Axial gap motor
By using printed wiring substrates and gap structures in axial gap type motors, the lack of distributed winding in volume occupancy and insulation endurance is solved, higher accuracy and productivity are achieved, and the flattening of the motor is promoted and Characteristic stabilization.
Patent Information
- Application Number
- CN202380029936.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-23
- Filing Date
- 2023-03-10
- Publication Date
- 2024-12-17
AI Technical Summary
The existing axial gap motors with distributed winding have insufficient volume occupancy and insulation endurance, and are difficult to achieve flattening and accuracy improvement.
By using a printed wiring substrate, a plurality of phase substrates are laminated in the axial direction and a gap is provided therebetween to form a coiled winding pattern, ensuring sufficient space distance and filling in insulating materials to improve insulation endurance and heat dissipation. At the same time, reduce assembly complexity.
The volume occupancy and insulation endurance of distributed winding are improved, the assembly process and number of parts are reduced, productivity is improved, and the flattening and characteristic stabilization of the motor is promoted.
Smart Images
Figure CN119156760A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an axial gap motor, and more particularly to an axial gap motor having a distributed winding motor coil. Background Art
[0002] Patent documents 1 and 2 propose distributed winding axial gap motors. For example, in the axial gap motor disclosed in Patent document 1 (FIG. 27 and FIG. 28), the motor coils of the three phases are distributedly wound over a plurality of salient pole teeth, thereby reducing the spatial harmonics of the magnetic flux and achieving a reduction in vibration and noise. On the other hand, Patent document 3 proposes an axial gap motor with concentrated winding motor coils, wherein the stator has a magnetic body and a plurality of wiring substrates stacked with the magnetic body from the axial direction, and a coil winding pattern is formed on each wiring substrate.
[0003] Prior art literature
[0004] Patent Literature
[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-193838
[0006] Patent Document 2: Japanese Patent Application Publication No. 2006-187091
[0007] Patent Document 3: Japanese Patent Application Publication No. 2018-93650 Summary of the invention
[0008] Regarding the motor with distributed winding, the rotating magnetic field formed by the motor stator is close to a sine wave, and the rotation characteristics and output performance of the motor are better than those of concentrated winding. However, it is difficult to improve the volume occupancy rate of distributed winding compared with concentrated winding. In other words, there is no winding machine (insertion machine) dedicated to distributed winding for axial gap type motors, and the main winding technology. Therefore, as the current situation of distributed winding, winding is performed by manual work, and therefore the current situation is that the accuracy (volume occupancy rate) is low.
[0009] In addition, if the coil windings are arranged across a plurality of cores (salient pole teeth) formed on the motor stator, the coil windings of each phase are arranged to overlap in the axial direction (in the direction of the motor center axis). As a result, the axial length of the motor stator increases compared to the case of concentrated winding, which is not conducive to the flattening that is an advantage of the axial gap type motor. In order to suppress the increase in axial length, for example, as described in Patent Document 3, it is considered to stack a wiring substrate having a coil winding pattern formed of copper foil in the axial direction. However, when the substrate is stacked with the coil winding pattern of the copper foil exposed on the surface as it is, the spatial distance cannot be ensured, the insulation withstand voltage characteristics required for the motor deteriorate, and a short circuit may result.
[0010] In view of the above problems, an object of the present invention is to provide a flat axial gap motor having a distributed winding motor coil with a high volume occupancy rate and achieving improved dielectric strength.
[0011] The present invention is an axial gap type motor including a motor rotor and a motor stator which are opposed to each other with a certain gap in the axial direction, and is characterized in that:
[0012] The motor rotor comprises: a rotor disk; and a rotor magnet, which is arranged on the rotor disk.
[0013] The motor stator includes: a stator core; a printed wiring substrate stacked on the stator core in the axial direction; and a plurality of motor coils corresponding to the plurality of phases formed on the printed wiring substrate.
[0014] The stator core end surface of the stator core on which the printed wiring substrate is stacked is arranged, and the salient pole teeth protruding from the stator core end surface in the axial direction are arranged at a certain angular interval in the circumferential direction centered on the motor central axis.
[0015] The printed wiring substrate is a laminated substrate including: a plurality of phase substrates which are laminated with a certain inter-substrate gap in the axial direction; and a gap forming member which is located between the phase substrates adjacent to each other in the axial direction in order to ensure the inter-substrate gap.
[0016] The phase substrates each include: an insulating substrate; a plurality of salient pole tooth through holes formed in the insulating substrate, the salient pole teeth being inserted through the salient pole tooth through holes; and the motor coil belonging to one phase assigned to the phase substrate.
[0017] The motor coil of each phase is a distributed winding coil winding pattern formed on the insulating substrate.
[0018] In the present invention, a distributed winding coil winding pattern is formed on the surface of a printed wiring substrate (PCB substrate) using a conductive metal foil such as copper foil, thereby increasing the volume occupancy of the distributed winding. As in the case of conventional distributed winding, a winding structure spanning a plurality of salient pole teeth uses a printed wiring substrate (PCB substrate), thereby suppressing the increase in size caused by the overlap of the coil winding patterns in the length direction (axial direction), which is conducive to the flattening of the motor.
[0019] In addition, regarding the printed wiring substrate, a gap forming member is arranged between adjacent phase substrates, and the phase substrates of each phase are stacked in a state where a certain inter-substrate gap is formed between them by the gap forming member. Unlike the case where different phase substrates are directly stacked in the axial direction on the surface of the phase substrate having a coil winding pattern of a metal foil formed on the surface, a sufficient space distance can be ensured between the phase substrates of each phase. The insulation resistance required by the motor can be maintained, and the risk of winding short circuit is also reduced.
[0020] Furthermore, the gap between the substrates can be easily filled with insulating resin material (molding material, varnish, etc.) in accordance with the spatial shape of the gap, thereby achieving improved insulation resistance, improved heat dissipation (heat generation of the coil winding pattern), and fixation of the phase substrates to each other.
[0021] Furthermore, the printed wiring substrate is a laminated substrate in which a plurality of phase substrates, for example, three phase substrates of U phase, V phase, and W phase are laminated in the axial direction. In the assembly operation, the phase substrates only need to be laminated in a state of being positioned in the circumferential direction. As a result, the operation process of distributed winding, which is very labor-intensive, can be reduced, and the assembly man-hours and the number of parts can also be reduced, thereby improving productivity. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1A This is a schematic structural diagram showing an axial gap motor to which the present invention is applied.
[0023] Figure 1B It is a perspective view showing a motor stator and a motor rotor.
[0024] Figure 1C is a side view showing a motor stator.
[0025] Figure 1D This is a plan view of a phase substrate of a printed wiring substrate constituting a motor stator.
[0026] Figure 1E The diagram is a perspective view showing three phase substrates and a spacer constituting a printed wiring substrate of a motor stator, and shows a state in which the phase substrates are separated.
[0027] Figure 2 It is a perspective view showing a stator core of a motor stator.
[0028] Figure 3 (A) is a perspective view showing a phase substrate composed of a first substrate and a second substrate. Figure 3 (B) is a perspective view showing a state where the first substrate and the second substrate are separated.
[0029] Figure 4The diagram is a perspective view showing a stator core and a printed wiring board constituting a motor stator, and shows a state where three phase substrates constituting the printed wiring board are separated, and illustration of a spacer is omitted.
[0030] Figure 5 It is an explanatory diagram showing an example of a neutral point wiring pattern formed on three-phase substrates.
[0031] Figure 6 This is a wiring diagram showing an example of a connection circuit of a motor coil in the case of a three-phase motor.
[0032] Figure 7 This is a schematic structural diagram showing another example of the axial gap motor. DETAILED DESCRIPTION
[0033] Hereinafter, the axial gap motor with distributed winding involved in the embodiment of the present invention will be described with reference to the accompanying drawings. The embodiment described below shows an example of the present invention, and the present invention is not limited to the embodiment. For example, the number of phases, the number of poles, the number of slots, the shape of the magnets, and the shape of the slots are not limited to the number and shape of the following embodiments. In addition, the winding method of the distributed winding can be any of coaxial winding, overlapping winding, and wavy winding.
[0034] Figure 1A 1 is a schematic diagram showing the structure of an axial gap type motor with distributed winding. The axial gap type motor 1 (hereinafter referred to as "motor 1") is a three-phase motor with 8 poles and 36 slots in this example. Figure 1A As shown, it comprises: a hollow motor shaft 2; a motor rotor 4, which is coaxially fixed to the above-mentioned hollow motor shaft 2; a motor stator 5, which is coaxially opposite to the motor rotor 4 with a certain gap in the axial direction along the central axis 1a; and a motor housing 6, which is used to fix the motor stator 5.
[0035] Figure 1B 1 is a perspective view showing the motor rotor 4 and the motor stator 5, and is shown in a state where the gap between the motor rotor 4 and the motor stator 5 is enlarged. As shown in the figure, the motor rotor 4 includes: a ring-shaped rotor disk 41, which is made of a ferromagnetic body such as iron; and magnets 42, which are attached to the rotor disk 41. In this example, eight groups of magnets 42 are buried in the rotor disk 41 at a certain angle interval in the circumferential direction.
[0036] Figure 1C is a side view showing the motor stator 5. Figure 1B , Figure 1CTo explain, the motor stator 5 includes: a plate-shaped stator core 10 made of a ferromagnetic body; and a ring-shaped printed wiring board 20 (PCB board) coaxially stacked on the end surface 11 of the stator core 10 on the motor rotor 4 side. The printed wiring board 20 is printed with motor coils 30 corresponding to the U phase, V phase, and W phase, and other circuits.
[0037] like Figure 1C As shown in FIG. 1 , the printed wiring substrate 20 is a laminated substrate having a structure in which a plurality of phase substrates 21 of the same structure are laminated coaxially in the axial direction with a spacer 26 for forming a gap between the substrates. In this example, the three phase substrates 21 are laminated coaxially in the axial direction with a certain gap G between the substrates formed by the spacer 26. Figure 1C As shown in the frame of the virtual line in the middle, the printed wiring board 20 portion of the motor stator 5 of this structure is covered with a mold member 27 made of an insulating resin.
[0038] Figure 1D It is a plan view of the phase substrate 21 of the printed wiring substrate 20 constituting the motor stator 5 . Figure 1E 3D is a perspective view of three phase substrates 21 and spacers 26 constituting the printed wiring substrate 20, and the phase substrates 21 are shown in a separated state. As shown in the above figure, the three phase substrates 21 are respectively a U-phase substrate 21U on which a U-phase motor coil 30U is formed, a V-phase substrate 21V on which a V-phase motor coil 30V is formed, and a W-phase substrate 21W on which a W-phase motor coil 30W is formed. In addition, in this example, between the U-phase substrate 21U stacked on the stator core 10 and the V-phase substrate 21V stacked thereon, for example, six spacers 26 are sandwiched and arranged at equal angles in the circumferential direction. Similarly, between the V-phase substrate 21V and the W-phase substrate 21W above it, for example, six spacers 26 are also sandwiched. The spacers 26, which are components for forming gaps between substrates, are manufactured as components different from the phase substrates, and are arranged between the phase substrates. Alternatively, the spacer 26 is integrally formed on a part of the phase substrate 21 as a protrusion for forming the gap between substrates.
[0039] The structure of each part of the motor 1 will be described in more detail.
[0040] Figure 21 is a perspective view showing the stator core 10 of the motor stator 5. The stator core 10 includes: a plate-shaped back yoke 12, which is made of, for example, a sintered body or a pressed powder body and has a circular opening formed in the center; and salient pole teeth 13 formed on an end surface 11, which is an end surface on the motor rotor side of the back yoke 12. The salient pole teeth 13 protrude in the axial direction and are arranged at a certain angle interval in the circumferential direction with the central axis 1a as the center. In this example, salient pole teeth 13 corresponding to 36 slots, which is an integral multiple of the phase number 3, are formed.
[0041] Figure 3 (A) is a perspective view showing one phase substrate 21 (21U, 21V, 21W) constituting the printed wiring substrate 20. Figure 3 (B) is a stereoscopic view showing a state where two insulating substrates constituting the phase substrate 21 are separated. As shown in these figures, the phase substrate 21 is a two-layer substrate in which two insulating substrates 22 (1) and 22 (2) of the same shape are stacked in the axial direction. Each insulating substrate 22 (1) and 22 (2) is formed into a disc shape with a circular opening formed in the center, and is formed with a salient pole tooth through hole 23 that penetrates in its thickness direction (axial direction). There are 36 salient pole tooth through holes 23 formed at certain angular intervals in the circumferential direction. In addition, a plurality of motor coils 30 are arranged at certain angular intervals on the surface (surface on the motor rotor side) of the insulating substrates 22 (1) and 22 (2). The motor coil 30 is a distributed winding coil, which is defined by a coil winding pattern made of copper foil. In this example, the coil winding pattern printed in a manner to surround four adjacent slots is formed at 6 locations at equal angular intervals in the circumferential direction.
[0042] The two insulating substrates 22 (1) and 22 (2) of this structure are stacked and integrated in the axial direction in a state where they are offset by three slots in the circumferential direction, thereby forming a phase substrate 21. Figure 3 As shown in FIG. 1B , the current flowing in the motor coil 30 of the upper insulating substrate 22 (2) is in the CCW direction as indicated by the solid arrow, and the current flowing in the motor coil 30 of the lower insulating substrate 22 (1) is in the opposite CW direction as indicated by the dotted arrow. In addition, a through hole (not shown) is formed in the insulating substrate 22 (2), and the coil winding patterns formed on both insulating substrates are connected by means of the through hole.
[0043] Figure 4This is an explanatory diagram showing the stacking state of three phase substrates 21, showing the phase substrates 21 separated from each other, and omitting the illustration of the spacer 26 between the phase substrates 21. On the end surface 11 of the back yoke 12 of the stator core 10, three phase substrates 21 of the same structure are coaxially stacked in the axial direction and integrated to form a printed wiring substrate 20. The three phase substrates 21 are stacked in a state offset by one slot in the circumferential direction. In this example, there are 36 slots, so they are offset in the circumferential direction by a mechanical angle of 10° (=360° / 36 slots).
[0044] As described above, the phase substrate 21 stacked on the end surface 11 of the back yoke 12 is a U-phase substrate 21U, and its motor coil 30 is a U-phase motor coil 30U. The phase substrate 21 stacked on the U-phase substrate 21U is a V-phase substrate 21V printed with a V-phase motor coil 30V, and the phase substrate 21 stacked on it is a W-phase substrate 21W printed with a W-phase motor coil 30W. In addition, Figure 4 Although not shown in the figure, coil winding patterns of motor coils 30U, 30V, 30W are formed on each phase substrate 21U, 21V, 21W, and a neutral point wiring pattern is also formed for wiring the coil winding patterns of each phase U, V, W at a neutral point.
[0045] Figure 5 : This is an explanatory diagram showing the neutral point wiring pattern formed on the phase substrate 21 (21U, 21V, 21W). On the surface (the surface on the motor rotor 4 side) of the phase substrate 21 (21U, 21V, 21W) of each phase, a neutral point wiring pattern 24 (24U, 24V, 24W) is formed of copper foil together with a coil winding pattern (not shown). The neutral point wiring pattern 24 is a wiring pattern of a predetermined length extending in the circumferential direction, and in this example, it is a wiring pattern in the shape of an arc opened at a certain angle with the central axis 1a as the center. In addition, a plurality of through holes 25 penetrating in the thickness direction are formed in the phase substrate 21. The through holes 25 are formed along the neutral point wiring pattern 24 at an angular interval corresponding to the offset amount in the circumferential direction of each phase substrate 21.
[0046] When three phase substrates 21 of the same structure are stacked in the axial direction to form the printed wiring substrate 20, one through hole 25 of the neutral point wiring pattern 24U, 24V, 24W of each phase substrate 21U, 21V, 21W is aligned. After the phase substrates 21U, 21V, 21W are stacked, the coil winding pattern of each phase is connected by soldering, welding, etc. through the three through holes 25 at the aligned positions. The motor coil 30 of each phase is connected in a star shape with the through hole 25 as the neutral point.
[0047] Figure 62 shows an example of a connection circuit of the motor coil 30 of three phases (U, V, W). A wiring pattern for circuit connection such as a crossover connecting the coil winding patterns of the motor coil 30 of each phase is also patterned by copper foil or the like on each phase substrate 21. As described above, the coil winding patterns of each phase are connected to each other at the neutral point (the position of the through hole that coincides with each other) by means of the neutral point connection pattern 24 of each phase.
[0048] As described above, the motor 1 of this example uses a printed wiring board 20 which is a laminate of phase substrates 21U, 21V, 21W of U, V, W phases on which motor coils 30U, 30V, 30W of each phase are defined by a coil winding pattern of copper foil. Phase substrates 21 (21U, 21V, 21W) of the same structure are laminated on the back yoke 12 in accordance with the number of phases to form the motor stator 5. In addition, the phase substrate 21 (21U, 21V, 21W) of each phase is a two-layer integrated structure in which two insulating substrates 22 (1) and 22 (2) are laminated. Distributed winding is achieved by offsetting the motor coil 30 (coil winding pattern) in the circumferential direction between the insulating substrates 22 (1) and 22 (2) and reversing the direction of current flow.
[0049] In this way, a distributed winding coil winding pattern is formed by copper foil or the like on the surface of the printed wiring substrate 20. Therefore, the volume occupancy of the distributed winding can be increased, and the degree of freedom of winding design can be increased. As the distributed winding, any of coaxial winding, overlapping winding, and wave winding can be adopted. In addition, the occurrence of damage and burning of the coil can also be suppressed.
[0050] In addition, similar to the case of conventional distributed winding, the winding structure spanning a plurality of salient pole teeth 13 uses the printed wiring board 20. Therefore, the size increase due to the overlap of the coil winding patterns in the longitudinal direction (axial direction) can be suppressed, which contributes to the flattening of the motor.
[0051] Furthermore, since the distributed winding motor coil does not have the disadvantage of enlarging the coil ends, it is not necessary to ensure the arrangement space of the motor coil on the inner circumference side or the outer circumference side of the motor stator. Therefore, for example, a motor with a larger hollow diameter can be realized.
[0052] In addition, the copper foil pattern of the printed wiring board is more accurate than manual winding. Therefore, the deviation of the induced voltage value, the maximum value (PP) of the waveform, and the effective value (rms) is reduced. As a result, it can contribute to the stabilization of motor characteristics (variation reduction).
[0053] Furthermore, the number of parts can be greatly reduced, and the assembly man-hours can also be reduced. That is, the printed wiring substrate is a laminated substrate in which a plurality of phase substrates, for example, three phase substrates of U phase, V phase, and W phase are laminated in the axial direction. In the assembly operation, it is sufficient to laminate the phase substrates in a state of being positioned in the circumferential direction. In addition, the phase substrates can be set as substrates of the same structure. As a result, the operation process of distributed winding, which is very labor-intensive, can be reduced, and the assembly man-hours and the number of parts can also be reduced, thereby improving productivity.
[0054] On the other hand, a neutral point wiring pattern is formed together with the coil winding pattern of the motor coil of each phase on each phase substrate 21. When each phase substrate 21 is stacked, one through hole of each phase is positioned relative to each other. The coil winding pattern of each phase is connected via the through hole with this position as the neutral point.
[0055] In the conventional connection of the neutral point of a three-phase motor, the ends of the coil windings are connected in the following manner. That is, usually, regardless of distributed winding or concentrated winding, the positions of the ends of the coil windings of each phase are sometimes inconsistent. Therefore, when the coil windings of each phase are connected at the neutral point, it is necessary to partially change the length of each coil winding in terms of design or manufacturing, or to use different wiring components for supplementary connection.
[0056] (a) Adjust the length of the coil wire for each phase and connect it at one location (soldering, welding, etc.)
[0057] (b) Use other wiring components such as bus bars to connect
[0058] In the case of (a), there are problems such as complicated manufacturing conditions, difficulty in aligning the neutral point, and deviation in the neutral point position. In the case of (b), there are problems such as an increase in the number of parts and wiring at multiple locations, which leads to increased costs.
[0059] In this example, as described above, a neutral point wiring pattern of a predetermined length is formed in the circumferential direction on each phase substrate in consideration of the stacking state of each phase substrate, and through holes are formed at a plurality of locations along the neutral point wiring pattern. Thus, the substrates of each phase can be made common, and the operation of wiring the coil winding patterns of each phase at the neutral point can be performed simply and with high precision.
[0060] In addition, regarding the motor 1 of this example, the phase substrates 21U, 21V, and 21W of each phase are stacked by sandwiching a spacer 26. When the copper foil patterns exposed on the surface of the substrates are overlapped as they are, there is no spatial distance, and the insulation withstand voltage characteristics required by the motor are significantly deteriorated, which may cause a short circuit. In this example, by sandwiching the spacer 26 between the phase substrate 21U and the phase substrate 21V, a certain gap G between the substrates can be ensured. Similarly, by sandwiching the spacer 26 between the phase substrate 21V and the phase substrate 21W, a certain gap G between the substrates can be ensured.
[0061] Thus, by providing a gap (space) between the phase substrates, it is possible to improve the insulation resistance. In addition, by providing a gap (space) between each phase substrate, it is possible to easily fill the insulating resin material (molding material, varnish, etc.) between the phase substrates according to the shape of the gap. As a result, it is possible to improve the insulation resistance and the heat dissipation (heat generation of the coil winding pattern), and it is possible to simultaneously fix the phase substrates to each other.
[0062] (Other embodiments)
[0063] The motor 1 is an example of a three-phase motor with 8 poles and 36 slots, but as mentioned above, the number of poles and slots is not limited to the above example. In addition, the shape of the magnet and slot is not limited to the above example, and various shapes and structures can be used.
[0064] Furthermore, if the torque needs to be increased, the motor stator of the above structure can be formed into a multi-stage structure in the axial direction. Figure 7 In the distributed winding axial gap motor 1A shown, the motor stators 5 and the motor stators 5A having the same structure are symmetrically arranged on both sides of the motor rotor 4. Similarly, the combination of the motor rotor and the motor stator may be provided in more stages.
Claims
1. An axial gap motor, comprising a motor rotor and a motor stator which are opposed to each other with a certain gap in the axial direction, characterized in that: The motor rotor comprises: a rotor disk; and a rotor magnet disposed on the rotor disk. The motor stator includes: a stator core; a printed wiring substrate stacked on the stator core in the axial direction; and a plurality of motor coils corresponding to the plurality of phases formed on the printed wiring substrate. The stator core end surface on which the printed wiring substrate is stacked is provided on the stator core, and salient pole teeth protruding from the stator core end surface in the axial direction are arranged at a certain angular interval in a circumferential direction centered on the motor central axis. The printed wiring substrate is a laminated substrate including: a plurality of phase substrates which are laminated with a certain inter-substrate gap in the axial direction; and a gap forming member which is located between the phase substrates adjacent to each other in the axial direction in order to ensure the inter-substrate gap. The phase substrates each include: an insulating substrate; a plurality of salient pole tooth through holes formed in the insulating substrate, the salient pole teeth being inserted through the salient pole tooth through holes; and the motor coil belonging to one phase assigned to the phase substrate. The motor coil of each phase is a distributed winding coil winding pattern formed on the insulating substrate.
2. The axial gap motor according to claim 1, characterized in that: The gap forming member is a substrate protrusion that is formed integrally on the insulating substrate of one or both of the phase substrates that are adjacent in the axial direction and that protrudes in the axial direction.
3. The axial gap motor according to claim 1, characterized in that: The insulating substrate of each of the phase substrates includes a first substrate and a second substrate stacked in the axial direction. The motor coil of each phase includes: a first coil winding pattern of distributed winding formed on a surface of the first substrate on the side opposite to the second substrate; and a second coil winding pattern of distributed winding formed on a surface of the second substrate on the first substrate side. The first coil winding pattern and the second coil winding pattern are formed at positions relatively shifted at a certain angle in the circumferential direction.
4. The axial gap motor according to claim 3, characterized in that: The multiphases are three phases of U phase, V phase and W phase. The three phase substrates are stacked in a state of being shifted at a certain angle in the circumferential direction so as to function as a U-phase substrate, a V-phase substrate, and a W-phase substrate, respectively.
5. The axial gap motor according to claim 4, characterized in that: The U-phase substrate, the V-phase substrate, and the W-phase substrate each include: a neutral point wiring pattern composed of a conductive metal foil and extending in a circumferential direction; and through holes formed at a plurality of locations along the neutral point wiring pattern, When the U-phase substrate, the V-phase substrate, and the W-phase substrate are stacked, one through hole of the U-phase substrate, one through hole of the V-phase substrate, and one through hole of the W-phase substrate coincide with each other to define a neutral point.
6. The axial gap motor according to claim 1, characterized in that: The axial gap motor includes a first motor stator and a second motor stator as the motor stator. The first motor stator and the second motor stator are opposed to the motor rotor from both sides in the axial direction.