Rotating Electric Machine

Abstract

To provide a rotary electric machine capable of preventing a rise in costs, and of preventing an eddy current from being generated and preventing a torque ripple from being generated.SOLUTION: According to a stator 10 of a rotary electric machine 1, a teeth part 12 comprises a teeth body part 16 around which a coil 14 is wound; and a flange part 17 around which no coil 14 is wound, that is made from a magnetic material and that extends in a circumferential direction and inside a radial direction of the teeth body part 16 from an end inside the radial direction. The flange part 17 comprises a flange base part 18 extending inside the radial direction of the teeth part 16 from the end inside the radial direction, and a flange extension part 19 extending in a circumferential direction from the flange base part 18. The flange extension part 19 comprises a first flange extension part 19A arranged inside the radial direction, and a second flange extension part 19B arranged outside the radial direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] In a conventional rotating electric machine, a technique is known in which a substantially annular pressing member is provided on the tip side of the teeth of a stator core, and the pressing member presses the coil against a yoke portion (see Patent Document 1). In the rotating electric machine described in Patent Document 1, the pressing member has an annular non-magnetic body arranged on the tip side, and an annular magnetic body arranged between the non-magnetic body and the coil, and the non-magnetic body and the magnetic body form a flux barrier.

[0003] According to the rotating electric machine described in Patent Document 1, the magnetic flux from the rotor is attracted to the magnetic body of the pressing member, so that the magnetic flux enters the teeth without interlinking with the coil. In addition, because the non-magnetic body is disposed on the tip side of the teeth, the magnetic body can be disposed back from the tip of the teeth. As a result, the rotating electric machine described in Patent Document 1 can suppress saturation due to the magnetic flux density of the magnetic body and reduce eddy current loss. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-130556 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the rotating electric machine described in Patent Document 1, adding the pressing member to the teeth increases the number of parts and assembly steps, which may increase costs. Also, because the pressing member has a non-magnetic body located closer to the outer circumferential surface of the rotor than the magnetic body, the amount of magnetic flux passing through the pressing member is smaller than the amount of magnetic flux flowing through the teeth, which increases the amount of torque fluctuation between the pressing member and the teeth when the rotor rotates, which may make torque ripples more likely to occur.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a rotating electric machine capable of suppressing increases in cost, the occurrence of eddy currents, and the occurrence of torque ripples. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a rotating electric machine comprising a stator having a stator core made of a magnetic material and provided with a coil, and a rotor having a rotor core in which a plurality of permanent magnets are embedded, the stator core having an annular yoke portion and teeth portions protruding radially inward from an inner circumferential surface of the yoke portion, the teeth portions having a teeth main body portion around which the coil is wound, and a flange portion made of a magnetic material, extending radially inward and circumferentially from a radially inner end portion of the teeth main body portion, and around which the coil is not wound, the flange portion having a flange base portion extending radially inward from a radially inner end portion of the teeth main body portion, and a flange extension portion extending circumferentially from the flange base portion, the flange extension portion having a first flange extension portion arranged radially inward and a second flange extension portion arranged radially outward. a connection surface that radially connects the first flange extension portion and the second flange extension portion; Have The connection surface is formed as a concave curved surface that is concave in the circumferential direction, and the first flange extension portion extends in the circumferential direction further than the second flange extension portion. It is characterized by the fact that Effect of the Invention

[0008] According to the present invention, it is possible to provide a rotating electric machine capable of suppressing increases in cost, the occurrence of eddy currents, and the occurrence of torque ripples. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a rotating electric machine according to an embodiment of the present invention, taken along a plane perpendicular to the rotating shaft. [Diagram 2] FIG. 2 is a cross-sectional view of a portion of a stator of a rotating electric machine according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing a magnetic flux distribution at the time of maximum load in a rotating electric machine according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the correlation between the torque ripple rate and the dimensional ratio of the flange portion of the rotary electric machine according to one embodiment of the present invention. [Diagram 5] 5(A) to 5(D) are diagrams showing the magnetic flux distribution in the flange portion at points (A) to (D) in FIG. 4, respectively. [Figure 6] FIG. 6 is a diagram showing a magnetic flux distribution in the flange of the rotating electric machine according to one embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing a magnetic flux distribution in a flange portion of a rotating electric machine according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A rotating electric machine according to an embodiment of the present invention includes a stator having a stator core made of a magnetic material and provided with a coil, and a rotor having a rotor core in which a plurality of permanent magnets are embedded, the stator core having an annular yoke portion and teeth portions protruding radially inward from an inner peripheral surface of the yoke portion, the teeth portions having a teeth main body portion around which a coil is wound, and a flange portion made of a magnetic material, extending radially inward and circumferentially from a radially inner end of the teeth main body portion, and around which the coil is not wound, the flange portion having a flange base portion extending radially inward from a radially inner end of the teeth main body portion, and a flange extension portion extending circumferentially from the flange base portion, the flange extension portion having a first flange extension portion disposed radially inward and a second flange extension portion disposed radially outward. This makes it possible for the rotating electric machine according to the embodiment of the present invention to suppress increases in cost, generation of eddy currents, and generation of torque ripples. EXAMPLES

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotating electrical machine according to the present invention will now be described with reference to the drawings.

[0012] 1, a rotating electric machine 1 according to this embodiment is an interior permanent magnet synchronous motor (hereinafter referred to as IPMSM) in which permanent magnets are embedded inside a rotor. The rotating electric machine 1 has performance suitable for being mounted as a drive source in, for example, a hybrid vehicle or an electric vehicle.

[0013] The rotating electric machine 1 includes a stator 10 formed in an annular shape and a rotor 20 rotatably housed within the stator 10. The rotor 20 is fixed to a rotating shaft 2 that rotates about an axis O, and rotates integrally with the rotating shaft 2. A housing (not shown) is provided on the outer circumferential surface 11A side of the stator 10, and the rotating electric machine 1 is housed in this housing. A gap is provided between an inner circumferential surface 11B of the stator 10 and an outer circumferential surface 21A of the rotor 20.

[0014] The stator 10 is fixed to a motor case (not shown). The stator 10 includes an annular stator core 11. The stator core 11 is formed by laminating electromagnetic steel sheets made of a magnetic material with high magnetic permeability in the axial direction along the axis of the rotating shaft 2.

[0015] Stator core 11 has an annular yoke portion 15 and a plurality of teeth portions 12 protruding radially inward from the inner peripheral surface of yoke portion 15. A plurality of teeth portions 12 are provided along the circumferential direction. A plurality of slots 13, which are groove-shaped spaces, are formed between adjacent teeth portions 12 in the circumferential direction.

[0016] The radial direction refers to a direction perpendicular to the axial direction. The radial inner side refers to a side closer to the rotating shaft 2 in the radial direction, and the radial outer side refers to a side farther from the rotating shaft 2 in the radial direction. The circumferential direction refers to a circumferential direction centered on the rotating shaft 2.

[0017] Three-phase coils 14, i.e., W-phase, V-phase, and U-phase, are arranged in each slot 13 of the stator core 11 along the circumferential direction of the stator core 11. The W-phase, V-phase, and U-phase coils 14 are each distributed around the corresponding tooth portion 12.

[0018] The stator 10 generates a rotating magnetic field that rotates in the circumferential direction when a three-phase AC current is supplied to the coils 14. The magnetic flux generated by the stator 10 is configured to interlink with the rotor 20. This allows the stator 10 to rotate the rotor 20.

[0019] The rotor 20 includes an annular rotor core 21, a plurality of permanent magnet pairs 23, and a magnetic pole portion 24.

[0020] Rotor core 21 is made by laminating electromagnetic steel sheets, which are magnetic materials with high magnetic permeability, in the axial direction along the axis of rotating shaft 2. A plurality of slit pairs 22 are formed in rotor core 21 along the circumferential direction of rotor 20. An inner peripheral surface 21B of rotor core 21 is fixed to rotating shaft 2.

[0021] The slit pair 22 is made up of a pair of slits 22A and 22B. The pair of slits 22A and 22B are provided so as to form a V shape that widens from the radially inner side toward the radially outer side, i.e., the stator side.

[0022] Permanent magnets 23A, 23B are fitted into the pair of slits 22A, 22B. The pair of permanent magnets 23A, 23B are arranged in a V-shape expanding from the radially inner side toward the radially outer side, i.e., the stator side, to constitute a permanent magnet pair 23.

[0023] The permanent magnets 23A and 23B are arranged so that the same polarity faces face each other. As a result, a magnetic pole portion 24 having the same polarity as the opposing polarity faces is formed between the permanent magnets 23A and 23B. In this way, the magnetic pole portion 24 is formed as an N magnetic pole or an S magnetic pole depending on the polarity of the permanent magnets 23A and 23B arranged in a V-shape.

[0024] The pair of permanent magnets 23A, 23B are arranged such that the polar faces of the circumferentially adjacent permanent magnet pairs 23 face in opposite directions. As a result, the polarities of the magnetic pole portions 24 adjacent to each other in the circumferential direction are opposite, i.e., the magnetic pole portions 24 are opposite polarity. Therefore, in the rotor 20, the magnetic pole portions 24 of the N pole (indicated as "N" in FIG. 1) and the magnetic pole portions 24 of the S pole (indicated as "S" in FIG. 1) are alternately formed in the circumferential direction.

[0025] In this manner, the rotor 20 has an inverse salient pole structure in which a plurality of permanent magnet pairs 23 are provided, each of which has a pair of permanent magnets 23A, 23B arranged in a V-shape.

[0026] Because the rotor 20 of the rotating electric machine 1 has this type of inverted salient pole structure, the inductance in the axial direction passing between a pair of permanent magnets 23A, 23B (hereinafter referred to as the d-axis direction) is smaller than the inductance in the axial direction passing between circumferentially adjacent pairs of permanent magnets 23 and electrically and magnetically perpendicular to the d-axis (hereinafter referred to as the q-axis direction).

[0027] Therefore, in the inverse salient pole structure, in addition to the magnet torque generated by the permanent magnet pair 23, a reluctance torque corresponding to the difference between the inductance in the d-axis direction and the inductance in the q-axis direction can be generated, thereby improving the torque density in the rotating electric machine 1.

[0028] Furthermore, a first flux barrier 25A and a second flux barrier 25B are formed adjacent to the pair of permanent magnets 23A, 23B in the rotor core 21. The first flux barrier 25A and the second flux barrier 25B are gaps for restricting intrusion of magnetic flux.

[0029] The first flux barrier 25A is formed adjacent to the outer peripheral ends of the pair of permanent magnets 23A, 23B, respectively. The second flux barrier 25B is formed between the pair of permanent magnets 23A, 23B, adjacent to the inner peripheral ends of these permanent magnets 23A, 23B.

[0030] Before the permanent magnets 23A, 23B are fitted into the rotor core 21, the slits 22A, 22B corresponding to the permanent magnets 23A, 23B, respectively, and the first flux barrier 25A and second flux barrier 25B form a continuous, integrated space.

[0031] 2, in this embodiment, the teeth 12 have a teeth main body 16 around which the coil 14 is wound, and a flange 17 around which the coil 14 is not wound. The flange 17 is made of a magnetic material, and extends radially inward and circumferentially from the radially inner end of the teeth main body 16. Thus, in this embodiment, the flange 17 is formed as a part of the teeth 12 of the stator core 11 made of a magnetic material.

[0032] The flange portion 17 has a flange base portion 18 extending radially inward from a radially inner end portion of the tooth main body portion 16, and a flange extension portion 19 extending circumferentially from the flange base portion 18. The flange extension portion 19 has a first flange extension portion 19A disposed radially inward and a second flange extension portion 19B disposed radially outward.

[0033] First flange extension 19A extends in the circumferential direction, thereby ensuring an area facing rotor 20 and suppressing magnetic flux from entering slot 13 in which coil 14 is disposed. Second flange extension 19B extends in the circumferential direction, thereby positioning coil 14 at a position radially outwardly away from outer circumferential surface 21A of rotor 20.

[0034] In addition, in Fig. 2, the boundary between the tooth main body portion 16 and the flange portion 17 in the tooth portion 12 is represented by a dashed line. Also, the boundary between the flange base portion 18 and the flange extension portion 19 in the flange portion 17 is represented by a dashed line. These dashed lines are virtual lines for clarifying the boundary positions of the respective parts of the tooth portion 12.

[0035] The flange extension portion 19 has a connection surface 19C that radially connects the first flange extension portion 19A and the second flange extension portion 19B. The connection surface 19C is formed as a concave curved surface that is recessed in the circumferential direction. Therefore, the base of the first flange extension portion 19A and the base of the second flange extension portion 19B are smoothly continuous so as to describe an arc by the connection surface 19C formed of a concave curved surface.

[0036] The first flange extension portion 19A extends more in the circumferential direction than the second flange extension portion 19B. For this reason, the distance between the first flange extension portions 19A adjacent to each other in the circumferential direction is smaller than the distance between the second flange extension portions 19B adjacent to each other in the circumferential direction.

[0037] Here, when the distance between the first flange extension portions 19A adjacent to each other in the circumferential direction is L1 and the distance between the second flange extension portions 19B adjacent to each other in the circumferential direction is L2, it is preferably configured such that 2.9 < L2 / L1 < 6.2 holds.

[0038] Also, when the distance between the radially inner ends of the tooth main body portions 16 adjacent to each other in the circumferential direction is L3, it is preferably configured such that 9.6 < L3 / L1 < 24 holds.

[0039] As described above, in the rotating electrical machine 1 according to this embodiment, the tooth portion 12 has a tooth main body portion 16 around which the coil 14 is wound, and a flange portion 17 made of a magnetic material that extends radially inward and circumferentially from the radially inner end of the tooth main body portion 16 and around which the coil 14 is not wound. Further, the flange portion 17 has a flange base portion 18 that extends radially inward from the radially inner end of the tooth main body portion 16, and a flange extension portion 19 that extends circumferentially from the flange base portion 18. And the flange extension portion 19 has a first flange extension portion 19A arranged radially inward and a second flange extension portion 19B arranged radially outward.

[0040] Generally, high-frequency magnetic flux generated during rotation of the rotor 20 is distributed mostly between the outer peripheral surface 21A of the rotor 20 and the vicinity of the inner peripheral surface 11B of the stator 10. Therefore, if high-frequency magnetic flux is linked to the coil 14 close to the outer peripheral surface 21A of the rotor 20, eddy currents are generated in the coil 14. In this embodiment, the coil 14 is not wound around the flange portion 17 near the inner peripheral surface 11B of the stator 10, and the second flange extension portion 19B is provided on the flange portion 17, so that the coil 14 can be positioned at a position radially outwardly away from the outer peripheral surface 21A of the rotor 20. Therefore, without using a separate member such as a pressing member as in the conventional technology, as shown in FIG. 3, it is possible to suppress the high-frequency magnetic flux from being linked to the coil 14 near the inner peripheral surface 11B of the stator 10, and suppress the generation of eddy currents.

[0041] Furthermore, because flange portion 17 is made of a magnetic material, flange portion 17 can be formed as a part of teeth portion 12 without being manufactured separately, which makes it possible to suppress increases in costs.

[0042] In addition, since the first flange extension portion 19A of the flange portion 17 is made of a magnetic material, the area where magnetic flux intersects between the outer peripheral surface 21A of the rotor 20 and the inner peripheral surface 11B of the stator 10 can be made larger, thereby suppressing the occurrence of torque ripple compared to conventional technology.

[0043] As a result, increases in costs and the occurrence of eddy currents and torque ripples can be suppressed.

[0044] Furthermore, in the rotating electric machine 1 according to this embodiment, the flange extension portion 19 has a connection surface 19C that radially connects the first flange extension portion 19A and the second flange extension portion 19B, and the connection surface 19C is formed into a concave curved surface that is recessed in the circumferential direction.

[0045] This allows the surface of first flange extension 19A and the surface of second flange extension 19B to be smoothly connected by connecting surface 19C, which is a concave curved surface. Therefore, as shown in Fig. 3, it is possible to prevent the spacing between the magnetic flux lines passing through flange extension 19 from narrowing, so that it is possible to suppress a decrease in magnetic flux density due to magnetic saturation, and to suppress the occurrence of torque ripple.

[0046] 6, in this embodiment, the magnetic flux lines F11 and F12 running in the circumferential direction on the first flange extension portion 19A of the teeth portion 12 can smoothly change direction radially outward along the connection surface 19C consisting of a concave curved surface. Therefore, the distance D1 between the magnetic flux lines F11 and F12 can be increased, and the occurrence of magnetic saturation can be suppressed.

[0047] 7 has a connection surface 19D that extends linearly in the radial direction, and this connection surface 19D connects the first flange extension portion 19A and the second flange extension portion 19B. Therefore, the connection surface 19D is perpendicular to the first flange extension portion 19A and the second flange extension portion 19B, and does not smoothly connect the base portions of the first flange extension portion 19A and the second flange extension portion 19B. Therefore, in the rotating electric machine 1A of the comparative example, the magnetic flux lines F21 and F22 running circumferentially through the first flange extension portion 19A of the tooth portion 12 bend when they change direction radially outward along the connection surface 19D, and the distance D2 between the magnetic flux lines F21 and F22 becomes small, so that the effect of suppressing magnetic saturation is not optimal.

[0048] In the rotating electric machine 1 according to this embodiment, the first flange extension portion 19A extends further in the circumferential direction than the second flange extension portion 19B.

[0049] Thus, since the first flange extension portion 19A closer to the outer peripheral surface 21A of the rotor 20 is longer in the circumferential direction than the second flange extension portion 19B, the amount of magnetic flux intersecting at a position closer to the outer peripheral surface 21A of the rotor 20 can be increased, and the motor torque can be increased as compared with the case where the magnetic flux extending from the second flange extension portion 19B intersects the outer peripheral surface 21A of the rotor 20.

[0050] Further, in the rotating electrical machine 1 according to the present embodiment, when the distance between the adjacent first flange extension portions 19A in the circumferential direction is L1 and the distance between the adjacent second flange extension portions 19B in the circumferential direction is L2, it is preferably configured such that 2.9 < L2 / L1 < 6.2 holds.

[0051] By doing so, the torque ripple ratio can be suppressed to the minimum value. The torque ripple ratio is the occurrence rate of torque ripple.

[0052] Here, FIGS. 4(A), (B), (C), and (D) are diagrams showing the correlation between the torque ripple ratio and the dimensional ratio (L2 / L1) of the flange portion 17. The vertical axis of FIG. 4 indicates the torque ripple ratio, and the value increases as going upward. Further, the horizontal axis indicates L2 / L1, and the value increases as going rightward.

[0053] In FIG. 4, point (B) is the torque ripple ratio when L2 / L1 is 2.9, and point (C) is the torque ripple ratio when L2 / L1 is 6.2. Further, point (A) is the torque ripple ratio when L2 / L1 is smaller than 2.9, and point (D) is the torque ripple ratio when L2 / L1 is larger than 6.2.

[0054] As can be seen from FIG. 4, between point (B) and point (C), the torque ripple ratio is substantially constant at the minimum value (not shown in FIG. 4 but about 1%). Further, the torque ripple ratio increases as L2 / L1 becomes smaller than point (B), and the torque ripple ratio increases as L2 / L1 becomes larger than point (D).

[0055] Figs. 5(A), (B), (C), and (D) show the magnetic flux distributions of the rotating electrical machine 1 at points (A), (B), (C), and (D) in Fig. 4, respectively. In Figs. 5(B) and (C), since the distance L1 (see Fig. 2) between the adjacent first flange extending portions 19A in the circumferential direction can be made sufficiently narrow, the change in the magnetic flux density of the first flange extending portion 19A during the rotation of the rotor 20 can be reduced, and the generation of torque ripple can be most effectively suppressed.

[0056] Also, in Figs. 5(B) and (C), since the curvature of the connecting surface 19C (see Fig. 2) can be made sufficiently small to form a gently curved connecting surface 19C, the interval of the magnetic flux from the first flange extending portion 19A to the tooth main body portion 16 (see Fig. 2) becomes small, and the magnetic flux density at the flange portion 17 can be decreased. Therefore, the occurrence of magnetic saturation can be most effectively suppressed, and thus the occurrence of torque ripple can be most effectively suppressed.

[0057] Here, as L3 / L1 increases, the circumferential width of the inner peripheral side end portion of the tooth main body portion 16 increases. For this reason, the area where the outer peripheral surface 21A of the rotor 20 and the inner peripheral surface of the tooth main body portion 16 face each other increases, and when this facing area increases, the rapid change in the amount of magnetic flux when the magnetic flux changes decreases. Therefore, the larger L3 / L1 is, the more suitably the generation of torque ripple can be suppressed.

[0058] On the other hand, when L3 / L1 is too large, the interval between the magnetic flux lines in the flange extending portion 19 becomes small, and magnetic flux short - circuit is likely to occur between the second flange extending portion 19B and the first flange extending portion 19A. Therefore, magnetic saturation at the first flange extending portion 19A due to the occurrence of the short - circuit increases, and it is conceivable that torque ripple increases due to the increase in magnetic saturation.

[0059] Therefore, in the rotating electrical machine 1 according to this embodiment, when the distance between the radially inner - side end portions of the adjacent tooth main body portions 16 in the circumferential direction is L3, it is preferably configured such that 9.6 < L3 / L1 < 24 holds.

[0060] As a result, it is possible to suppress a short circuit of magnetic flux between the second flange extending portion 19B and the first flange extending portion 19A, and it is possible to suppress the occurrence of torque ripple.

[0061] Both FIGS. 5(B) and 5(C) are configured such that 9.6 < L3 / L1 < 24 holds. FIGS. 5(B) and 5(C) can most suppress the short circuit of magnetic flux from the second flange extending portion 19B to the first flange extending portion 19A, and can most suppress the occurrence of torque ripple.

[0062] Note that the rotating electrical machine 1 can be suitably used not only as a drive source for a hybrid vehicle or an electric vehicle, but also as a drive source for, for example, wind power generation or a machine tool.

[0063] Although embodiments of the present invention have been disclosed, it is obvious that those skilled in the art can make changes without departing from the scope of the present invention. It is intended that all such modifications and equivalents be included in the following claims.

Explanation of Reference Numerals

[0064] 1... Rotating electrical machine, 10... Stator, 11... Stator core, 12... Tooth portion, 14... Coil, 15... Yoke portion, 16... Tooth main body portion, 17... Flange portion, 18... Flange base portion, 19... Flange extending portion, 19A... First flange extending portion, 19B... Second flange extending portion, 19C... Connection surface, 20... Rotor, 21... Rotor core, 23A, 23B... Permanent magnet, L1... Distance (distance between the first flange extending portions adjacent in the circumferential direction), L2... Distance (distance between the second flange extending portions adjacent in the circumferential direction), L3... Distance (distance between the radially inner ends of the tooth main body portions adjacent in the circumferential direction)

Claims

1. a stator having a stator core made of a magnetic material and provided with a coil; A rotor having a rotor core in which a plurality of permanent magnets are embedded, The stator core is An annular yoke portion; a teeth portion protruding radially inward from an inner circumferential surface of the yoke portion, The teeth portion includes: a teeth main body portion around which the coil is wound; a flange portion made of a magnetic material, extending radially inward and circumferentially from a radially inner end of the tooth body portion, and around which the coil is not wound, The flange portion is a flange base portion extending radially inward from a radially inner end portion of the tooth main body portion; A flange extension portion extending in a circumferential direction from the flange base portion, The flange extension portion has a first flange extension portion disposed radially inward, a second flange extension portion disposed radially outward, and a connection surface that radially connects the first flange extension portion and the second flange extension portion, The connection surface is formed into a concave curved surface that is concave in the circumferential direction, The rotating electric machine according to claim 1, wherein the first flange extension portion extends further in a circumferential direction than the second flange extension portion.

2. A rotating electric motor as described in claim 1, characterized in that when the distance between adjacent first flange extension portions in the circumferential direction is L1 and the distance between adjacent second flange extension portions in the circumferential direction is L2, 2.9 < L2 / L1 < 6.2 holds.

3. A rotating electric motor as described in claim 2, characterized in that when the distance between the radially inner ends of the circumferentially adjacent teeth main body portions is L3, 9.6 < L3 / L1 < 24 holds.

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