it and the outer diameter portion 4113 of the frame portion 4115 adjacent to it on one side in the circumferential direction. Of the outer diameter portions 4113 of each of the multiple frame portions 4115, the outer diameter portion 4113 connected to the outer diameter portion 4113 of the frame portion 4115 adjacent to it on one side in the circumferential direction has a slit 4117 between it and the outer diameter portion 4113 of the frame portion 4115 adjacent to it on the other side in the circumferential direction.

[0051] Of the inner diameter portions 4114 of each of the multiple frame portions 4115, the inner diameter portion 4114 connected to the inner diameter portion 4114 of the frame portion 4115 adjacent to it on the other side in the circumferential direction has a slit 4120 between it and the inner diameter portion 4114 of the frame portion 4115 adjacent to it on one side in the circumferential direction. Of the inner diameter portions 4114 of each of the multiple frame portions 4115, the inner diameter portion 4114 connected to the inner diameter portion 4114 of the frame portion 4115 adjacent to it on one side in the circumferential direction has a slit between it and the inner diameter portion 4114 of the frame portion 4115 adjacent to it on the other side in the circumferential direction.

[0052] The outer diameter portion 4113 has bolt holes 4118. The stator case 4112 is fixed by bolts passing through the bolt holes 4118 to the cylindrical portion in the third embodiment, which corresponds to the radially outer cylindrical portion of the stator case 111 in the first embodiment.

[0053] The inner diameter portion 4114 has bolt holes 4119. The stator case 4112 is fixed to the inner diameter member in the third embodiment, which corresponds to the inner diameter member 113 in the first embodiment, by bolts passing through the bolt holes 4119.

[0054] Slits 4117 and 4120 penetrate the stator case 4112 axially. Slits 4117 and 4120 are examples of cut portions in which at least a part of the area surrounding the opening 4116 is cut off. In the cut portion by slit 4117, each of the multiple frame portions 4115 is cut from an adjacent frame portion 4115 radially outward. Each of the multiple frame portions 4115 is separated from an adjacent frame portion 4115 radially outward, on one side in the circumferential direction and the other side in the circumferential direction. In the cut portion by slit 4120, each of the multiple frame portions 4115 is cut from an adjacent frame portion 4115 radially inward. Each of the multiple frame portions 4115 is separated from an adjacent frame portion 4115 radially inward, on one side in the circumferential direction and the other side in the circumferential direction.

[0055] As described above, according to this embodiment, by providing slits 3117 and 4120, the path of eddy currents generated around the opening 4116 can be interrupted. The stator case 111 can also be constructed in a similar manner.

[0056] As shown in Figure 2, the axial gap motor has a structure in which the stator is sandwiched between rotors to which magnets are attached. Therefore, the magnets on the rotor exert an attractive force that pulls the stator core in the axial direction. Slits 4117 and 4120 are located radially outside or radially inside the opening 4116 and are slits that cut the stator case 4112 in one circumferential direction and the other circumferential direction. In this embodiment, since the frame portion 4115 does not have slits that cut radially inside and radially outside, the strength against axial attractive force can be increased.

[0057] In the second embodiment, the outer diameter portion 3113 is separated for each frame portion 3115, requiring the same number of bolt holes 3118 and bolts as the frame portion 3115. In contrast, in the third embodiment, adjacent outer diameter portions 4113 are connected to each other, so the number of bolt holes 4118 and bolts is only half the number of frame portions 4115, thus reducing costs.

[0058] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. In addition, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0059] 10...Motor, 11...Stator, 12...Frame, 13...Frame, 14...Shaft, 111...Stator case, 111c...Opening, 112...Stator case, 112c...Opening, 121...Stator core

Claims

1. An axial gap motor having a stator and a rotor facing the stator in the axial direction, The stator comprises a plurality of stator cores arranged in the circumferential direction and a stator case that houses the stator cores. The stator core has a portion at its axial end that faces the rotor, The stator case is made of a metal material. The stator case has an opening that exposes the opposing portion toward the rotor, The stator case has a cut portion in which at least a part of the portion surrounding the opening is cut off. The cut portion is located radially outward of the opening, Axial gap motor.

2. The stator case has a plurality of frame portions arranged on both sides of the opening in the circumferential direction and spaced equally apart in the circumferential direction, Each of the aforementioned plurality of frame portions has an outer diameter portion that is radially outside the opening, The cut portion is located between adjacent outer diameter portions in the circumferential direction among the outer diameter portions of each of the multiple frame portions. The axial gap motor according to claim 1.

3. The stator case has a plurality of frame portions arranged on both sides of the opening in the circumferential direction and spaced equally apart in the circumferential direction, Each of the aforementioned plurality of frame portions has an outer diameter portion at its radially outer end, Each of the aforementioned multiple frame portions has an inner diameter portion at its radially inner end, Each of the aforementioned plurality of frame portions is connected to an adjacent frame portion only by either the outer diameter portion or the inner diameter portion. Of the plurality of frame portions, the frame portion connected to the adjacent frame portion on the other side in the circumferential direction by the outer diameter portion is connected to the adjacent frame portion on one side in the circumferential direction by the inner diameter portion, Of the plurality of frame portions, the frame portion connected to the frame portion adjacent to the other side in the circumferential direction by the inner diameter portion is connected to the frame portion adjacent to the frame portion on one side in the circumferential direction by the outer diameter portion, The cutting portion is located between the outer diameter portion of each of the plurality of frame portions that is connected to the outer diameter portion of the frame portion adjacent to the other side in the circumferential direction, and the outer diameter portion of the frame portion adjacent to the one side in the circumferential direction. The cutting portion is located between the outer diameter portion of each of the plurality of frame portions that is connected to the outer diameter portion of an adjacent frame portion on one side in the circumferential direction, and the outer diameter portion of an adjacent frame portion on the other side in the circumferential direction. The cutting portion is located between the inner diameter portion of each of the plurality of frame portions that is connected to the inner diameter portion of the frame portion adjacent to the other side in the circumferential direction, and the inner diameter portion of the frame portion adjacent to the one side in the circumferential direction. The cutting portion is located between the inner diameter portion of each of the plurality of frame portions that is connected to the inner diameter portion of the frame portion adjacent to it on one side in the circumferential direction, and the inner diameter portion of the frame portion adjacent to it on the other side in the circumferential direction. The axial gap motor according to claim 1.

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