JP2023048672A - axial gap motor - Google Patents

Abstract

To provide a stator improved about compatibly satisfying acquisition of mechanical strength and reduction of heat generation.SOLUTION: An axial gap motor comprises a stator 11, and a rotor opposed to the stator in an axial direction. The stator comprises a plurality of stator cores 121 arranged in a circumferential direction, and a stator case 111 for storing the stator cores. The stator cores comprise a facing part opposed to the rotor at an axial direction end. The stator case is made of a metallic material. The stator case comprises an opening 112c exposed by directing the facing part toward the rotor. The stator case comprises a cutting part where at least part of a region surrounding the opening is cut.SELECTED DRAWING: Figure 4

Description

The present invention relates to axial gap motors.

An axial gap motor is arranged such that a stator and a rotor face each other across 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.

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 the eddy currents. Therefore, in Patent Document 1, the case is made of a resin material to prevent the occurrence of eddy currents and to suppress the heat generation of the case.

JP 2017-99191 A

However, when the case is made of a resin material as in Patent Document 1, the mechanical strength is weaker than when the case is made of a metal material. .

Therefore, conventionally, there has been room for improvement in both securing the mechanical strength of the stator of the axial gap motor and reducing heat generation.

An object of the present invention is to improve both securing of the mechanical strength of the stator and reduction of heat generation.

An axial gap motor according to an aspect of the present invention is an axial gap motor including a stator and a rotor axially facing the stator, wherein the stator includes a plurality of stator cores arranged in the circumferential direction; a stator case that houses the stator core, the stator core having a facing portion facing the rotor at an axial end thereof; the stator case being made of a metal material; toward the rotor, and the stator case has a cut portion in which at least a portion of a portion surrounding the opening is cut.

In one aspect of the axial gap motor described above, the stator case has a plurality of circumferentially arranged frame portions extending radially from an outer edge toward an inner edge of a surface axially facing the rotor, The opening includes an outer edge of a surface axially facing the rotor, one of the plurality of frame portions, a frame portion adjacent to the one frame portion, and a surface axially facing the rotor. surrounded by the inner edge of the

The axial gap motor of one aspect described above further includes a filling section connected to the cutting section, and the filling section is made of a resin material.

In one aspect of the axial gap motor described above, the cutting portion has a gap between a radially inner end of one of the plurality of frame portions and a radially inner end of a frame portion adjacent to the one frame portion. It consists of being cut.

The axial gap motor of one aspect described above has a fitting portion for fitting the radially inner ends of the plurality of frame portions and the filling portion.

In one aspect of the axial gap motor described above, the cut portion is formed by cutting the frame portion radially inwardly and radially outwardly.

In one aspect of the axial gap motor described above, the stator case has a lid portion including a surface facing the rotor in the axial direction, and the lid portion includes a plurality of plate members extending in a direction orthogonal to the axial direction. Each of the plurality of plate members has the plurality of frame portions, and each of the plurality of plate members has the cut portion in at least one of the plurality of frame portions. The cut portion of one of the plurality of plate members axially overlaps a frame portion that does not have the cut portion among the plurality of frame portions of another plate member different from the one plate member.

According to one aspect of the present invention, it is possible to improve both securing of the mechanical strength of the stator and reduction of heat generation.

1 is a perspective view of a motor according to a first embodiment of the invention; FIG. 2 is a side cross section showing the motor 10 of FIG. 1 cut along a plane that passes through the central axis J and is perpendicular to the X axis. 2 is an exploded perspective view of the motor 10 of FIG. 1 as seen from the -Z side; FIG. 2 is a perspective view showing a stator 11 of the motor 10 of FIG. 1; FIG. 5 is a perspective view showing the stator 11 of FIG. 4 with a stator case 112 removed; FIG. FIG. 6 is a perspective view showing a state in which a stator core unit 120 is further removed from the state shown in FIG. 5; 5 is a diagram showing a modification of a stator case and an inner diameter member that can be used in place of the stator case 112 and inner diameter member 114 shown in FIG. 4; FIG. FIG. 4 is a diagram showing eddy current loss densities calculated by electromagnetic field analysis; It is a figure showing a stator case concerning a 2nd embodiment of the present invention. It is a figure showing a stator case concerning a 3rd embodiment of the present invention.

Hereinafter, axial gap motors according to embodiments of the present invention will be described with reference to the drawings. It should be noted that, in the drawings below, in order to make each configuration easier to understand, there are cases where the scale, number, etc., of the actual structure and each structure are different.

Also, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is parallel to the axial direction of the central axis J shown in FIG. The Y-axis direction is the vertical direction in FIG. 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, Y-axis direction, and Z-axis direction, the side indicated by the arrows in the drawing is the + side, and the opposite side is the - side.

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 terms "one side" and "the other side" are merely names used for explanation, and do not limit the actual positional relationship and direction. Further, unless otherwise specified, the direction parallel to the central axis J (the Z-axis direction) is simply referred to as the "axial direction", the radial direction about the central axis J is simply referred to as the "radial direction", and the central axis J , that is, the circumference of the central axis J is simply referred to as the "circumferential direction". The side closer to the central axis J in the radial direction is called "radial inner side", and the side farther from the central axis J is called "radial outer side".

In this specification, "extends in the axial direction" means not only the case of extending strictly in the axial direction (Z-axis direction), but also the case of extending in a direction inclined within a range of less than 45° with respect to the axial direction. Also includes In addition, in this specification, "extending in the radial direction" means extending strictly in the radial direction, that is, in a direction perpendicular to the axial direction (the Z-axis direction), and in addition to extending in the radial direction by 45 It also includes cases where it extends in a tilted direction within a range of less than °. "Parallel" includes not only the case of being strictly parallel, but also the case of being tilted within a range of less than 45°. Further, "expanding in a direction perpendicular to the axial direction" means that in addition to expanding strictly in a direction perpendicular to the axial direction (Z-axis direction), 45 Including cases where it spreads in a tilted direction within a range of less than °.

<First embodiment>
FIG. 1 is a perspective view of a motor according to a first embodiment of the invention. A motor 10 in FIG. 1 is an example of an axial gap motor. FIG. 2 is a side cross-sectional view showing the motor 10 of FIG. 1 cut along a plane that passes through the central axis J and is perpendicular to the X-axis.

The motor 10 includes a shaft 14 extending along the central axis J, a stator 11, a frame 12 arranged on one axial side of the stator 11, and a frame 13 arranged on the other axial side of the stator 11. have. Stator 11 has stator case 111 and stator case 112 . Stator case 111 has a bottomed cylindrical shape having a bottom on the other side in the axial direction. Stator case 112 is disc-shaped. The stator 11 is configured by housing a stator core 121 (see FIG. 5) in a space formed in the stator case 111 and the stator case 112 when the stator case 111 and the stator case 112 are combined.

The motor 10 has an inlet 16 through which the coolant flows into the stator 11 and an outlet 15 through which the coolant in the stator 11 flows out. The inlet 16 is provided on the −Y side of the stator 11 and the outlet 15 is provided on the +Y side of the stator 11 . The inlet 16 is fitted in the through hole 111 b of the stator case 111 and the outlet 15 is fitted in the through hole 111 a of the stator case 111 .

The motor 10 has rotors 20 and 21 . The rotor 20 faces the stator 11 in the axial direction and is arranged on one side of the stator 11 in the axial direction. The frame 12 covers the rotor 20 from one side in the axial direction. Frame 12 is fixed to stator case 111 . The rotor 21 axially faces the stator 11 and is arranged on the other side of the stator 11 in the axial direction. The frame 13 covers the rotor 21 from the other side in the axial direction. Frame 13 is fixed to stator case 112 .

The frame 12 has a through hole 12a passing therethrough in the axial direction. The inner diameter member 113, which will be described later in detail, has a through hole 113c extending therethrough in the axial direction. The inner diameter member 114, which will be described later in detail, has a through hole 114a extending therethrough in the axial direction. The frame 13 has a through hole 13a passing therethrough in the axial direction. The shaft 14 passes through the through hole 12a, the through hole 113c, the through hole 114a and the through hole 13a.

The motor 10 has a bearing 22a and a bearing 22b. The bearing 22a is arranged radially inside the through hole 12a. The bearing 22b is arranged radially inside the through hole 13a. The bearings 22a and 22b support the shaft 14 so as to be rotatable along the central axis J. As shown in FIG.

The rotor 20 has a rotor core 20a and magnets 20b. The rotor core 20a is disc-shaped. The magnet 20b is fixed to the surface of the rotor core 20a facing the stator 11 (the surface on the other side in the axial direction). Magnet 20b faces stator 11 with a gap therebetween.
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. The rotor 21 has a rotor core 21a and magnets 21b. The rotor core 21a is disc-shaped. The magnet 21b is fixed to the surface of the rotor core 21a facing the stator 11 (the surface on one side in the axial direction). Magnet 21b faces stator 11 with a gap therebetween. 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 20 a and the rotor core 21 a are fixed to the shaft 14 .

FIG. 3 is an exploded perspective view of the motor 10 of FIG. 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 bolts 17a. The frame 13 is fixed to the other axial side of the stator 11 by bolts 17b.

4 is a perspective view showing the stator 11 of the motor 10 of FIG. 1. FIG. FIG. 5 is a perspective view showing the stator 11 of FIG. 4 with the stator case 112 removed. Stator case 112 has bolt holes 112a into which bolts 17b are fitted. Stator 11 has bolts 115 . Stator case 112 has bolt holes 112b into which bolts 115 are fitted. Stator case 112 is fixed to stator case 111 by bolts 115 . The stator case 111 has a bolt hole (not shown) into which a bolt 17a is fitted, on one side surface in the axial direction. Stator case 111 has bolt holes 111c into which bolts 115 are fitted.

Stator 11 has stator core 121 . One axial end of stator core 121 is an example of a facing portion that faces rotor 20 . The other axial end of stator core 121 is an example of a facing portion that faces rotor 21 . A structure in which the stator core 121 is covered with a bobbin (not shown) and wound with a coil (not shown) 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.

Stator case 112 is made of a metal material. Stator case 112 has an opening 112c through which one axial end of stator core 121 is exposed. The openings 112 c are provided in the same number as the stator cores 121 .

Stator case 112 has a frame portion 112d. The frame portion 112d radially extends from the outer edge of the surface facing the rotor 20 in the axial direction toward the inner edge. A plurality of frame portions 112d are arranged in the circumferential direction. The opening 112c has an outer edge of a surface facing the rotor 20 in the axial direction, one of the plurality of frame portions 112d, a frame portion 112d adjacent to the one frame portion 112d, and the rotor 20 in the axial direction. It consists of being surrounded by the inner edge of the surface to be 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 obtained by cutting at least a portion of the portion surrounding the opening 112c. That is, the cut portion in this case is formed by cutting between the radially inner end of one of the plurality of frame portions 112d and the radially inner end of the frame portion 112d adjacent to this one frame portion 112d. .

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 formed by insert molding, for example. The inner diameter member 114 is an example of a filling section connected to the cut section.

FIG. 6 is a perspective view showing a state in which stator core unit 120 is further removed from the state shown in FIG. Stator case 111 is made of a metal material. Stator case 111 has an opening 111c through which the other axial end of stator core 121 is exposed. The openings 111 c are provided in the same number as the stator cores 121 .

The stator case 111 has a frame portion 111d. The frame portion 111d radially extends 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. A plurality of frame portions 111d are arranged in the circumferential direction. The opening portion 111c is surrounded by an outer edge portion 111a, one of a plurality of frame portions 111d, a frame portion 111d adjacent to this one frame portion 111d, and an inner edge of a surface facing the rotor 21 in the axial direction. It consists 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 obtained by cutting at least a portion of the portion surrounding the opening 111c. That is, the cut portion in this case is formed by cutting between the radially inner end of one of the plurality of frame portions 111d and the radially inner end of the frame portion 112d adjacent to this one frame portion 111d. .

Stator 11 has an inner diameter member 113 . The inner diameter member 113 has an annular portion 113a, which is an annular plate member, and a cylindrical portion 113b, which is a cylindrical member extending from the inner periphery of the annular portion 113a to one side in the axial direction. The annular portion 113a and the cylindrical portion 113b are an integral 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 formed by insert molding, for example. The inner diameter member 113 is an example of a filling section connected to the cut section.

FIG. 7 is a diagram showing a modification 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 FIG. FIG. 7 is a plan view of a stator case 1112 and an inner diameter member 1114 of a modification, viewed from one axial side.

Stator case 1112 is made of a metal material. Stator case 1112 has a frame portion 1112d. The frame portion 1112d has an end portion 1112e at its radial 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 periphery of the inner diameter member 114 has a protrusion 1114b protruding radially outward. The concave portion 1112f and the convex portion 1114b are fitted to each other. The concave portion 1112f and the convex portion 1114b are an example of a fitting portion for fitting the radially inner ends of the plurality of frame portions 1112d and the inner diameter member 1114 as a filling portion. This makes it possible to prevent the frame portion 1112 d and the inner diameter member 1114 from coming off more than the case of the stator case 112 and the inner diameter member 114 . Incidentally, the stator case 111 side can also have the same structure.

FIG. 8 is a diagram showing eddy current loss densities calculated by electromagnetic field analysis. FIG. 8A is a diagram showing the eddy current loss density for an example in which the inner diameter member 114 is not used and the frame portions are connected to each other by metal on the inner diameter side. FIG. 8B is a diagram showing the eddy current loss density for an example in which the inner diameter member 114 is used as shown in FIG.

In the example of FIG. 8A, stator case 2112 is made of metal material. The plurality of frame portions 2112d are connected to each other by a radially inner portion 2113, and are all made of metal, forming an eddy current path surrounding the end of the stator coil. Therefore, in the example of FIG. 8A, the eddy current loss density is high.

In the example of FIG. 8B, the stator case 112 is made of metal material. On the other hand, the inner diameter member 114 is made of a resin material. As a result, no eddy current paths are formed around the ends of the stator coils. Therefore, in the example of FIG. 8(B), the eddy current loss density is lower than in the example of FIG. 8(A). Therefore, it can be seen that the structure of this embodiment greatly reduces the loss.

<Second embodiment>
FIG. 9 is a diagram showing a stator case according to a second embodiment of the 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 FIG. Since other structures are the same as those of the first embodiment, detailed description thereof will be omitted. FIG. 9 is a plan view of the stator case 3112 viewed from one side in the axial direction.

In this embodiment, a stator case 3112 made of a metal material is also used where the inner diameter member 114 was used in the first embodiment. Stator case 3112 is made of a metal material. Stator case 3112 has a frame portion 3112d surrounding an opening through which one axial end of stator core 121 is exposed. Stator case 3112 has an inner diameter portion 3114 . The inner diameter portion 3114 connects the plurality of frame portions 3112d to each other on the inner diameter side.

In this embodiment, a slit 3116 is provided in the frame portion 3112d between the UV phases, and a slit 3117 is provided in the frame portion 3112d between the VW phases. The slits 3116 and 3117 reach the entire circumferential direction of each frame portion 3112d and penetrate in the axial direction. The slits 3116 and 3117 are examples of cut portions obtained by cutting at least a portion of the portion surrounding the opening. That is, the cut portion in this case is formed by cutting the frame portion 3112d radially inward and radially outward.

By providing the slits 3116 and 3117 in this way, the path of the eddy current generated around the opening can be cut off. For example, in the path indicated by dashed arrow A, slits 3116 and 3117 provide eddy current paths. Incidentally, the stator case 111 side can also have the same structure.

In this embodiment, a slit is not provided between the WU phases, so that the inner diameter portion 3114 does not come off from the frame portion 3112d. Therefore, paths around the UVW phase indicated by the dashed-dotted arrow B and around the UVW phase indicated by the dashed-dotted arrow C are connected by a metal material. However, around the UVW phase, the respective magnetic fluxes of the UVW are added, and this large eddy current loop does not occur, which has the effect of reducing losses according to this embodiment.

<Third Embodiment>
FIG. 10 is a diagram showing a stator case according to a third embodiment of the invention. In the second embodiment shown in FIG. 9, since the slits penetrate in the axial direction, it is possible for the cooling liquid flowing into the stator 11 from the inlet 16 to flow out of the slits without reaching the outlet 15. have a nature. In this case, cooling efficiency may decrease. Therefore, in the present embodiment, a plurality of plate-shaped stator cases are stacked to provide a structure in which the slits do not pass through in the axial direction.

In this embodiment, in addition to the stator case 3112 of the second embodiment, a stator case 4112 obtained by rotating the stator case 3112 by 30 degrees in the circumferential direction and a stator case 5112 by rotating the stator case 4112 by 30 degrees in the circumferential direction are used. prepare. FIG. 10A is a plan view of the stator case 3112 viewed from one side in the axial direction. FIG. 10A is a plan view of the stator case 3112 viewed from one side in the axial direction. FIG. 10B is a plan view of the stator case 4112 viewed from one side in the axial direction. FIG. 10C is a plan view of the stator case 5112 viewed from one side in the axial direction. In this embodiment, instead of using the stator case 3112 alone as in the second embodiment, a stator case in which a stator case 3112, a stator case 4112, and a stator case 5112 are laminated in the axial direction is used. This laminated stator case is an example of a lid including a surface facing the rotor 20 in the axial direction. The lid portion is formed by laminating a plurality of plate members (stator case 3112, stator case 4112, and stator case 5112) extending in a direction perpendicular to the axial direction. Lamination may be performed using any known method, such as an adhesive. Since other structures are the same as those of the first embodiment, detailed description thereof will be omitted. Incidentally, the stator case 111 side can also have the same structure.

Stator case 3112 is made of a metal material. Stator case 3112 has a frame portion 3112d surrounding an opening through which one axial end of stator core 121 is exposed. The stator case 3112 is provided with a slit 3116 in the frame portion 3112d between the UV phases and a slit 3117 in the frame portion 3112d between the VW phases.

Stator case 4112 is made of a metal material. Stator case 4112 has a frame portion 4112d surrounding an opening through which one axial end of stator core 121 is exposed. The stator case 4112 is provided with a slit 4118 in the frame portion 4112d between the W and U phases, and with a slit 4116 in the frame portion 4112d between the UV phases.

Stator case 5112 is made of a metal material. Stator case 5112 has a frame portion 5112d surrounding an opening through which one axial end of stator core 121 is exposed. The stator case 5112 is provided with a slit 5117 in the frame portion 5112d between the VW phases and a slit 5118 in the frame portion 4112d between the WU phases.

The slits 3116, 3117, 4116, 4118, 5117, and 5118 are examples of cut portions obtained by cutting at least a portion of the portion surrounding the opening. That is, the cut portion in this case is formed by cutting the frame portion 3112d, 4112d or 5112d radially inward and radially outward.

One cut portion (i.e. slit 3116, 3117, 4116, 4118, 5117 or 5118) of a plurality of plate members (i.e. stator cases 3112, 4112 and 5112) is a plate member different from this one plate member. It overlaps with the frame part which does not have a cutting|disconnection part among several frame parts in an axial direction. For this reason, in the laminated stator case, the slit does not penetrate in the axial direction, and the coolant that has flowed into the stator 11 from the inlet 16 does not flow out from the slit. Outlet 15 is reached.

The present invention is not limited to the above embodiments, and various improvements and design changes may be made without departing from the scope of the present invention. In addition, the embodiments disclosed this time should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents to the scope of the claims.

DESCRIPTION OF SYMBOLS 10... Motor, 11... Stator, 12... Frame, 13... Frame, 14... Shaft, 111... Stator case, 111c... Opening, 112... Stator case, 112c... Opening, 121... Stator core

Claims (7)

An axial gap motor having a stator and a rotor axially facing the stator,
The stator has a plurality of stator cores arranged in a circumferential direction and a stator case housing the stator cores,
The stator core has a facing portion facing the rotor at an axial end,
The stator case is made of a metal material,
The stator case has an opening that exposes the facing portion toward the rotor,
the stator case has a cut portion obtained by cutting at least a portion of a portion surrounding the opening;
axial gap motor. The stator case has a plurality of frame portions arranged in a circumferential direction extending radially from an outer edge toward an inner edge of a surface axially facing the rotor,
The opening includes an outer edge of a surface axially facing the rotor, one of the plurality of frame portions, a frame portion adjacent to the one frame portion, and a surface axially facing the rotor. is bounded by the inner edge of
The axial gap motor according to claim 1. It further has a filling part connected to the cutting part,
The filling part is made of a resin material,
3. The axial gap motor according to claim 2. The cut portion is formed by cutting between a radially inner end of one of the plurality of frame portions and a radially inner end of a frame portion adjacent to the one frame portion.
The axial gap motor according to claim 3. Having a fitting portion that fits the radially inner ends of the plurality of frame portions and the filling portion,
The axial gap motor according to claim 4. The cut portion is formed by cutting the frame portion radially inwardly and radially outwardly,
3. The axial gap motor according to claim 2. The stator case has a lid portion including a surface axially facing the rotor,
The lid portion is formed by laminating a plurality of plate members extending in a direction orthogonal to the axial direction,
each of the plurality of plate members has the plurality of frame portions,
each of the plurality of plate members has the cut portion in at least one of the plurality of frame portions;
The cut portion of one of the plurality of plate members axially overlaps with a frame portion without the cut portion among the plurality of frame portions of another plate member different from the one plate member,
The axial gap motor according to claim 6.

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