Motor

Abstract

To provide a motor that can ensure large detent torque.SOLUTION: A motor 10 includes: a ring-shaped stator 12 with a plurality of teeth 16 extending in the circumferential direction toward an axial center L, and windings 18 wound around the teeth; and a rotor 13 including a rotor core 22 rotatably accommodated inside the stator, and a plurality of permanent magnets 23 arranged in the circumferential direction inside the rotor core, and having a plurality of magnetic pole portions 22b formed in the circumferential direction by the plurality of permanent magnets on the surface of the rotor core facing the stator. The magnetic pole portion includes a groove 22c recessed on a radial inside, and the groove is formed circumferentially symmetrically from the magnetic pole center which is the circumferential center of the magnetic pole portion. The angle of the groove width at the radial outer end of the groove of Wg and the number of magnetic pole portions of P are set to satisfy 0.12<Wg / (360 / P)<0.31.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a motor. [Background technology]

[0002] Motors used in devices that require a position-maintaining function, such as electric variable valve timing devices, require a large detent torque. As a motor that aims to improve the detent torque, a motor with grooves provided on the surface of the rotor that faces the stator has been proposed (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-41530 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the motor described above, the grooves provided in the rotor can improve the detent torque, but the inventors of the present invention have been studying a configuration that can also accommodate cases where a larger detent torque is required.

[0005] An object of the present invention is to provide a motor capable of ensuring a large detent torque. [Means for solving the problem]

[0006] The motor (10) for solving the above problems includes an annular stator (12) having a plurality of teeth (16) extending in the circumferential direction toward the axis center (L) and windings (18) wound around the teeth, a rotor core (22) rotatably accommodated inside the stator, and a plurality of permanent magnets (23, 32, 33, 36, 37) provided inside the rotor core in the circumferential direction. The rotor (13) is provided with a plurality of magnetic pole portions (22b) formed in the circumferential direction by the plurality of permanent magnets on the opposing surface of the rotor core with respect to the stator. The magnetic pole portions have grooves (22c, 31) recessed inward in the radial direction, and the grooves are symmetrically formed in the circumferential direction from the magnetic pole center which is the circumferential center of the magnetic pole portion. The angle of the groove width at the radially outer end of the groove is defined as Wg, and the number of the magnetic pole portions is defined as P, and it is set to satisfy 0.12 < Wg / (360 / P) < 0.31.

[0007] According to the same configuration, since the angle of the groove width at the radially outer end of the groove symmetrically formed in the circumferential direction from the magnetic pole center is defined as Wg, and the number of the magnetic pole portions is defined as P, and it is set to satisfy 0.12 < Wg / (360 / P) < 0.31, a large detent torque can be ensured. That is, as shown in FIG. 4, since it is set to satisfy 0.12 < Wg / (360 / P) < 0.31, a larger detent torque can be obtained compared to the case where 0.12 < Wg / (360 / P) < 0.31 is not satisfied.

[0008] A motor (10) that solves the above problem is a motor that includes: an annular stator (12) having a plurality of teeth (16) extending circumferentially toward an axial center (L) and windings (18) wound around the teeth; a rotor core (22) rotatably accommodated inside the stator; and a rotor (13) having a plurality of permanent magnets (23, 32, 33, 36, 37) arranged circumferentially inside the rotor core, the rotor (13) having a plurality of magnetic pole portions (22b) formed in the circumferential direction by the plurality of permanent magnets on the surface of the rotor core facing the stator, the magnetic pole portions having grooves (22c, 31) recessed radially inward or holes with closed radial outer ends, and the total torque generated by specific teeth among the plurality of teeth that have the same angle relative to the magnetic pole portions at the cogging peak position is set to be within a range of 80% to 120% of the cogging torque.

[0009] With this configuration, the total torque generated by specific teeth that have the same angle relative to the magnetic pole portion at the cogging peak position is set to be within the range of 80% to 120% of the cogging torque, thereby enabling a large detent torque to be obtained. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a partial cross-sectional view of a motor according to an embodiment. [Diagram 2] FIG. 2 is a partial plan view of the motor according to the embodiment. [Diagram 3] FIG. 4 is a diagram showing angle-torque characteristics of a motor in one embodiment. [Figure 4] FIG. 4 is a diagram showing Wg / (360 / P)-detent torque characteristics of a motor in one embodiment. [Diagram 5] FIG. 4 is a diagram showing Wg / (360 / P)-average torque characteristics of a motor in one embodiment. [Figure 6] FIG. 4 is a diagram showing Wk / (2×Wr+Wg)-detent torque characteristics of a motor in one embodiment. [Figure 7] FIG. 4 is a diagram showing Z / G-detent torque characteristics of a motor in one embodiment. [Figure 8] FIG. 4 is a Wu / (360 / P)-detent torque characteristic diagram of a motor in one embodiment. [Figure 9] FIG. 4 is a Wu / (360 / P)-average torque characteristic diagram of a motor in one embodiment. [Figure 10] FIG. 4 is a Wk / (360 / S)-detent torque characteristic diagram of a motor in one embodiment. [Figure 11] FIG. 11 is a partial plan view of a motor according to another embodiment. [Figure 12] FIG. 11 is a Wa-detent torque characteristic diagram of a motor in another example. [Figure 13] FIG. 11 is a partial plan view of a motor according to another embodiment. [Figure 14] FIG. 11 is a diagram showing Wb-detent torque characteristics of a motor in another example. [Figure 15] FIG. 11 is a diagram showing Wb-average torque characteristics of a motor in another example. [Figure 16] FIG. 11 is a partial plan view of a motor according to another embodiment. [Figure 17] FIG. 11 is a (2×Wr1+Wg) / (2×Wr2+Wg)-average torque characteristic diagram of a motor in another example. [Figure 18] FIG. 11 is a (2×Wr1+Wg) / (2×Wr2+Wg)-detent torque characteristic diagram of a motor in another example. [Figure 19] FIG. 11 is a graph showing the angle-torque characteristics of a motor in a further example. [Figure 20] FIG. 11 is a (2×Wr1+Wg) / (2×Wr2+Wg)-ripple rate characteristic diagram of a motor in another example. [Figure 21] FIG. 11 is a partial plan view of a motor according to another embodiment. [Figure 22] FIG. 11 is a partial plan view of a motor according to another embodiment. [Diagram 23] FIG. 11 is a graph showing the (Wgs-Wg)-average torque characteristics of a motor in another example. [Figure 24] FIG. 11 is a partial plan view of a motor according to another embodiment. [Diagram 25] FIG. 11 is a partial plan view of a motor according to another embodiment. [Figure 26] FIG. 11 is a partial plan view of a motor according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of a motor will be described with reference to the drawings. Note that in the drawings, for the sake of convenience, some of the configuration may be exaggerated or simplified. Furthermore, the dimensional ratios of each part may differ from the actual ratios.

[0012] (Configuration of motor 10) 1, the motor 10 of this embodiment is an embedded magnet type brushless motor. The motor 10 includes an annular stator 12 fixed to the inner circumferential surface of a motor housing 11, and a rotor 13 rotatably accommodated inside the stator 12.

[0013] (Configuration of stator 12) The stator 12 has a cylindrical stator core 14, and the outer peripheral surface of the stator core 14 is fixed to the motor housing 11. The stator core 14 has an annular portion 15 and a plurality of teeth 16 in the circumferential direction extending radially inward from the annular portion 15 toward the axial center L. The outer diameter of the stator core 14 in this embodiment is set to 55 mm.

[0014] The teeth 16 are arranged at equal angular intervals. The stator core 14 of this embodiment has 12 teeth 16. That is, the number of slots of the stator 12, which is the same as the number of teeth 16 of this embodiment, is "12". The stator core 14 of this embodiment is made up of a plurality of split cores 17 in which the annular portion 15 is divided for each tooth 16. In the stator core 14, for example, an insulator will be attached to each of the split cores 17, but in the drawing, the stator core 14 is shown diagrammatically without showing the insulators.

[0015] The teeth 16 also have umbrella portions 16a protruding in both circumferential directions at their radially inner ends. The radially inner end faces of the teeth 16, in other words, the radially inner end faces of the umbrella portions 16a, are arcuate surfaces centered on the axial center L.

[0016] The stator 12 also has three-phase windings 18 wound around the teeth 16. The windings 18 are wound in a concentrated manner around each of the teeth 16 so as to be disposed between the teeth 16. The stator 12 generates a rotating magnetic field when a three-phase driving current is supplied to the windings 18.

[0017] (Configuration of rotor 13) The rotor 13 has a rotating shaft 21 rotatably provided about an axial center L, a rotor core 22 fixed to the outer periphery of the rotating shaft 21, and a plurality of permanent magnets 23 arranged in the circumferential direction inside the rotor core 22. The rotating shaft 21 is rotatably supported, for example, by an end housing (not shown) via a bearing (not shown).

[0018] The rotor core 22 is formed by stacking a plurality of disk-shaped electromagnetic steel sheets in the axial direction. The thickness of the electromagnetic steel sheets is set to, for example, 0.25 mm to 0.7 mm, and in this embodiment, electromagnetic steel sheets having a thickness of 0.5 mm are used. The outer diameter of the rotor core 22 in this embodiment is set to 30.8 mm.

[0019] The rotor core 22 has a plurality of magnet accommodating portions 22a in the circumferential direction. In this embodiment, the magnet accommodating portions 22a are formed in a U-shape that is open on the radially outer side. The U-shape here refers to a shape in which the radially inner side is rounded and curved when viewed in the axial direction. The magnet accommodating portions 22a in this embodiment are formed in a shape in which both end portions are spaced apart from each other toward the tip. The multiple magnet accommodating portions 22a are provided at equal angular intervals. Moreover, the rotor core 22 in this embodiment has eight magnet accommodating portions 22a.

[0020] The permanent magnet 23 is accommodated and arranged in the magnet accommodating portion 22a. The permanent magnet 23 in this embodiment is made of a samarium iron-based bonded magnet, and is arranged so as to fill the magnet accommodating portion 22a. That is, the permanent magnet 23 has the same shape as the magnet accommodating portion 22a, and is arranged in a U-shape with an open radially outward side. As a result, a plurality of magnetic pole portions 22b are formed in the circumferential direction by the plurality of permanent magnets 23 on the surface of the rotor core 22 facing the stator 12. Note that the rotor 13 in this embodiment is an embedded magnet type in which the permanent magnet 23 is arranged in each of the magnetic pole portions 22b, and the number of the magnetic pole portions 22b and the number of the permanent magnets 23 are the same. That is, the number of magnetic poles of the rotor 13, which is the same as the number of the magnetic pole portions 22b in this embodiment, is "8".

[0021] (Detailed configuration of groove 22c, etc.) Here, as shown in FIG. 2, the magnetic pole portion 22b has a groove 22c recessed radially inward. In other words, the rotor core 22 has a groove 22c recessed radially inward for each magnetic pole portion 22b. The grooves 22c are formed symmetrically in the circumferential direction from the magnetic pole center, which is the circumferential center of the magnetic pole portion 22b. More specifically, the grooves 22c are formed symmetrically with respect to the d-axis on a straight line D that passes through the circumferential center of the magnetic pole portion 22b and extends radially. The grooves 22c are formed over the entire axial direction of the rotor core 22. The grooves 22c have a constant width at a pair of circumferential end faces. The radially outer end of the groove 22c is not chamfered with respect to the outer circumferential surface of the rotor core 22, and is formed as a so-called pin angle.

[0022] Moreover, for the motor 10 of the present embodiment, the angle of the groove width at the radially outer end of the groove 22c is defined as Wg, the number of magnetic pole portions 22b is defined as P, and it is set to satisfy 0.12 < Wg / (360 / P) < 0.31. Note that the unit of Wg is "°" (degree). Also, the angle referred to in the present embodiment is the angle centered on the axis center L. More specifically, it is the angle formed by the auxiliary line drawn from the axis center L to the target position. In the present embodiment, it is set to satisfy 0.12 < Wg / (360 / P) < 0.27. Further, in the present embodiment, it is set to satisfy 0.15 < Wg / (360 / P) < 0.27. Specifically, in the present embodiment, Wg is 7.8°, P is 8, and Wg / (360 / P) is set to 0.17.

[0023] Also, for the motor 10, the angle of the width at the radially inner end of the teeth 16 is defined as Wk, the angle of the width of the magnetic path portion 22d of the rotor core 22 that forms the magnetic path on the side in the circumferential direction of the groove 22c is defined as Wr, and it is set to satisfy 0.7 < Wk / (2×Wr + Wg) < 1.0. Note that the units of Wk and Wr are "°" (degree). Specifically, in the present embodiment, Wk is 19.5°, 2×Wr + Wg is 24.0°, and Wk / (2×Wr + Wg) is set to 0.81.

[0024] Also, for the motor 10, the angle when the minimum width in the teeth 16 is at the same radial position as the magnetic path portion 22d is defined as Wt, and it is set to satisfy 0.5×Wt < Wr < Wt.

[0025] Also, for the motor 10, the air gap, which is the gap between the teeth 16 and the rotor core 22, is defined as G, the radial depth of the groove 22c is defined as Z, and it is set to satisfy Z / G ≧ 0.75. Note that the units of G and Z are "mm". Specifically, in the present embodiment, G is 0.55 mm, Z is 1.15 mm, and Z / G is set to 2.1.

[0026] Further, the motor 10 is set such that, with the angle of the width obtained by combining the ends of the permanent magnets 23 adjacent in the circumferential direction being Wu, 0.44 < Wu / (360 / P) < 0.58 is satisfied. Note that the unit of Wu is "°" (degree). Specifically, in the present embodiment, Wu is 21.0°, and Wu / (360 / P) is set to 0.47.

[0027] Further, the motor 10 is set such that, with the angle of the width at the radially inner end of the teeth 16 being Wk and the number of teeth 16 being S, 0.57 < Wk / (360 / S) < 0.78 is satisfied. Specifically, in the present embodiment, Wk is 19.5°, S is 12, and Wk / (360 / S) is set to 0.65.

[0028] Also, the motor 10 of the present embodiment is set such that, at the cogging peak position, the total torque generated by the specific teeth 16 where the angular states of the plurality of teeth 16 with respect to the magnetic pole portions 22b are the same is within the range of 80% to 120% of the cogging torque. Note that this setting is realized by the respective configurations and shapes of the stator 12 and the rotor 13 described above.

[0029] Specifically, as shown in FIG. 3, the motor 10 generates torque of characteristic M1 as a whole. Note that since the motor 10 of the present embodiment has "12" slots and "8" magnetic poles, it generates torque of characteristic M1 that pulsates 24 times per one rotation of the rotor 13, in other words, a waveform with a period of 15°. Also, the plurality of teeth 16 are configured such that four teeth 16 at 90° intervals where the angular states with respect to the magnetic pole portions 22b are the same form one set, and the stator 12 as a whole has three sets of teeth 16. The three sets of teeth 16 generate torque of characteristics M2, M3, and M4 for each set. And at the angle T1 that is the cogging peak position, the torque of characteristic M2 generated by the specific one set of teeth 16 is set to be within the range H1 of 80% to 120% of the cogging torque, which is the maximum value of characteristic M1.

[0030] Moreover, the motor 10 of this embodiment is set so that the total torque generated by the specific teeth 16 at the cogging peak position is equal to the cogging torque. That is, the motor 10 of this embodiment is set so that the total torque generated by the specific teeth 16 at the cogging peak position is substantially equal to the cogging torque. In other words, the motor 10 of this embodiment is set so that the configurations and shapes of the stator 12 and the rotor 13 are set so that the total torque generated by the specific teeth 16 at the cogging peak position is equal to the cogging torque as much as possible. Moreover, the motor 10 of this embodiment is set so that the total torque generated by the specific teeth 16 at the cogging peak position, which have the same angle state with respect to the magnetic pole portion 22b among the multiple teeth 16, is within a range of 90% to 110% of the cogging torque.

[0031] In addition, the motor 10 of this embodiment is set so that at the cogging peak position, the total torque generated by the teeth 16 other than the specific tooth 16 among the multiple teeth 16 is within the range of -20% (minus 20%) to +20% of the cogging torque.

[0032] Specifically, at angle T1, which is the cogging peak position, the total torque of characteristics M3 and M4 generated by two sets of teeth 16 other than one specific set of teeth 16 is set to be within range H2 of -20% to +20% of the cogging torque.

[0033] Furthermore, the motor 10 of this embodiment is set so that the torque generated by one of the teeth 16 has a section where the torque remains at zero. Note that the section where the torque remains at zero is not limited to a section where the torque remains strictly at zero, but is a section where the torque remains substantially at zero, and includes, for example, a section where the torque remains at a small wave that is 1 / 10 or less of the maximum torque. Note that FIG. 3 illustrates, for example, section K where the torque remains at zero in the characteristic M2. The characteristic M2 is the torque generated by the four teeth 16, and the torque generated by one tooth 16 is 1 / 4 of the characteristic M2 at each angle.

[0034] Next, the operation of this embodiment will be described. When a three-phase drive current is supplied to the winding 18 of the stator 12, a rotating magnetic field is generated in the stator 12. Then, the rotor 13 rotates due to the rotating magnetic field. When the power supply to the winding 18 is stopped, the rotating magnetic field disappears and the rotor 13 stops. At this time, the rotor 13 stops at an angular position where it is magnetically stable with respect to the stator 12. In this state, a detent torque acts on the rotor 13.

[0035] Next, the effects of the above embodiment will be described below. (1) The magnetic pole portion 22b has a groove 22c recessed inward in the radial direction, and the groove 22c is formed symmetrically in the circumferential direction from the magnetic pole center, which is the center in the circumferential direction of the magnetic pole portion 22b. Let the angle of the groove width at the radially outer end of the groove 22c be Wg, and the number of magnetic pole portions 22b be P. It is set to satisfy 0.12 < Wg / (360 / P) < 0.31. Therefore, a large detent torque can be ensured. Specifically, by providing the groove 22c, the change in the circumferential magnetic flux density in the air gap can be increased, and a larger detent torque can be ensured.

[0036] That is, as shown in FIG. 4, since it is set to satisfy 0.12 < Wg / (360 / P) < 0.31, a larger detent torque can be obtained compared to the case where 0.12 < Wg / (360 / P) < 0.31 is not satisfied. Note that the characteristic A1 in FIG. 4 is a waveform obtained by experiment or calculation, and shows the change in the detent torque when Wg / (360 / P) is changed.

[0037] Also, as shown in FIG. 5, since it is set to satisfy 0.12 < Wg / (360 / P) < 0.31, a large average torque can be obtained. Note that the characteristic A2 in FIG. 5 is a waveform obtained by experiment or calculation, and shows the change in the average torque when Wg / (360 / P) is changed.

[0038] (2) Since it is set to satisfy 0.12 < Wg / (360 / P) < 0.27, a larger average torque can be ensured while securing a large detent torque. That is, as shown in FIG. 5, since it is set to satisfy 0.12 < Wg / (360 / P) < 0.27, a larger average torque can be obtained compared to the case where Wg / (360 / P) does not satisfy 0.27.

[0039] Furthermore, in the present embodiment, Wg / (360 / P) is set to 0.17 and is set to satisfy 0.15 < Wg / (360 / P) < 0.27. In this way, when set to satisfy 0.15 < Wg / (360 / P) < 0.27, as shown in FIG. 4, a larger detent torque can be ensured.

[0040] (3) Let the angular width at the radially inner end of the tooth 16 be Wk, and the angular width of the magnetic path portion 22d of the rotor core 22 that forms the magnetic path on the circumferential side of the groove 22c be Wr. It is set to satisfy 0.7 < Wk / (2×Wr + Wg) < 1.0. Therefore, a large detent torque can be ensured.

[0041] That is, as shown in FIG. 6, since it is set to satisfy 0.7 < Wk / (2×Wr + Wg) < 1.0, a large detent torque can be obtained compared to the case where 0.7 < Wk / (2×Wr + Wg) < 1.0 is not satisfied. Note that the characteristic A3 in FIG. 6 is a waveform obtained by experiment or calculation and shows the change in the detent torque when Wk / (2×Wr + Wg) is changed.

[0042] (4) Let the angular width of the magnetic path portion 22d of the rotor core 22 that forms the magnetic path on the circumferential side of the groove 22c be Wr, and the angle when the minimum width of the tooth 16 is at the same radial position as the magnetic path portion 22d be Wt. It is set to satisfy 0.5×Wt < Wr < Wt. Therefore, while suppressing a decrease in the average torque due to magnetic saturation of the magnetic path portion 22d, a large detent torque can be ensured.

[0043] (5) Let the air gap, which is the gap between the teeth 16 and the rotor core 22, be G, and let the radial depth of the groove 22c be Z. It is set so as to satisfy Z / G ≥ 0.75. Therefore, by suppressing the leakage magnetic flux in the groove 22c, the magnetic flux can be concentrated in the magnetic path portion 22d, and the change in the magnetic flux density in the circumferential direction of the air gap can be increased. As a result, a large detent torque can be ensured.

[0044] That is, as shown in FIG. 7, since it is set so as to satisfy Z / G ≥ 0.75, a larger detent torque can be obtained compared to the case where Z / G < 0.75 is not satisfied. Note that the characteristic A4 in FIG. 7 is a waveform obtained by experiment or calculation, and shows the change in the detent torque when Z / G is changed. Also, by setting it so as to satisfy Z / G ≥ 1.0, a larger detent torque can be ensured and the variation in the detent torque can be suppressed. Furthermore, by setting it so as to satisfy Z / G ≥ 1.5, an even larger detent torque can be ensured and the variation in the detent torque can be further suppressed.

[0045] (6) Since the permanent magnets 23 arranged in each of the magnetic pole portions 22b are arranged in a U shape with an open outer side in the radial direction, it is possible to easily secure a space for providing the groove 22c. That is, when the permanent magnets are arranged in an I shape extending in a direction orthogonal to the radial direction, it is difficult to secure a space for providing the groove 22c. In contrast, the groove 22c can be easily provided.

[0046] (7) Let the number of the magnetic pole portions 22b be P, and let the angle of the combined width of the ends of the circumferentially adjacent permanent magnets 23 be Wu. It is set so as to satisfy 0.44 < Wu / (360 / P) < 0.58. Therefore, a large average torque can be ensured while ensuring a large detent torque.

[0047] That is, as shown in FIG. 8, since it is set to satisfy 0.44 < Wu / (360 / P) < 0.58, a large detent torque can be obtained. Note that the characteristic A5 in FIG. 8 is a waveform obtained by experiment or calculation, and shows the change in detent torque when Wu / (360 / P) is changed.

[0048] Also, as shown in FIG. 9, since it is set to satisfy 0.44 < Wu / (360 / P) < 0.58, a larger average torque can be obtained compared to the case where 0.44 < Wu / (360 / P) < 0.58 is not satisfied. Also, the characteristic A6 in FIG. 9 is a waveform obtained by experiment or calculation, and shows the change in average torque when Wu / (360 / P) is changed.

[0049] (8) Let the angular width at the radially inner end of the tooth 16 be Wk, and the number of teeth 16 be S. It is set to satisfy 0.57 < Wk / (360 / S) < 0.78. Therefore, a large detent torque can be ensured.

[0050] That is, as shown in FIG. 10, since it is set to satisfy 0.57 < Wk / (360 / S) < 0.78, a larger detent torque can be obtained compared to the case where 0.57 < Wk / (360 / S) < 0.78 is not satisfied. Note that the characteristic A7 in FIG. 10 is a waveform obtained by experiment or calculation, and shows the change in detent torque when Wk / (360 / S) is changed.

[0051] (9) At the cogging peak position, the total torque generated by a specific tooth 16 where the angular states of the plurality of teeth 16 with respect to the magnetic pole portion 22b are the same is set to be within the range H1 of 80% to 120% of the cogging torque. By doing so, a large detent torque can be obtained. When the total torque generated by the specific tooth 16 at the cogging peak position is set to coincide with the cogging torque, a larger detent torque can be obtained.

[0052] (10) At the cogging peak position, the total torque generated by the teeth 16 other than the specific tooth 16 among the plurality of teeth 16 is set to be within the range H2 of -20% to +20% of the cogging torque. By doing so, a large detent torque can be obtained.

[0053] (11) It is set such that the torque generated by one tooth 16 among the plurality of teeth 16 has a section where it transitions to 0. By doing so, a large detent torque can be obtained. Note that the descriptions regarding the above effects (9) to (11) are the methods for calculating the effects for the rotor 13. For example, for a specification where the stator 12 has grooves, it is necessary to obtain the effects for the rotor 13 in a state where the stator 12 has no grooves.

[0054] (12) The motor 10 is set such that, with the angular width at the radially inner end of the tooth 16 being Wk and the number of teeth 16 being S, 0.57 < Wk / (360 / S) < 0.78 is satisfied. Therefore, a large detent torque can be ensured.

[0055] That is, as shown in FIG. 10, since it is set to satisfy 0.57 < Wk / (360 / S) < 0.78, a larger detent torque can be obtained compared to the case where 0.57 < Wk / (360 / S) < 0.78 is not satisfied. Note that the characteristic A7 in FIG. 10 is a waveform obtained through experiments or calculations, and shows the change in the detent torque when Wk / (360 / S) is changed.

[0056] This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range. · In the above embodiment, the groove 22c is assumed to have a constant width at a pair of end faces in the circumferential direction, but it is not limited to this, and the end faces in the circumferential direction may be inclined so that the width becomes wider as it goes toward the radially inner side.

[0057] For example, it may be modified as shown in Fig. 11. In this example (see Fig. 11), the groove 31 is inclined so that the circumferential end face 31a becomes wider as it approaches the radial inside. In this way, a large detent torque can be ensured. In detail, by inclining the end face 31a, it becomes possible to better control the flow of magnetic flux in the magnetic path portion 22d, and a larger detent torque can be ensured.

[0058] That is, as shown in Fig. 12, when the groove 31 is inclined so that the width of the circumferential end face 31a becomes wider toward the radially inward side, a larger detent torque can be obtained compared to other cases. Note that characteristic A8 in Fig. 12 is a waveform obtained by experiment or calculation, and shows the change in detent torque when the angle Wa at which the circumferential end face 31a of the groove 31 is inclined with respect to the above-mentioned straight line D (i.e., the d-axis) is changed. Also, in Fig. 12, the case in which the circumferential end face 31a of the groove 31 becomes wider toward the radially inward side is regarded as the negative side.

[0059] In the above embodiment, the end of the permanent magnet 23 has a shape that extends in a direction away from the circumferential end face of the groove 22c as it moves radially outward, but this is not limited to this, and the permanent magnet 23 may have a shape that has a thick portion that protrudes in a direction approaching the circumferential end face of the groove 22c.

[0060] For example, it may be modified as shown in Fig. 13. In this example (see Fig. 13), the end of the permanent magnet 32 ​​has a thick portion 32a that extends in a direction away from the circumferential end face of the groove 22c as it moves radially outward, but protrudes in a direction toward the circumferential end face of the groove 22c.

[0061] In this way, for example, leakage magnetic flux generated in the rotor core 22 arranged radially outward from the radially outer end face of the permanent magnet 32 ​​can be suppressed, thereby ensuring a large torque, and by providing a width for pole switching, it is possible to increase the change in magnetic flux density in the circumferential direction of the air gap, thereby ensuring a large average torque while ensuring a large detent torque.

[0062] That is, as shown in Fig. 14, if the angle Wb at which the circumferential end face of the thick portion 32a is inclined with respect to the above-mentioned straight line D (i.e., the d-axis) is 0° or less, a large detent torque can be ensured. Note that characteristic A9 in Fig. 14 is a waveform obtained by experiment or calculation, and shows the change in detent torque when the angle Wb at which the circumferential end face of the thick portion 32a is inclined with respect to the straight line D (i.e., the d-axis) is changed. In Fig. 14, the case where the circumferential end face of the thick portion 32a approaches the straight line D radially outward is regarded as the negative side.

[0063] Also, as shown in Fig. 15, if the angle Wb at which the circumferential end face of the thick portion 32a is inclined with respect to the aforementioned straight line D (i.e., the d-axis) is within the range of -20° (minus 20°) to 0°, a large average torque can be ensured. Note that the characteristic A10 in Fig. 15 is a waveform obtained by experiment or calculation, and shows the change in average torque when the angle Wb at which the circumferential end face of the thick portion 32a is inclined with respect to the straight line D (i.e., the d-axis) is changed. In Fig. 15, the case where the circumferential end face of the thick portion 32a approaches the straight line D toward the radially outward side is regarded as the negative side.

[0064] In the above embodiment, the rotor 13 is an embedded magnet type in which a permanent magnet 23 is arranged in each of the magnetic pole portions 22b, but this is not limited to this, and the rotor may be a consequent type in which a permanent magnet is arranged in every other magnetic pole portion in the circumferential direction.

[0065] For example, it may be modified as shown in Fig. 16. The rotor 13 in this example (see Fig. 16) is a consequent type in which the permanent magnets 33 are arranged alternately in the circumferential direction of the multiple magnetic pole portions 22b. The multiple magnetic pole portions 22b are formed by alternatingly arranging magnet pole portions 34 in which the permanent magnets 33 are arranged and non-magnet magnetic pole portions 35 in which the permanent magnets 33 are not arranged in the circumferential direction.

[0066] In this example, the magnet accommodating portion 22e in the rotor core 22 is formed in an I-shape extending in a direction perpendicular to the radial direction. The permanent magnets 33 accommodated in the magnet accommodating portion 22e are arranged in the I-shape extending in a direction perpendicular to the radial direction.

[0067] A portion of the rotor core 22 that forms a magnetic path on the circumferential side of the groove 22c in the magnet magnetic pole portion 34 forms a magnet magnetic path portion 22f, and a portion of the rotor core 22 that forms a magnetic path on the circumferential side of the groove 22c in the non-magnet magnetic pole portion 35 forms a non-magnet magnetic path portion 22g.

[0068] Furthermore, the rotor core 22 in this example has a flux barrier 22h that is a gap for blocking magnetic flux. The flux barrier 22h in this example is formed so as to communicate with both ends of the magnet accommodating portion 22e.

[0069] The flux barrier 22h is set so that the angle of the width of the magnet magnetic path portion 22f is Wr1 and the angle of the width of the non-magnet magnetic path portion 22g is Wr2, and the relationship (2×Wr1+Wg) / (2×Wr2+Wg)≦1.5 is satisfied. Specifically, in this example (see FIG. 16), 2×Wr1+Wg is 21.8°, 2×Wr2+Wg is 22.5°, and (2×Wr1+Wg) / (2×Wr2+Wg)=0.97 is satisfied. In this way, a large average torque and a large detent torque can be ensured. Also, the ripple rate can be suppressed to a small value.

[0070] That is, since the ratio is set so as to satisfy (2×Wr1+Wg) / (2×Wr2+Wg)≦1.5 as shown in Fig. 17, a large average torque can be obtained. Note that characteristic A11 in Fig. 17 is a waveform obtained by experiment or calculation, and shows the change in average torque when (2×Wr1+Wg) / (2×Wr2+Wg) is changed.

[0071] Also, as shown in Fig. 18, since the ratio is set so as to satisfy (2×Wr1+Wg) / (2×Wr2+Wg)≦1.5, a large detent torque can be obtained. Note that characteristics A12 and A13 in Fig. 18 are waveforms obtained by experiment or calculation, and show the change in detent torque when (2×Wr1+Wg) / (2×Wr2+Wg) is changed.

[0072] In this example, since the motor 10 has the magnet magnetic pole portion 34 and the non-magnet magnetic pole portion 35, two detent torque characteristics A12 and A13 are obtained according to the angle of the rotor 13. Specifically, as shown in FIG. 19, the torque characteristics Y1 and Y2 of the motor 10 having the magnet magnetic pole portion 34 and the non-magnet magnetic pole portion 35 have different peak values ​​according to the angles θ1 and θ2 of the rotor 13. The torque characteristic Y1 is the characteristic when (2×Wr1+Wg) / (2×Wr2+Wg)=0.97 in this example (see FIG. 16). The torque characteristic Y2 is the characteristic when (2×Wr1+Wg) / (2×Wr2+Wg)=1.5. When the rotor 13 has an angle θ1, the change in the detent torque when (2×Wr1+Wg) / (2×Wr2+Wg) is changed is the characteristic A12. Also, in the case of the rotor angle θ2, the change in the detent torque when (2×Wr1+Wg) / (2×Wr2+Wg) is changed is the characteristic A13. Therefore, it is preferable to set it so that, for example, (2×Wr1+Wg) / (2×Wr2+Wg)≦1.22 is satisfied. In this way, even in the consequent type, it is possible to reduce the difference in the magnetic flux flow between the magnet magnetic pole portion 34 and the non-magnet magnetic pole portion 35, and it is possible to obtain a large detent torque with a small difference in both characteristics A12 and A13. As a result, for example, the rotor 13 can be stably positioned and held at a small angle (360° / 24 in this example). That is, the motor 10 can have a high resolution. Note that (2×Wr1+Wg) / (2×Wr2+Wg) is closer to 1 than 1.22, and it is more preferable that it is closer to 1.

[0073] Also, as shown in FIG. 20, since it is set to satisfy (2×Wr1+Wg) / (2×Wr2+Wg)≦1.5, the ripple rate can be suppressed to a small value. Note that the characteristic A14 in FIG. 20 is a waveform obtained by experiment or calculation, and shows the change in the ripple rate when (2×Wr1+Wg) / (2×Wr2+Wg) is changed.

[0074] Also, in the case of this example (see FIG. 16), Wr1 is adopted as Wr in 0.7<Wk / (2×Wr+Wg)<1.0 described above, and it is set to Wk / (2×Wr+Wg)=0.89. Also, in the case of this example (see FIG. 16), for Wr in 0.5×Wt<Wr<Wt described above, the larger Wr2 is adopted.

[0075] Also, for example, as shown in FIG. 21, it may be changed. The rotor 13 in this example (see FIG. 21) is a consequent-pole type in which permanent magnets 36 are arranged every other one in the circumferential direction in a plurality of magnetic pole portions 22b. The plurality of magnetic pole portions 22b are formed by alternately arranging a magnet magnetic pole portion 34 in which a permanent magnet 36 is arranged and a non-magnet magnetic pole portion 35 in which a permanent magnet 36 is not arranged in the circumferential direction.

[0076] The magnet housing portion 22j in the rotor core 22 of this example is formed in a U shape with an open outer diameter. And the permanent magnet 36 housed in the magnet housing portion 22j is arranged in a U shape with an open outer diameter.

[0077] Also, the rotor core 22 of this example has a flux barrier 22k which is a gap for blocking magnetic flux. The flux barrier 22k of this example is independent of the magnet housing portion 22j, and is recessed radially inward from the outer peripheral surface of the rotor core 22.

[0078] The flux barrier 22k is set so that the angle of the width of the magnet magnetic path portion 22f is Wr1 and the angle of the width of the non-magnet magnetic path portion 22g is Wr2, and the relationship (2×Wr1+Wg) / (2×Wr2+Wg)≦1.5 is satisfied. Specifically, in this example (see FIG. 21), 2×Wr1+Wg is 22.7°, 2×Wr2+Wg is 21.0°, and (2×Wr1+Wg) / (2×Wr2+Wg)=1.08 is satisfied. Even in this way, it is possible to ensure a large average torque and a large detent torque. Also, the ripple rate can be suppressed to a small value.

[0079] In the above embodiment, the radially inner end faces of the teeth 16, in other words the radially inner end faces of the umbrella portions 16a, are simple arc surfaces, but are not limited to this and may have tooth grooves.

[0080] 22, the teeth 16 have teeth grooves 16b recessed radially outward from the radially inner end of the circumferential center of the teeth 16. In this way, it is possible to ensure even greater detent torque.

[0081] In this example, the groove width angle at the radially inner end of the tooth groove 16b is designated as Wgs, and is set to satisfy Wgs-Wg<0. The unit of Wgs is "°" (degrees). Specifically, in this example (see FIG. 22), Wg is 8.2°, Wgs is 4.7°, and Wgs-Wg is set to -3.5°. Therefore, a large average torque can be ensured.

[0082] That is, since the setting is made so as to satisfy Wgs-Wg<0 as shown in Fig. 23, a large average torque can be obtained. Note that characteristic A15 in Fig. 23 is a waveform obtained by experiment or calculation, and shows the change in average torque when Wgs-Wg is changed.

[0083] 24, for example, the tooth grooves 16b may be inclined so that the width of the circumferential end faces 16c becomes narrower toward the radially outer side, thereby making it possible to ensure a larger average torque.

[0084] In the above embodiment, the grooves 22c are provided in the same number as the magnetic pole portions 22b, and are provided in each of all the magnetic pole portions 22b. However, the present invention is not limited to this and may be changed to another configuration.

[0085] For example, as shown in Fig. 25, the grooves 22c may be provided in half the number of the magnetic pole portions 22b, and may be provided on every other magnetic pole portion 22b arranged in the circumferential direction. Specifically, for example, the grooves 22c may be provided on all the magnetic pole portions 22b constituting the N pole, and may not be provided on the magnetic pole portions 22b constituting the S pole.

[0086] In the above embodiment, the magnet storage section 22a is formed in a U-shape and the permanent magnet 23 is arranged in a U-shape, but this is not limited thereto, and the magnet storage section 22a may be formed in a V-shape and the permanent magnet may be arranged in a V-shape. The V-shape here refers to a shape in which the radially inner side is not curved when viewed in the axial direction. In this case, for example, the permanent magnet may be arranged in a V-shape by combining two rectangular parallelepiped shapes. In the above embodiment, the permanent magnet 23 is made of a samarium-iron bonded magnet, but this is not limited thereto, and it may be a rare earth sintered magnet such as a neodymium magnet.

[0087] Also, as shown in FIG. 26, the magnet accommodating portion 22m may be formed in an I-shape extending in a direction perpendicular to the radial direction, and the permanent magnets 37 accommodated in the magnet accommodating portion 22m may be arranged in an I-shape extending in a direction perpendicular to the radial direction. This example is an embedded magnet type in which the number of magnetic pole portions 22b and the number of permanent magnets 37 are the same. The rotor core 22 in this example also has flux barriers 22n, which are gaps for blocking magnetic flux. The flux barriers 22n are formed in communication with both ends of the magnet accommodating portion 22m. The flux barriers 22n extend radially outward from both ends of the magnet accommodating portion 22m to secure a space for providing grooves 22c on the radially outer side of the permanent magnets 37.

[0088] In the above embodiment, the groove 22c is configured to open to the radially outer side of the rotor core 22, but this is not limited thereto, and may be changed to, for example, a hole having a shape recessed radially inward and a closed radially outer end. In other words, the groove 22c may be changed to a hole having another configuration that blocks magnetic flux in a substantially similar manner.

[0089] In the above embodiment, the stator core 14 is made up of a plurality of split cores 17 in which the annular portion 15 is divided for each tooth 16, but this is not limited to this, and the stator core may have an annular portion 15 that is not divided.

[0090] In the above embodiment, the rotor has 12 teeth 16 and 8 magnetic pole portions 22b, but the present invention is not limited to this and the number of teeth 16 and the number of magnetic pole portions 22b may be changed. In other words, the number of slots and the number of magnetic poles may be changed.

[0091] The features of the present invention are as follows. [1] An annular stator (12) having a plurality of teeth (16) extending in the circumferential direction toward the axis center (L) and a winding (18) wound around the teeth, a rotor core (22) rotatably accommodated inside the stator, and a plurality of permanent magnets (23, 32, 33, 36, 37) provided inside the rotor core in the circumferential direction. A rotor (13) in which a plurality of magnetic pole portions (22b) are formed in the circumferential direction by the plurality of permanent magnets on the opposing surface of the rotor core with respect to the stator. The motor (10) is provided, wherein the magnetic pole portion has a groove (22c, 31) recessed inward in the radial direction, the groove is symmetrically formed in the circumferential direction from the magnetic pole center which is the circumferential center of the magnetic pole portion, and the angle of the groove width at the radially outer end of the groove is Wg, and the number of the magnetic pole portions is P. The motor is set so as to satisfy 0.12 < Wg / (360 / P) < 0.31.

[0092] [2] The motor according to [1] above, which is set so as to satisfy 0.12 < Wg / (360 / P) < 0.27. [3] The angle of the width at the radially inner end of the teeth is Wk, and the angle of the width of the magnetic path portion (22d) of the rotor core constituting the magnetic path on the circumferential side of the groove is Wr. The motor according to [1] or [2] above is set so as to satisfy 0.7 < Wk / (2×Wr + Wg) < 1.0.

[0093] [4] The angle of the width of the magnetic path portion of the rotor core constituting the magnetic path on the circumferential side of the groove is Wr, and the angle when the minimum width of the teeth is at the same radial position as the magnetic path portion is Wt. The motor according to any one of [1] to [3] above is set so as to satisfy 0.5×Wt < Wr < Wt.

[0094] [5] The air gap between the teeth and the rotor core is G, and the radial depth of the groove is Z. The motor according to any one of [1] to [4] above is set so as to satisfy Z / G ≧ 0.75.

[0095] [6] The permanent magnet disposed in each of the magnetic pole portions is arranged in a U-shape or V-shape with an open outer diameter in the radial direction, the motor according to any one of [1] to [5] above. [7] Let the number of the magnetic pole portions be P, and let the angle of the width obtained by combining the ends of the adjacent permanent magnets in the circumferential direction be Wu. It is set so as to satisfy 0.44 < Wu / (360 / P) < 0.58, the motor according to [6] above.

[0096] [8] The groove (31) is inclined such that the circumferential end surface (31a) becomes wider as it goes toward the inner side in the radial direction, the motor according to any one of [1] to [7] above. [9] The end of the permanent magnet (32) has a thick portion (32a) that extends in a direction away from the circumferential end surface of the groove while protruding in a direction approaching the circumferential end surface of the groove as it goes toward the outer side in the radial direction, the motor according to any one of [1] to [8] above.

[0097]

[10] The permanent magnets (33, 36) are arranged every other one in the circumferential direction in the plurality of magnetic pole portions. The plurality of magnetic pole portions are formed by alternately arranging a magnet magnetic pole portion (34) where the permanent magnet is arranged and a non-magnet magnetic pole portion (35) where the permanent magnet is not arranged in the circumferential direction. Let the angle of the width of the magnet magnetic path portion (22f) of the rotor core that constitutes the magnetic path on the circumferential side of the groove in the magnet magnetic pole portion be Wr1, and let the angle of the width of the non-magnet magnetic path portion (22g) of the rotor core that constitutes the magnetic path on the circumferential side of the groove in the non-magnet magnetic pole portion be Wr2. A flux barrier (22h, 22k) is set so as to satisfy (2×Wr1 + Wg) / (2×Wr2 + Wg) ≤ 1.5, the motor according to any one of [1] to [5], [8], and [9] above.

[0098]

[11] The teeth have a tooth groove (16b) recessed from the inner end in the radial direction of the center in the circumferential direction of the teeth toward the outer side in the radial direction, the motor according to any one of [1] to

[10] above.

[0099]

[12] The motor described in

[11] above, wherein the groove width angle at the radially inner end of the tooth groove is Wgs, and is set so as to satisfy Wgs-Wg<0.

[13] A motor comprising: an annular stator (12) having a plurality of teeth (16) extending circumferentially toward an axial center (L) and windings (18) wound around the teeth; a rotor core (22) rotatably accommodated inside the stator; and a rotor (13) having a plurality of permanent magnets (23, 32, 33, 36, 37) arranged circumferentially inside the rotor core, the rotor core having a surface facing the stator on which a plurality of magnetic pole portions (22b) are formed in the circumferential direction by the plurality of permanent magnets, the magnetic pole portions having grooves (22c, 31) recessed radially inward or holes with closed radially outer ends, the total torque generated by specific teeth among the plurality of teeth that have the same angle with respect to the magnetic pole portions at a cogging peak position is set within a range of 80% to 120% of the cogging torque.

[0100]

[14] The motor described in

[13] above, wherein the total torque generated by the specific teeth at the cogging peak position is set to match the cogging torque.

[15] The motor described in

[13] or

[14] above, wherein at the cogging peak position, the total torque generated by teeth other than the specific tooth among the plurality of teeth is set to be within the range of -20% to +20% of the cogging torque.

[0101]

[16] The motor described in any one of

[13] to

[15] above, wherein the torque generated by one of the plurality of teeth is set to have a section during which the torque remains at zero. [Explanation of symbols]

[0102] 10...motor, 12...stator, 13...rotor, 14...stator core, 16...teeth, 16b...teeth groove, 16c...end surface, 18...winding, 22...rotor core, 22b...magnetic pole portion, 22c...groove, 22d...magnetic path portion, 22f...magnetic magnetic path portion, 22g...non-magnetic magnetic path portion, 22h...flux barrier, 22k...flux barrier, 23...permanent magnet, 31...groove, 31a...end surface, 32...permanent magnet, 32a...thick portion, 33...permanent magnet, 34...magnetic pole portion, 35...non-magnetic pole portion, 36...permanent magnet, 37...permanent magnet.

Claims

1. A ring-shaped stator (12) having a plurality of teeth (16) extending in a circumferential direction toward an axial center (L) and windings (18) wound around the teeth; a rotor (13) having a rotor core (22) rotatably accommodated inside the stator, and a plurality of permanent magnets (23, 32, 33, 36, 37) provided in a circumferential direction inside the rotor core, the plurality of permanent magnets forming a plurality of magnetic pole portions (22b) in the circumferential direction on a surface of the rotor core facing the stator, The magnetic pole portion has a groove (22c, 31) recessed radially inward, The grooves are formed symmetrically in the circumferential direction from a magnetic pole center, which is the circumferential center of the magnetic pole portion, The groove width angle at the radially outer end of the groove is Wg, The number of the magnetic pole parts is P, 0.12<Wg / (360 / P)<0.31 It is set to satisfy Motor.

2. 0.12<Wg / (360 / P)<0.27 It is set to satisfy The motor according to claim 1 .

3. a width angle of the tooth at a radially inner end portion is Wk; The width angle of the magnetic path portion (22d) of the rotor core that constitutes a magnetic path on the circumferential side of the groove is Wr, 0.7<Wk / (2×Wr+Wg)<1.0 It is set to satisfy The motor according to claim 1 .

4. a width angle of a magnetic path portion of the rotor core that constitutes a magnetic path on a circumferential side of the groove is represented by Wr; Let Wt be the angle when the minimum width of the tooth is at the same radial position as the magnetic path portion, 0.5×Wt<Wr<Wt It is set to satisfy The motor according to claim 1 .

5. An air gap between the teeth and the rotor core is G, The radial depth of the groove is Z, Z / G≧0.75 It is set to satisfy The motor according to claim 1 .

6. The permanent magnets arranged in each of the magnetic pole portions are arranged in a U-shape or a V-shape with an open radially outward side. The motor according to claim 1 .

7. The number of the magnetic pole parts is P, The angle of the width of the ends of the permanent magnets adjacent in the circumferential direction is Wu, 0.44<Wu / (360 / P)<0.58 It is set to satisfy 7. The motor according to claim 6.

8. The groove (31) is inclined so that the width of the circumferential end surface (31a) becomes wider toward the radially inner side. The motor according to claim 1 .

9. The end of the permanent magnet (32) has a thick portion (32a) that extends in a direction away from the circumferential end surface of the groove as it moves radially outward, but protrudes in a direction toward the circumferential end surface of the groove. The motor according to claim 1 .

10. The permanent magnets (33, 36) are arranged alternately in the circumferential direction of the plurality of magnetic pole portions, The plurality of magnetic pole portions are formed by alternately arranging magnetic pole portions (34) in which the permanent magnets are arranged and non-magnetic pole portions (35) in which the permanent magnets are not arranged in the circumferential direction, a width angle of a magnet magnetic path portion (22f) of the rotor core that forms a magnetic path on a circumferential side of the groove in the magnet magnetic pole portion is Wr1; The width angle of the non-magnetic magnetic path portion (22g) of the rotor core that constitutes a magnetic path on the circumferential side of the groove in the non-magnetic magnetic pole portion is Wr2, (2×Wr1+Wg) / (2×Wr2+Wg)≦1.5 The flux barriers (22h, 22k) are set so as to satisfy The motor according to claim 1 .

11. The teeth have teeth grooves (16b) recessed radially outward from a radially inner end of the circumferential center of the teeth. The motor according to claim 1 .

12. a groove width angle at a radially inner end portion of the tooth groove is defined as Wgs, Wgs-Wg<0 It is set to satisfy 12. The motor according to claim 11.

13. A ring-shaped stator (12) having a plurality of teeth (16) extending in a circumferential direction toward an axial center (L) and windings (18) wound around the teeth; a rotor (13) having a rotor core (22) rotatably accommodated inside the stator, and a plurality of permanent magnets (23, 32, 33, 36, 37) provided in a circumferential direction inside the rotor core, and a plurality of magnetic pole portions (22b) formed in the circumferential direction by the plurality of permanent magnets on a surface of the rotor core facing the stator, The magnetic pole portion has a groove (22c, 31) recessed radially inward, or a hole having a closed radially outer end of the groove, At a cogging peak position, a total torque generated by a specific tooth among the plurality of teeth, which has the same angle state with respect to the magnetic pole portion, is set to be within a range of 80% to 120% of the cogging torque. Motor.

14. At the cogging peak position, the total torque generated by the specific teeth is set to be equal to the cogging torque.

14. The motor according to claim 13.

15. At a cogging peak position, a total torque generated by teeth other than the specific teeth among the plurality of teeth is set to be within a range of −20% to +20% of the cogging torque.

14. The motor according to claim 13.

16. The torque generated by one of the plurality of teeth is set to have a section in which the torque is zero.

14. The motor according to claim 13.

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