Stator structure in rotating electric machines

Abstract

To provide a stator structure in a rotary electric machine which can increase the amount of interlinkage magnetic fluxes which are interlinked with a coreless coil in a generated rotary magnetic field.SOLUTION: The stator structure in a rotary electric machine according to an embodiment includes an inside coil layer and an outside coil layer. In the inside coil layer, a plurality of coreless inside coils are arranged in a circumferential direction. In the outside coil layer, a plurality of coreless outside coils are arranged in a circumferential direction on the outside of the inside coil layer separately from the inside coils. The coil pitches of each inside coil and each outside coil are at least the angle of dividing 360° by the total number of the inside coils and the outside coils.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to a stator structure in a rotating electrical machine.

Background Art

[0002] Rotating electrical machines such as motors and generators include a stator and a rotor. In a motor, a rotating magnetic field is generated by applying a voltage to the coils of the stator. Then, the generated rotating magnetic field rotates the rotor, or an electromotive force is induced in the rotor by the rotating magnetic field, and the induced electromotive force rotates the rotor. In a generator, a voltage (electromotive force) is induced in the coils of the stator by the rotating magnetic field generated by rotating the rotor. In such rotating electrical machines as motors and generators, from the viewpoint of weight reduction, etc., a coreless coil may be used as the stator coil. In this case, in the stator, a plurality of coreless coils are arranged side by side in the circumferential direction. The coils of a normal motor are provided with a core that serves as a path for the magnetic flux that links them, but there is a method that does not use a core, and generally this method is called coreless (non-core), and a coil that adopts the coreless method is called a coreless coil. Since a coreless motor has no core, it is characterized by being lighter than a normal motor.

[0003] In a rotating electrical machine in which a coreless coil is used for the stator as described above, it is required to increase the amount of linked magnetic flux that links the stator coil in the generated rotating magnetic field by, for example, increasing the coil pitch of each stator coil. For example, in a motor in which a coreless coil is used for the stator, by increasing the amount of linked magnetic flux with the coil in the rotating magnetic field generated by applying a voltage to the stator coil, it is required to increase the torque for rotating the rotor. Also, in a generator in which a coreless coil is used for the stator, by increasing the amount of linked magnetic flux with the coil in the rotating magnetic field generated by rotating the rotor, it is required to increase the voltage induced in the coil.

Prior Art Documents

[0004] [Patent Document 1] Japanese Patent Application Publication No. 3-112345 [Patent Document 2] Japanese Patent Publication No. 2019-122230 [Patent Document 3] International Publication No. 2007 / 032472 [Overview of the project] [Problems that the invention aims to solve]

[0005] The problem that this invention aims to solve is to provide a stator structure for a rotating electric machine that can increase the amount of magnetic flux linkage that links with a coreless coil in the generated rotating magnetic field. [Means for solving the problem]

[0006] According to the embodiment, the stator structure in a rotating electric machine comprises an inner coil layer and an outer coil layer. The inner coil layer comprises a plurality of coreless inner coils, which are arranged circumferentially. The outer coil layer comprises a plurality of coreless outer coils, which are arranged circumferentially on the outer circumference of the inner coil layer without contacting the inner coils. In a rotating electric machine, the rotor is rotated by utilizing the rotating magnetic field generated by applying voltage to the inner and outer coils, or by inducing voltage in the inner and outer coils by the rotating magnetic field generated by the rotation of the rotor. The coil pitch of each of the inner and outer coils is greater than or equal to the angle obtained by dividing 360° by the total number of inner and outer coils. The coil pitch of each outer coil is different from the coil pitch of each inner coil. The coil pitch of each of the first coils, which is located closer to the rotor among the inner and outer coils, is larger than that of each of the second coils, which is located further away from the rotor among the inner and outer coils. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing the configuration of the electric motor according to the first embodiment, in a cross-section parallel or substantially parallel to the axial direction of the electric motor. [Figure 2]Figure 2 is a schematic diagram showing the configuration of the electric motor according to the first embodiment, viewed from one side in the axial direction of the electric motor. [Figure 3] Figure 3 is a schematic cross-sectional view showing the configuration of the electric motor according to the first embodiment, in a cross-section perpendicular or substantially perpendicular to the axial direction of the electric motor. [Figure 4] Figure 4 is a schematic perspective view showing any one of the inner coil and outer coil in the electric motor according to the first embodiment. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings.

[0009] (First Embodiment) First, a first embodiment will be described as an example of an embodiment. In the first embodiment, an electric motor 1 will be described as an example of a rotating electric machine. Figures 1 to 3 show the configuration of the electric motor 1 according to the first embodiment. The electric motor 1 is, for example, a permanent magnet motor. As shown in Figures 1 to 3, the electric motor 1 comprises a rotor 2 and a stator 3. The rotor 2 is rotatable relative to the stator 3 about a rotation axis P.

[0010] In electric motor 1, the direction along the rotation axis P is defined as the axial direction (indicated by arrows A1 and A2). In electric motor 1, the direction around the rotation axis P is defined as the circumferential direction (indicated by arrows C1 and C2). In electric motor 1, the direction that intersects (is perpendicular or nearly perpendicular to) both the axial and circumferential directions is defined as the radial direction (indicated by arrows R1 and R2). In electric motor 1, the side approaching the rotation axis P in the radial direction is the inner circumference side, and the side moving away from the rotation axis P in the radial direction is the outer circumference side. Figure 1 schematically shows a cross-section of electric motor 1 parallel or nearly parallel to the axial direction. Figure 2 schematically shows the electric motor 1 viewed from one side in the axial direction, and Figure 3 schematically shows a cross-section of electric motor 1 perpendicular or nearly perpendicular to the axial direction.

[0011] In the example shown in Figures 1 to 3, the rotor 2 is positioned on the inner circumference side of the stator 3, which forms the stator structure of the electric motor 1. The stator 3 surrounds the rotor 2 from the outer circumference side of the electric motor 1, over its entire circumference in the circumferential direction. The rotor 2 is connected to the stator 3 in a manner that allows it to rotate around the axis of the rotation shaft P. The rotor 2 is connected to the stator 3 via bearings or the like (not shown).

[0012] In the example shown in Figures 1 to 3, the rotor 2 comprises a yoke 5 and a plurality of magnets (permanent magnets) 6. The central axis of the yoke 5 is coaxial with or approximately coaxial with the rotation axis P. In the rotor 2, each of the magnets 6 is fixed to the outer surface of the yoke 5, and the plurality of magnets 6 are arranged in a line on the outer surface of the yoke 5 in the circumferential direction of the motor 1. In the rotor 2, the plurality of magnets 6 arranged in the circumferential direction of the motor 1 form a ring shape or approximately ring shape with the rotation axis P as the center or approximately the center.

[0013] The stator 3 comprises an inner coil layer 7 and an outer coil layer 8. Each of the inner coil layer 7 and the outer coil layer 8 is formed in a ring shape or substantially ring shape with the rotation axis P as its center or substantially its center. Each of the inner coil layer 7 and the outer coil layer 8 surrounds the rotor 2 from the outer circumferential side of the motor 1 over the entire circumference in the circumferential direction of the motor 1. In the stator 3, the outer coil layer 8 is formed on the outer circumferential side of the motor 1 relative to the inner coil layer 7. The outer coil layer 8 surrounds the inner coil layer 7 from the outer circumferential side of the motor 1 over the entire circumference in the circumferential direction of the motor 1.

[0014] The inner coil layer 7 comprises a plurality of inner coils 11, and the outer coil layer 8 comprises a plurality of outer coils 12. In the inner coil layer 7, the plurality of inner coils 11 are arranged in a line in the circumferential direction of the electric motor 1. In the stator 3, the plurality of inner coils 11 arranged in the circumferential direction of the electric motor 1 form a ring shape or a substantially ring shape with the rotation axis P as the center or substantially center. In the outer coil layer 8, the plurality of outer coils 12 are arranged in a line in the circumferential direction of the electric motor 1. In the stator 3, the plurality of outer coils 12 arranged in the circumferential direction of the electric motor 1 form a ring shape or a substantially ring shape with the rotation axis P as the center or substantially center.

[0015] Due to the configuration described above, in the stator 3, multiple outer coils 12 are arranged in a line in the circumferential direction of the motor 1 on the outer circumference of the inner coil layer 7, which is composed of multiple inner coils 11. Therefore, the ring shape or substantially ring shape formed by the multiple outer coils 12 surrounds the ring shape or substantially ring shape formed by the multiple inner coils 11 from the outer circumference of the motor 1 over its entire circumference. In addition, each of the outer coils 12 has a gap between it and the inner coils 11 of the inner coil layer 7 in the radial direction of the motor 1. For this reason, each of the outer coils 12 is arranged so as not to be in contact with any of the inner coils 11.

[0016] Each of the inner coil 11 and the outer coil 12 is formed by winding coil wire. Each of the coil windings of the inner coil 11 and the outer coil 12 is conductive and is formed from, for example, a conductive metal. Each of the coil windings of the inner coil 11 and the outer coil 12 is formed from, for example, copper, aluminum, and iron. The coil windings of the inner coil 11 and the outer coil 12 may be formed from the same material relative to each other, or they may be formed from different materials relative to each other. Furthermore, each of the inner coil 11 and the outer coil 12 is a coreless coil without an iron core. Therefore, the electric motor 1 is a coreless motor, etc., in which the inner coil 11 and the outer coil 12, which are the coils of the stator 3, are coreless.

[0017] In this embodiment, the rotor 2 is positioned on the inner circumference side of the stator 3. Of the two types of coils, the inner coil 11 and the outer coil 12, the inner coil 11 is the first coil, positioned closer to the rotor 2. The outer coil 12 is the second coil, positioned further away from the rotor 2.

[0018] In the electric motor 1, voltage can be applied to the inner coil 11 and the outer coil 12, and a magnetic field is generated by applying voltage to the inner coil 11 and the outer coil 12. Then, by applying voltage to the inner coil 11 and the outer coil 12 or the like and changing the magnetic field generated by the inner coil 11 and the outer coil 12 over time, the rotor 2 rotates around the axis of the rotation axis P. Therefore, in the present embodiment, the rotor 2 rotates due to the rotating magnetic field generated by applying voltage to the inner coil 11 and the outer coil 12.

[0019] In an example, three-phase electric power with different phases from each other is supplied to the stator 3. In this case, as the inner coil 11, one or more inner coils 11U of the U phase, inner coils 11V of the V phase, and inner coils 11W of the W phase are provided respectively, and as the outer coil 12, one or more outer coils 12U of the U phase, outer coils 12V of the V phase, and outer coils 12W of the W phase are provided respectively. In an example such as FIGS. 1 to 3, two inner coils 11U, 11V, 11W are provided respectively, and two outer coils 12U, 12V, 12W are provided respectively. For this reason, the number of coils provided in the stator 3, that is, the total number of the inner coil 11 and the outer coil 12 is 12.

[0020] In the stator 3, the inner coil 11U and the outer coil 12U of the U phase are electrically connected in series or in parallel to each other via electrical wiring (not shown) or the like. Then, a voltage of the U phase is applied to the inner coil 11U and the outer coil 12U. Similarly, the inner coil 11V and the outer coil 12V of the V phase are electrically connected in series or in parallel to each other via electrical wiring (not shown) or the like, and a voltage of the V phase is applied to the inner coil 11V and the outer coil 12V. Then, the inner coil 11W and the outer coil 12W of the W phase are electrically connected in series or in parallel to each other via electrical wiring (not shown) or the like, and a voltage of the W phase is applied to the inner coil 11W and the outer coil 12W.

[0021] In one example, a rotating magnetic field is generated by applying a voltage to the inner coil 11 and the outer coil 12 as described above. Then, an electromotive force is induced in the rotor 2 by the generated rotating magnetic field, and the rotor 2 is rotated by the induced electromotive force. Therefore, in the electric motor 1, any configuration may be adopted as long as the rotor 2 is rotated by utilizing the rotating magnetic field generated by applying a voltage to the inner coil 11 and the outer coil 12 of the stator 3.

[0022] FIG. 4 shows either the inner coil 11 or the outer coil 12. Note that each of the inner coil 11 and the outer coil 12 has the same configuration as that shown in FIG. 4. As shown in FIG. 4 and the like, each of the inner coil 11 and the outer coil 12 has a winding axis B, and in each of the inner coil 11 and the outer coil 12, the coil winding is wound around the winding axis B. In one example of FIGS. 1 to 3 and the like, the winding axis B of each of the inner coil 11 and the outer coil 12 extends along the radial direction of the electric motor 1. Further, in each of the inner coil 11 and the outer coil 12, the number of turns N indicating the number of circumferences of the coil winding about the axis of the winding axis B is defined.

[0023] Each of the inner coil 11 and the outer coil 12 includes a pair of coil side portions 15, 16 and a pair of bent portions 17, 18. In each of the inner coil 11 and the outer coil 12, the coil side portions 15, 16 are spaced apart from each other in the circumferential direction of the electric motor 1, and a space 20 is formed between the coil side portions 15, 16 in the circumferential direction of the electric motor 1. For this reason, in each of the inner coil 11 and the outer coil 12, the coil side portion (first coil side portion) 15 is located on the opposite side of the coil side portion (second coil side portion) 16 across the space 20. In each of the inner coil 11 and the outer coil 12, the winding axis B extends through the space 20. Further, in each of the inner coil 11 and the outer coil 12, the coil winding extends along the axial direction of the electric motor 1 at each of the coil side portions 15, 16.

[0024] In each of the inner coil 11 and the outer coil 12, the folded portions 17 and 18 are located apart from each other in the axial direction of the electric motor 1, and the aforementioned space 20 through which the winding shaft B passes is formed between the folded portions 17 and 18 in the axial direction of the electric motor 1. Therefore, in each of the inner coil 11 and the outer coil 12, the folded portion (first folded portion) 17 is located on the opposite side of the space 20 from the folded portion (second folded portion) 18. In each of the inner coil 11 and the outer coil 12, the coil winding is folded back at each of the folded portions 17 and 18. Due to the above configuration, each of the inner coil 11 and the outer coil 12 is formed in a ring shape or a substantially ring shape in which the space 20 is surrounded around the entire circumference of the winding shaft B by the portion composed of the coil sides 15 and 16 and the folded portions 17 and 18.

[0025] When three-phase inner coils 11U, 11V, and 11W are provided in the inner coil layer 7, the V-phase inner coil 11V is positioned adjacent to each U-phase inner coil 11U on one side in the circumferential direction of the motor 1. The W-phase inner coil 11W is positioned adjacent to each U-phase inner coil 11U on the opposite side of the circumferential direction of the motor 1 from the V-phase inner coil 11V. In the example shown in Figures 1 to 3, six inner coils 11 are provided. In the inner coil layer 7, the winding axis B of each inner coil 11 is positioned at an angle of 60° or approximately 60° relative to the winding axis B of adjacent inner coils 11 in the circumferential direction of the motor 1.

[0026] Furthermore, when three-phase outer coils 12U, 12V, and 12W are provided in the outer coil layer 8, the V-phase outer coil 12V is positioned adjacent to each U-phase outer coil 12U on one side in the circumferential direction of the motor 1. Then, the W-phase outer coil 12W is positioned adjacent to each U-phase outer coil 12U on the opposite side of the circumferential direction of the motor 1 from the V-phase outer coil 12V. In addition, in the example shown in Figures 1 to 3, six outer coils 12 are provided. In the outer coil layer 8, the winding axis B of each outer coil 12 is positioned at an angle of 60° or approximately 60° relative to the winding axis B of adjacent outer coils 12 in the circumferential direction of the motor 1.

[0027] Furthermore, in this embodiment, each of the outer coils 12 constituting the outer coil layer 8 is positioned at an angular position offset from any of the inner coils 11 constituting the inner coil layer 7 in the circumferential direction of the motor 1. In the motor 1, one corresponding winding axis B of the outer coil 12 is positioned at an angular position between the winding axes B of two adjacent inner coils 11 in the circumferential direction. In one example, the winding axes B of two adjacent inner coils 11 are positioned at an angular θ offset from each other in the circumferential direction of the motor 1. The winding axis B of each of the two adjacent inner coils 11 is positioned at an angular θ / 2 offset in the circumferential direction of the motor 1 with respect to the winding axis B of the outer coil 12 positioned between the winding axes B of those two inner coils 11. When six inner coils 11 and six outer coils 12 are provided, as in the example shown in Figures 1 to 3, the angle θ is 60° or approximately 60°, and the angle θ / 2 is 30° or approximately 30°.

[0028] Furthermore, the inner coil layer 7 is provided with three-phase inner coils 11U, 11V, and 11W, and the outer coil layer 8 is provided with three-phase outer coils 12U, 12V, and 12W. In this case, each of the U-phase outer coils 12U is positioned in the inner coil layer 7 between adjacent V-phase inner coils 11V and W-phase inner coils 11W in the circumferential direction of the motor 1. Each of the V-phase outer coils 12V is positioned in the inner coil layer 7 between adjacent W-phase inner coils 11W and U-phase inner coils 11U in the circumferential direction of the motor 1. And each of the W-phase outer coils 12W is positioned in the inner coil layer 7 between adjacent U-phase inner coils 11U and V-phase inner coils 11V in the circumferential direction of the motor 1.

[0029] Furthermore, for each of the inner coil 11 and the outer coil 12, the central position E1 of the coil side portion 15 in the circumferential direction of the motor 1 is defined, and the central position E2 of the coil side portion 16 in the circumferential direction of the motor 1 is defined. Then, for each of the inner coil 11 and the outer coil 12, the angle between the central position E1 of the coil side portion 15 and the central position E2 of the coil side portion 16 in the circumferential direction of the motor 1 is defined as the coil pitch α.

[0030] In each of the inner coils 11 and outer coils 12, the coil pitch α is greater than or equal to the angle αref obtained by dividing the angle corresponding to the entire circumference, 360°, by the total number of inner coils 11 and outer coils 12. In the example shown in Figures 1 to 3, the total number of inner coils 11 and outer coils 12 is 12, and the angle αref is 30°. Thus, the coil pitch α of each of the inner coils 11 and outer coils 12 is 30° or greater.

[0031] Furthermore, the coil pitch α mentioned above is defined as the individual coil pitch α1 of the inner coil 11 and the individual coil pitch α2 of the outer coil 12. In one example of this embodiment, the individual coil pitch α1 of the inner coil 11 is different from the individual coil pitch α2 of the outer coil 12. And, the individual coil pitch α1 of the inner coil 11 is larger than the individual coil pitch α2 of the outer coil 12.

[0032] In this example, as mentioned above, among the two types of coils, the inner coil 11 and the outer coil 12, the inner coil 11 is the first coil, positioned closer to the rotor 2, and the outer coil 12 is the second coil, positioned further away from the rotor 2. Therefore, each of the first coils, the inner coil 11, has a larger coil pitch α than each of the second coils, the outer coil 12. In one example, in a configuration where six inner coils 11 and six outer coils 12 are provided, the coil pitch α1 of each of the first coils, the inner coil 11, is 37.5°, and the coil pitch α2 of each of the second coils, the outer coil 12, is 32.5°.

[0033] In the inner coil layer 7, the coil pitches α1 of the multiple inner coils 11 may be the same or different from each other. In the outer coil layer 8, the coil pitches α2 of the multiple outer coils 12 may be the same or different from each other. However, in this example, even when the coil pitches α1 of the multiple inner coils 11 are different from each other, and when the coil pitches α2 of the multiple outer coils 12 are different from each other, the coil pitch α1 of each inner coil 11 is greater than the coil pitch α2 of each outer coil 12.

[0034] Furthermore, the number of turns N as described above is defined as the number of turns N1 for each inner coil 11 and the number of turns N2 for each outer coil 12. In one example of this embodiment, the number of turns N1 for each inner coil 11 is different from the number of turns N2 for each outer coil 12. And the number of turns N1 for each inner coil 11 is greater than the number of turns N2 for each outer coil 12.

[0035] As described above, in this example, each of the inner coils 11, which are the first coils located closer to the rotor 2, has more turns N than each of the outer coils 12, which are the second coils located further away from the rotor 2. In one example, in a configuration where six inner coils 11 and six outer coils 12 are provided, each of the inner coils 11, which are the first coils, has 6.5 turns N1, and each of the outer coils 12, which are the second coils, has 6 turns N2.

[0036] In the inner coil layer 7, the number of turns N1 of the multiple inner coils 11 may be the same or different from each other. In the outer coil layer 8, the number of turns N2 of the multiple outer coils 12 may be the same or different from each other. However, in this example, even when the number of turns N1 of the multiple inner coils 11 are different from each other, and when the number of turns N2 of the multiple outer coils 12 are different from each other, the number of turns N1 of each inner coil 11 is greater than the number of turns N2 of each outer coil 12.

[0037] As described above, in this embodiment, in the stator 3, an outer coil layer 8 is provided on the outer circumference of the inner coil layer 7, forming two coil layers. In the inner coil layer 7, a plurality of coreless inner coils 11 are arranged in a circumferential direction, and in the outer coil layer 8, a plurality of coreless outer coils 12 are arranged in a circumferential direction without contacting the inner coils 11. This configuration makes it possible to increase the area occupied by the inner coils 11 and outer coils 12 in the stator 3.

[0038] Furthermore, in this embodiment, the coil pitch α of the inner coil 11 and the outer coil 12 is greater than or equal to the angle αref obtained by dividing 360° by the total number of inner coils 11 and outer coils 12. As a result, the angular range occupied by the inner coil 11 and the outer coil 12 in the circumferential direction of the motor 1 increases, and the area occupied by the inner coil 11 and the outer coil 12 in the stator 3 increases further. By increasing the area occupied by the inner coil 11 and the outer coil 12, it becomes possible to increase the amount of linked magnetic flux that links with the inner coil 11 and the outer coil 12 in the rotating magnetic field generated by applying voltage to the inner coil 11 and the outer coil 12 of the stator 3. In the motor 1, the increase in the amount of linked magnetic flux with the inner coil 11 and the outer coil 12 increases the torque that rotates the rotor 2, and the torque characteristics of the motor 1 are improved.

[0039] Furthermore, in this embodiment, the outer coil 12 is superimposed on the outer circumference of the inner coil 11 without forming any radially bent portions on the inner coil 11 or the outer coil 12 of the motor 1. Therefore, by arranging each of the outer coils 12 with a gap between them and the inner coil 11, even if two layers of coils are formed on the stator 3, contact between the inner coil 11 and the outer coil 12 with other coils is effectively prevented. Consequently, in a configuration in which multiple phases of power, such as three-phase power, are supplied to the stator 3, contact between coils of different phases is effectively prevented, and electrical insulation between coils of different phases is appropriately ensured.

[0040] Furthermore, in one example of this embodiment, the coil pitch α is larger for each of the inner coils 11, which are the first coils located closer to the rotor 2, compared to each of the outer coils 12, which are the second coils located further away from the rotor 2. In a configuration where the rotor 2 is located on the inner circumference side relative to the stator 3, increasing the coil pitch α1 of each of the inner coils 11, which are the first coils located closer to the rotor 2, increases the amount of flux linkage with the coils (inner coils 11) at a position close to the rotor 2 in the generated rotating magnetic field. As a result, the torque that rotates the rotor 2 is further increased, and the torque characteristics of the electric motor 1 are further improved.

[0041] Furthermore, in one example of this embodiment, each of the inner coils 11, which are the first coils located closer to the rotor 2, has more turns N than each of the outer coils 12, which are the second coils located further away from the rotor 2. In a configuration where the rotor 2 is located on the inner circumference side relative to the stator 3, increasing the number of turns N1 of each of the inner coils 11, which are the first coils located closer to the rotor 2, makes it possible to appropriately increase the coil pitch α1 of each of the inner coils 11.

[0042] (modified version) In the embodiments described above, the rotor 2 is positioned on the inner circumference side of the stator 3. However, in one modified example, the rotor 2 is positioned on the outer circumference side of the stator 3 in the electric motor 1. In this case as well, the stator 3 includes an inner coil layer 7 and an outer coil layer 8, similar to the embodiments described above. The coil pitch α of each of the multiple inner coils 11 in the inner coil layer 7 and the multiple outer coils 12 in the outer coil layer 8 is greater than or equal to the angle αref obtained by dividing 360° by the total number of inner coils 11 and outer coils 12. As a result, in this modified example as well, the area occupied by the inner coils 11 and outer coils 12 in the stator 3 is increased, making it possible to increase the amount of linked magnetic flux that links with the inner coils 11 and outer coils 12 in the generated rotating magnetic field.

[0043] However, in this modified example, the outer coil 12 is the first coil, positioned closer to the rotor 2, among the two types of coils, the inner coil 11 and the outer coil 12. The inner coil 11 is the second coil, positioned further away from the rotor 2.

[0044] Therefore, in this modified example, it is preferable that the coil pitch α of each of the outer coils 12, which are the first coils located closer to the rotor 2, is larger than that of each of the inner coils 11, which are the second coils located further away from the rotor 2. In a configuration where the rotor 2 is located on the outer circumference relative to the stator 3, increasing the coil pitch α2 of each of the outer coils 12, which are the first coils located closer to the rotor 2, increases the amount of magnetic flux linkage with the coils (outer coils 12) at a position close to the rotor 2 in the generated rotating magnetic field. As a result, the torque that rotates the rotor 2 is further increased, and the torque characteristics of the electric motor 1 are further improved.

[0045] Furthermore, in this modified configuration, it is preferable that each of the outer coils 12, which are the first coils located closer to the rotor 2, has a greater number of turns N than each of the inner coils 11, which are the second coils located further away from the rotor 2. In a configuration where the rotor 2 is located on the outer circumference relative to the stator 3, increasing the number of turns N2 of each of the outer coils 12, which are the first coils located closer to the rotor 2, makes it possible to appropriately increase the coil pitch α2 of each of the outer coils 12.

[0046] Furthermore, the stator structure of the stator 3 in the electric motor 1 of the above-described embodiment can also be applied as the stator structure of a generator. In a generator, a rotating magnetic field is generated by the rotation of the rotor. The rotating magnetic field generated by the rotation of the rotor induces a voltage (electromotive force) in the inner coil 11 and outer coil 12, which make up the coils of the stator.

[0047] In the generator's stator structure, the stator 3 comprises an inner coil layer 7 and an outer coil layer 8. The coil pitch α of each of the multiple inner coils 11 in the inner coil layer 7 and the multiple outer coils 12 in the outer coil layer 8 is greater than or equal to the angle αref obtained by dividing 360° by the total number of inner coils 11 and outer coils 12. This increases the area occupied by the inner coils 11 and outer coils 12 in the stator 3, making it possible to increase the amount of flux linkage with the inner coils 11 and outer coils 12 in the rotating magnetic field generated by the rotation of the rotor 2. In the generator, the increased amount of flux linkage with the inner coils 11 and outer coils 12 appropriately increases the voltage induced in the inner coils 11 and outer coils 12 (the coils of the stator 3).

[0048] Furthermore, in the stator structure of the generator, it is preferable that the coil pitch α is larger for each of the first coils, which are located closer to the rotor 2 among the inner coil 11 and the outer coil 12, compared to each of the second coils, which are located further away from the rotor 2 among the inner coil 11 and the outer coil 12. It is also preferable that the number of turns N is larger for each of the first coils compared to each of the second coils. In the stator structure of the generator, increasing the coil pitch of each of the first coils located closer to the rotor 2 increases the amount of flux linkage with the coils at positions close to the rotor 2 in the generated rotating magnetic field. As a result, the voltage induced in the coils of the stator 3 increases further.

[0049] According to at least one embodiment or example, in the inner coil layer, a plurality of coreless inner coils are arranged in a circumferential direction, and in the outer coil layer, a plurality of coreless outer coils are arranged in a circumferential direction on the outer circumference of the inner coil layer without contacting the inner coils. The coil pitch of the inner coils and outer coils is greater than or equal to the angle obtained by dividing 360° by the total number of inner and outer coils. This makes it possible to provide a stator structure for a rotating electric machine that can increase the amount of linked magnetic flux that links with the coreless coils in the generated rotating magnetic field.

[0050] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. The following are additional notes. [1] A stator structure in a rotating electric machine, An inner coil layer comprising multiple coreless inner coils, wherein the inner coils are arranged in a circumferential direction, An outer coil layer comprising a coreless plurality of outer coils, wherein the outer coils are arranged in the circumferential direction on the outer circumference side of the inner coil layer without contacting the inner coils, It is equipped with, The rotor is rotated by utilizing the rotating magnetic field generated by applying voltage to the inner coil and the outer coil, or by inducing a voltage in the inner coil and the outer coil by the rotating magnetic field generated by the rotation of the rotor. The coil pitch of the inner coil and the outer coil is greater than or equal to the angle obtained by dividing 360° by the total number of inner and outer coils. Stator structure. [2] The stator structure of [1] wherein the coil pitch of each of the outer coils is different from the coil pitch of each of the inner coils. [3] The stator structure of [2] wherein the coil pitch is larger in each of the inner coil and the first coil which is located on the side closer to the rotor among the outer coils. [4] A stator structure in which the number of turns of each of the outer coils is different from the number of turns of each of the inner coils, any one of [1] to [3]. [5] The stator structure of [4] wherein each of the inner coil and the first coil, which is located on the side closer to the rotor among the outer coils, has more turns than each of the second coil, which is located on the side further from the rotor among the inner coil and the outer coils. [Explanation of Symbols]

[0051] 1...Electric motor, 2...Rotor, 3...Stator, 7...Inner coil layer, 8...Outer coil layer, 11(11U,11V,11W)...Inner coil, 12(12U,12V,12W)...Outer coil, P...Rotation axis, B...Winding axis, α(α1,α2)...Coil pitch, αref...Angle, N(N1,N2)...Number of turns.

Claims

1. A stator structure in a rotating electric machine, An inner coil layer comprising multiple coreless inner coils, wherein the inner coils are arranged in a circumferential direction, An outer coil layer comprising a coreless plurality of outer coils, wherein the outer coils are arranged in the circumferential direction on the outer circumference side of the inner coil layer without contacting the inner coils, It is equipped with, The rotor is rotated by utilizing the rotating magnetic field generated by applying voltage to the inner coil and the outer coil, or by inducing a voltage in the inner coil and the outer coil by the rotating magnetic field generated by the rotation of the rotor. The coil pitch of each of the inner coil and the outer coil is greater than or equal to the angle obtained by dividing 360° by the total number of inner and outer coils. The coil pitch of each of the outer coils is different from the coil pitch of each of the inner coils. In each of the first coils, which is positioned closer to the rotor than the inner coil and the outer coil, the coil pitch is larger than that of each of the second coils, which is positioned further away from the rotor than the inner coil and the outer coil. Stator structure.

2. The stator structure according to claim 1, wherein the number of turns of each of the outer coils is different from the number of turns of each of the inner coils.

3. The stator structure of claim 2, wherein each of the first coils has more turns than each of the second coils.

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