Motor

Abstract

To provide a motor increased in cogging torque.SOLUTION: A motor 1 comprises: a shaft 30; a magnetic member 30 having: a core 2 including: an annular portion 2a disposed coaxially with the shaft 30; and a plurality of spokes 2b extending in a radial direction nm from the annular portion 2a; and a coil 3 wound around the spokes 2b; and a magnet 11 annularly disposed coaxially with the shaft 30. In the radial direction nm, a magnetic member 20 and the magnet 11 are arranged one inside the other. The end, in the radial direction nm, of each of the plurality of spokes 2b and the magnet 11 are opposite to each other in the radial direction nm. At an end, in the radial direction nm, of each of the plurality of spokes 2b, the core 2 has a pair of magnetic pole portions 2c extending in both sides of a circumferential direction xy. A magnetic pole portion 2c-1x on one side x in the circumferential direction xy of the pair of magnetic pole portions 2c-1 of at least one of the plurality of spokes 2b has high magnetic resistance compared with a magnetic pole portion 2c-1y on the other side y.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] As a DC motor used in information devices, in-vehicle applications, etc., for example, Patent Document 1 describes a structure in which magnets are not integrally formed but are composed of four magnets. Further, Patent Document 2 describes a structure using integrally formed magnets. In such a DC motor, further reduction of vibration is desired, and usually, cogging torque, which is one of the causes of vibration, is suppressed as much as possible.

[0003] On the other hand, for motors used in electric doors and electric hatchbacks of vehicles, it is desired that the rotation of the motor shaft be suppressed when the motor stops. In order to suppress the rotation of the motor shaft at the time of stopping, it is effective to rather increase the cogging torque.

[0004] As a technique for increasing the cogging torque, the technique described in Patent Document 3 is disclosed. The technique described in Patent Document 3 includes four field magnetic poles and an armature core having five tooth portions extending radially from a shaft portion and facing the field magnetic poles, and a groove in which an air gap between the field magnetic poles becomes large is provided at a central portion of the opening angle of the outer peripheral surface of the tip of each tooth portion of the armature core. Due to the presence of this air gap, when no driving voltage is applied, the facing positional relationship between the field magnetic poles and the armature core becomes a stable state, and the cogging torque is increased.

[0005] However, in the technique described in Patent Document 3, the number of field magnetic poles is limited to four, and the number of tooth portions of the armature core is limited to five. Also, the effect of increasing the cogging torque by this technique is still not sufficient, and it is desired that a larger cogging torque be generated.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, one object of the present invention is to provide a motor in which an increase in cogging torque is achieved.

Means for Solving the Problems

[0008] The above problems are solved by the following present invention. That is, the motor of the present invention includes a shaft, a core having an annular portion arranged coaxially with the shaft and a plurality of spokes extending radially from the annular portion, and a magnetic member having a coil wound around the spokes, a magnet arranged annularly coaxially with the rotor shaft, and is provided with the magnetic member and the magnet are arranged such that one is disposed inside the other in the radial direction, the radial end portions of each of the plurality of spokes face the magnet in the radial direction, the core has a pair of magnetic pole portions extending in both circumferential directions at the radial end portions of each of the plurality of spokes, in the pair of magnetic pole portions of at least one of the plurality of spokes, the magnetic pole portion on one side in the circumferential direction has a larger magnetic resistance than the magnetic pole portion on the other side in the circumferential direction.

[0009] In the present invention, among the plurality of spokes, the spoke having the pair of magnetic pole portions with different magnetoresistances on one side and the other side in the circumferential direction is defined as the first spoke, and another spoke adjacent to the first spoke on the one side in the circumferential direction is defined as the second spoke. It is preferable that the magnetoresistance of the magnetic pole portion on the other side in the circumferential direction in the pair of magnetic pole portions of the second spoke is larger than that of the magnetic pole portion on the one side in the circumferential direction.

[0010] Also, in the present invention, another spoke adjacent to the second spoke on one side in the circumferential direction is defined as the third spoke. It is preferable that the magnetoresistance of the magnetic pole portion on the other side in the circumferential direction in the pair of magnetic pole portions of the third spoke is smaller than that of the magnetic pole portion on the other side in the circumferential direction in the pair of magnetic pole portions of the second spoke.

[0011] In the present invention, when the plurality of spokes is an even number, among the plurality of spokes, another spoke at a point-symmetric position with respect to the first spoke about the shaft is defined as the fourth spoke, and another spoke at a point-symmetric position with respect to the second spoke about the shaft is defined as the fifth spoke. It is preferable that the magnetoresistance of the magnetic pole portion on the one side in the circumferential direction in the pair of magnetic pole portions of the fourth spoke is larger than that of the magnetic pole portion on the other side in the circumferential direction. It is preferable that the magnetoresistance of the magnetic pole portion on the other side in the circumferential direction in the pair of magnetic pole portions of the fifth spoke is larger than that of the magnetic pole portion on the one side in the circumferential direction.

[0012] In the present invention, when the plurality of spokes is an odd number, among the plurality of spokes, another spoke at a point-symmetric position with respect to the slot between the first spoke and the second spoke about the shaft is defined as the 4a spoke. Another two spokes adjacent to both sides in the circumferential direction of the 4a spoke are defined as the 3a spoke and the 5a spoke. The magnetic resistances of both of the pair of magnetic pole portions included in the 4a spoke are substantially equal. In the pair of magnetic pole portions included in the 3a spoke, at least one of the magnetic pole portion on the 4a spoke side in the circumferential direction and the magnetic pole portion on the 4a spoke side in the circumferential direction in the pair of magnetic pole portions included in the 5a spoke has a smaller magnetic resistance than one of the pair of magnetic pole portions included in the 4a spoke. This is a preferable aspect.

[0013] Further, in the present invention, when the plurality of spokes are odd in number, Among the plurality of spokes, another spoke at a point-symmetrical position with respect to the slot between the 1st spoke and the 2nd spoke about the shaft is defined as the 4b spoke. Of the pair of magnetic pole portions included in the 4b spoke, the magnetic pole portion on one side or the other side in the circumferential direction has a larger magnetic resistance than the magnetic pole portion on the opposite side. In the circumferential direction, another spoke adjacent to the 4b spoke on the side of the magnetic pole portion with a smaller magnetic resistance in the pair of magnetic pole portions included in the 4b spoke is defined as the 3b spoke. It is a preferable other aspect that the magnetic pole portion on the 4b spoke side in the circumferential direction in the pair of magnetic pole portions included in the 3b spoke has a smaller magnetic resistance than the magnetic pole portion on one side in the pair of magnetic pole portions included in the 1st spoke.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

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Figure 10

Figure 11

Figure 12

Figure 13

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Figure 17

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments which are exemplary aspects of the present invention will be described with reference to the drawings. [First Embodiment] FIG. 1 is a cross-sectional view of a plane perpendicular to the axis of a motor 1 according to a first embodiment which is an example of the present invention, and FIG. 2 is a cross-sectional view of a plane including the axis. FIG. 1 is a cross-sectional view taken along line A-A in FIG. 2, and FIG. 2 is a cross-sectional view taken along line B-B in FIG. 1.

[0016] The motor 1 according to the present embodiment is a motor having a substantially square (substantially regular square) cross section, which is so-called "square motor" or "angular (DC) motor". Further, the motor 1 according to the present embodiment includes a magnet 11 having a cylindrical shape as a whole that functions as a field magnet. The magnet 11 has an integrated structure in which the outer peripheral shape in a side cross section perpendicular to the shaft 30 is a substantially regular square (square) with rounded corners, and the inner peripheral shape in the same side cross section is circular. The magnet 11 is arranged so as to surround a rotor 20 to be described later, and a cylindrical portion 12 that also serves as a frame is arranged on the outer peripheral side of the magnet 11.

[0017] The cylindrical portion 12 is a magnetic material such as a ferrous material, is arranged in contact with the outer periphery of the magnet 11, and has a substantially regular square cylindrical shape in which the inner peripheral shape in a side cross section perpendicular to the shaft 30 is substantially the same as the outer peripheral shape of the magnet 11. The stator 10 is constituted by the magnet 11 and the cylindrical portion 12. Both end openings of the cylindrical portion 12 are closed by a lid portion 50 and a bottom portion 60, respectively.

[0018] In addition, in this embodiment, when referring to the "radial direction", it represents the radial direction of a circle with the shaft 30 as the axis, and when referring to the "circumferential direction", it represents the circumferential direction of a circle with the shaft 30 as the axis. In FIG. 1, for example, the outward arrow m direction and the inward arrow m direction are the radial directions (hereinafter, may be referred to as the "radial direction mn"), and the clockwise arrow x direction and the counterclockwise arrow y direction are the circumferential directions (hereinafter, may be referred to as the "circumferential direction xy"). Also, in FIG. 1, the arrow u direction is defined as the upward direction u, and the arrow d direction is defined as the downward direction d. These upward direction u to downward direction d do not necessarily coincide with the up and down directions of the gravitational direction. The terms indicating these directions and their symbols are the same in other drawings.

[0019] Inside the magnet 11, an iron rotor core (core) 2 is disposed with a predetermined gap therebetween. The shaft 30 is fixed to the center of the rotor core 2. The rotor core 2 is a laminate such as a silicon steel sheet, and has an annular portion 2a surrounding the shaft 30 and six spokes 2b extending radially (radially) from the annular portion 2a with the shaft 30 as the axis.

[0020] At the end of each of the plurality of (six) spokes 2b of the rotor core 2 in the radial direction mn (particularly, the outward direction m), there is a pair of magnetic pole portions extending in both directions of the circumferential direction xy (hereinafter, the pair of magnetic pole portions may be collectively referred to as the "magnetic pole portion pair". In this embodiment, when the pair of magnetic pole portions are collectively referred to as the "magnetic pole portion pair", the symbol "2c" or the symbol "2c-□" (□ is an integer) is attached.). A rotor coil (coil) 3 is wound around each of the six spokes 2b. Then, the rotor core 2 and the rotor coil 3 constitute a rotor (magnetic member) 20.

[0021] Both ends of the shaft 30 are supported in a rotatable state by the first bearing 40 and the second bearing 41. The first bearing 40 is fixed to the lid portion 50, and the second bearing 41 is fixed to the bottom portion 60, and is fixed to the stator 10 via these bearings 40, 41. And the rotor 20 is made rotatable with respect to the stator 10.

[0022] A brush power supply mechanism (not shown) is provided on the shaft 30, and a drive current is supplied to the rotor coil 3 wound around the rotor core 2 described above by this brush power supply mechanism. The mechanical or electrical structure on the rotor 20 side is the same as that of a normal DC brush motor.

[0023] FIG. 3 is a cross-sectional view showing only the rotor core 2 and the shaft 30 extracted from the motor 1 according to the present embodiment. In the rotor core 2 shown in FIG. 3, the shapes of a pair of magnetic pole portions 2c-1x to 2c-6x and 2c-1y to 2c-6y of at least one (in this embodiment, all of the spokes 2b-1 to 2b-6) of a plurality of (six in this embodiment) even-numbered spokes 2b-1 to 2b-6 are different from each other.

[0024] More specifically described. First, in FIG. 3, the spoke extending upward in the u direction from the annular portion 2a is defined as the first spoke 2b-1, and the second spoke 2b-2, the third spoke 2b-3, the fourth spoke 2b-4, the fifth spoke 2b-5, and the sixth spoke 2b-6 are arranged in this order in the clockwise direction x from the first spoke 2b-1.

[0025] In the first spoke 2b-1, a groove portion 2ch extending in parallel with the axial direction of the shaft 30 is provided on the surface of the magnetic pole portion pair 2c-1 at the end in the outer direction m facing the magnet 11. As shown in FIG. 3, this groove portion 2ch is located at a position offset from the center in the circumferential direction xy to the clockwise direction x side (the second spoke 2b-2 side) in the magnetic pole portion pair 2c-1. For this reason, as shown in FIG. 3, the magnetic pole portion 2c-1x on the clockwise direction x side in the magnetic pole portion pair 2c-1 has a small cross-sectional area in the cross section, and the magnetic pole portion 2c-1y on the counterclockwise direction y side has a large cross-sectional area in the cross section.

[0026] The cross-sectional area of the cross section in the magnetic pole portions 2c-1x and 2c-1y is the cross-sectional area of the path through which the magnetic flux passes. Also, the magnetic resistance (reluctance) Rm is expressed by the following formula (1). Rm = L / μA ··· Equation (1) (In the above Equation (1), L represents the length of the magnetic circuit, A represents the cross-sectional area, and μ represents the magnetic permeability, respectively.)

[0027] That is, if the cross-sectional area μ in the denominator on the right side of Equation (1) is small, the magnetic resistance Rm becomes large (hereinafter, a large magnetic resistance is referred to as "high" and may be explicitly indicated by the symbol "H"). If the cross-sectional area μ is large, the magnetic resistance Rm becomes small (hereinafter, a small magnetic resistance Rm is referred to as "low" and may be explicitly indicated by the symbol "L").

[0028] In the magnetic pole pair 2c-1, when the position of the groove portion 2ch is deviated from the center in the circumferential direction xy, compared with the case where it is located at the center, the magnetic resistance Rm of the magnetic pole portion 2c-1x on the side where the groove portion 2ch approaches becomes large (symbol H) as shown in FIG. 3, and the magnetic resistance Rm of the magnetic pole portion 2c-1y on the side where the groove portion 2ch moves away becomes small (symbol L). Therefore, in the first spoke 2b-1, the magnetic resistance Rm of the magnetic pole portion 2c-1x on one side (clockwise direction x side) in the circumferential direction xy is larger than that of the magnetic pole portion 2-cy on the other side (counterclockwise direction y side) in the circumferential direction xy.

[0029] In the present embodiment, all of the magnetic pole pairs 2c-1 to 2c-6 included in the six spokes 2b-1 to 2b-6 have the same groove portion 2ch as the first spoke 2b-1, and the position of the groove portion 2ch is deviated from the center in the circumferential direction xy in any direction (x direction or y direction).

[0030] In the magnetic pole pair 2c-2 included in the second spoke 2b-2 adjacent to the first spoke 2b-1 on the clockwise direction x side (one side in the circumferential direction xy), the groove portion 2ch is located at a position deviated from the center in the circumferential direction xy to the counterclockwise direction y side (the first spoke 2b-1 side) as shown in FIG. 3. For this reason, as shown in FIG. 3, the magnetic pole portion 2c-2x on the clockwise direction x side in the magnetic pole pair 2c-2 has a large cross-sectional area in the cross section, and the magnetic pole portion 2c-2y on the counterclockwise direction y side has a small cross-sectional area in the cross section.

[0031] Therefore, in the magnetic pole pair 2c-2, the magnetic resistance Rm of the magnetic pole part 2c-2x, which is the side where the groove part 2ch is farther away, is smaller (symbol L) as shown in FIG. 3 than when the position of the groove part 2ch is at the center in the circumferential direction xy, and the magnetic resistance Rm of the magnetic pole part 2c-2y, which is the side where the groove part 2ch is closer, is larger (symbol H). Thus, in the second spoke 2b-2, the magnetic resistance Rm of the magnetic pole part 2c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than that of the magnetic pole part 2c-2x on one side (clockwise direction x side) in the circumferential direction xy.

[0032] Also, in the magnetic pole pair 2c-3 of the third spoke 2b-3 adjacent to the second spoke 2b-2 on the clockwise direction x side (one side in the circumferential direction xy), the groove part 2ch is located at a position offset from the center in the circumferential direction xy to the clockwise direction x side (the side opposite to the second spoke 2b-2) as shown in FIG. 3. For this reason, as shown in FIG. 3, the magnetic pole part 2c-3y on the counterclockwise direction y side in the magnetic pole pair 2c-3 has a larger cross-sectional area in the cross-section. Therefore, the cross-sectional area of the magnetic pole part 2c-3y in the cross-section is larger than that of the magnetic pole part 2c-2y on the counterclockwise direction y side in the magnetic pole pair of the second spoke 2c-2.

[0033] Therefore, in the magnetic pole pair 2c-3, the magnetic resistance Rm of the magnetic pole part 2c-3y, which is the side where the groove part 2ch is farther away, is smaller (symbol L) as shown in FIG. 3 than when the position of the groove part 2ch is at the center in the circumferential direction xy. On the other hand, as described above, the magnetic resistance Rm of the magnetic pole part 2c-2y, which is the side where the groove part 2ch is closer, in the magnetic pole pair 2c-2 is larger (symbol H).

[0034] Thus, the magnetic resistance Rm of the magnetic pole part 2c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy in the magnetic pole pair 2c-3 of the third spoke 2b-3 is smaller than that of the magnetic pole part 2c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy in the magnetic pole pair 2c-2 of the second spoke 2b-2.

[0035] Also, in the magnetic pole pair 2c-4 of the fourth spoke 2b-4 located at a point-symmetric position with respect to the shaft 30 with respect to the first spoke 2b-1, as shown in FIG. 3, the groove portion 2ch is located at a position deviated from the center in the circumferential direction xy toward the clockwise direction x side (opposite side to the third spoke 2b-3). For this reason, as shown in FIG. 3, the magnetic pole portion 2c-4y on the counterclockwise direction y side in the magnetic pole pair 2c-4 has a large cross-sectional area in the cross section, and the magnetic pole portion 2c-4x on the clockwise direction x side has a small cross-sectional area in the cross section.

[0036] Therefore, in the magnetic pole pair 2c-4, as compared with the case where the position of the groove portion 2ch is located at the center in the circumferential direction xy, the magnetic resistance Rm of the magnetic pole portion 2c-4y on the side where the groove portion 2ch is far away is small (symbol L) as shown in FIG. 3, and the magnetic resistance Rm of the magnetic pole portion 2c-4x on the side where the groove portion 2ch is close is large (symbol H).

[0037] On the other hand, in the magnetic pole pair 2c-5 of the fifth spoke 2b-5 located at a point-symmetric position with respect to the shaft 30 with respect to the second spoke 2b-2, as shown in FIG. 3, the groove portion 2ch is located at a position deviated from the center in the circumferential direction xy toward the counterclockwise direction y side (the fourth spoke 2b-4 side). For this reason, as shown in FIG. 3, the magnetic pole portion 2c-5x on the clockwise direction x side in the magnetic pole pair 2c-5 has a large cross-sectional area in the cross section, and the magnetic pole portion 2c-5y on the counterclockwise direction y side has a small cross-sectional area in the cross section.

[0038] Therefore, in the magnetic pole pair 2c-5, as compared with the case where the position of the groove portion 2ch is located at the center in the circumferential direction xy, the magnetic resistance Rm of the magnetic pole portion 2c-5x on the side where the groove portion 2ch is far away is small (symbol L) as shown in FIG. 3, and the magnetic resistance Rm of the magnetic pole portion 2c-5y on the side where the groove portion 2ch is close is large (symbol H).

[0039] Furthermore, regarding the sixth spoke 2b-6 between the first spoke 2b-1 and the fifth spoke 2b-5, as shown in FIG. 3, the groove portion 2ch is located at a position biased clockwise in the x direction (towards the first spoke 2b-1 side) from the center in the circumferential direction xy. For this reason, similarly, in the cross section, the cross-sectional area of the magnetic pole portion 2c-6x is small and the cross-sectional area of the magnetic pole portion 2c-6y is large. Therefore, in the magnetic pole pair 2c-6, compared with the case where the position of the groove portion 2ch is located at the center in the circumferential direction xy, as shown in FIG. 3, the magnetic resistance Rm of the magnetic pole portion 2c-6y, which is the side where the groove portion 2ch is farther away, is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 2c-6x, which is the side where the groove portion 2ch is closer, is large (symbol H).

[0040] In this embodiment, in all of the magnetic pole pairs 2c-1 to 2c-6 of the six spokes 2b-1 to 2b-6, the magnetic resistances Rm of the magnetic pole portions 2c-1x to 2c-6x and the magnetic pole portions 2c-1y to 2c-6y are different from each other. Therefore, the magnetic balance in the circumferential direction xy is disrupted, and an increase in cogging torque is achieved.

[0041] Hereinafter, the mechanism for increasing the cogging torque according to the configuration of this embodiment will be described. However, the mechanism in the following description is a model for explanation and includes some speculation, and thus does not guarantee the actually occurring mechanism.

[0042] FIG. 4 shows a cross-sectional view (cross-sectional drawing) of a plane perpendicular to the axis of a motor according to a conventional example. This FIG. 4 is a diagram for explaining the mechanism of generating cogging torque in the motor according to the conventional example. This conventional example motor 101 has the same configuration as the motor 1 according to the first embodiment, except that the shape of the rotor core 102 in the rotor 120 is different. Therefore, in FIG. 4 according to the conventional example, the same reference numerals are given to the members having the same configuration as those in the first embodiment.

[0043] Even in the conventional rotor core 102, in the pole part pairs 102c at the outer ends in the outer direction m of the spokes 102b, groove parts 102ch extending parallel to the axial direction of the shaft 30 are provided on the surfaces facing the magnets 11. However, in the conventional rotor core 102, as shown in FIG. 4, this groove part 102ch is located at the center in the circumferential direction xy in the pair of pole parts 102cx, 102cy that all the spokes 102b have.

[0044] For this reason, as shown in FIG. 4, the cross-sectional areas of the pole part 102cx on the clockwise direction x side and the pole part 102cy on the counterclockwise direction y side in the pair of pole parts 102cx, 102cy are equal in the cross-section. Therefore, in the spoke 102b, the magnetic resistance Rm of the pole part 102cx on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the pole part 102cy on the other side (counterclockwise direction y side) in the circumferential direction xy are substantially equal.

[0045] In FIG. 4, the forces in the direction of the cogging torque are schematically shown by white arrows, and the forces in the direction canceling the cogging torque are schematically shown by hatched arrows with slashes (the same applies to FIG. 5 described later). Since the magnetic resistances Rm of the pole part 102cx and the pole part 102cy are substantially equal, a magnetic balance in the circumferential direction is achieved. That is, since the force that becomes the cogging torque and the force in the direction canceling the cogging torque are generated in opposite directions respectively, the force that becomes the cogging torque is canceled, and in the conventional motor 101, the cogging torque becomes small.

[0046] FIG. 5 is a cross-sectional view (cross-sectional drawing) of a plane perpendicular to the axis of the motor according to the first embodiment, similar to FIG. 1, and is a diagram for explaining the generation mechanism of the cogging torque. As described above, in this embodiment, in all of the pole part pairs 2c-1 to 2c-6 that the six spokes 2b-1 to 2b-6 have, the magnetic resistance Rm of the pole parts 2c-1x to 2c-6x on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the pole parts 2c-1y to 2c-6y on the other side (counterclockwise direction y side) in the circumferential direction xy are different from each other.

[0047] Therefore, the circumferential magnetic balance is disrupted. That is, as the magnetic resistance Rm decreases and the magnetic flux becomes more permeable, the force in the direction to cancel the cogging torque (the arrow with hatching) is directed radially, so the force to cancel the cogging torque weakens, and the force causing cogging is not canceled. In the motor 1 of the present embodiment, it is presumed that the cogging torque can be increased.

[0048] In the present embodiment, an example is given in which the magnetic resistances Rm of the magnetic pole portions 2c-1x to 2c-6x and the magnetic pole portions 2c-1y to 2c-6y are different from each other in all of the magnetic pole pairs 2c-1 to 2c-6 of the six spokes 2b-1 to 2b-6. However, if the magnetic resistances Rm of a pair of magnetic pole portions in a magnetic pole pair are different from each other in at least any one of the six spokes 2b-1 to 2b-6, the circumferential magnetic balance is disrupted, so the cogging torque can be increased. However, in the present embodiment, as shown below, it is particularly preferable in that it satisfies the conditions (conditions A, B, and C) for increasing the cogging torque more.

[0049] In the present embodiment, the magnetic pole portion 2c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy of the magnetic pole pair 2c-2 of the second spoke 2b-2 has a larger magnetic resistance Rm than the magnetic pole portion 2c-2x on one side (clockwise direction x side) in the circumferential direction xy. Therefore, as shown in FIG. 3, in the slot 1S12 between the first spoke 2b-1 and the second spoke 2b-2, the magnetic pole portions 2c-1x and 2c-2y, both having a large magnetic resistance Rm (symbol H), are in a close proximity state. Thus, the locations with a large magnetic resistance Rm in the circumferential direction xy are concentrated, and the disruption of the magnetic balance is greater.

[0050] In this way, by having the state where the magnetic pole portions with a large magnetic resistance Rm are close to each other in at least one slot (condition A), the cogging torque can be increased more. The cogging torque increasing effect due to the condition A is not limited to the case of this embodiment where the number of spokes of the rotor core is six. No matter how many spokes there are, as long as this condition A is satisfied, the same effect can be achieved.

[0051] Also, in this embodiment, in the magnetic pole pair 2c-3 of the third spoke 2b-3 adjacent to one side (clockwise direction x side) in the circumferential direction xy with respect to the second spoke 2b-2, the magnetic pole part 2c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy has a smaller magnetic resistance Rm than the magnetic pole part 2c-2y on the other side (counterclockwise direction y side) in the magnetic pole pair of the second spoke 2b-2.

[0052] Therefore, as shown in FIG. 3, in the slot 1S23 between the second spoke 2b-2 and the third spoke 2b-3, the magnetic pole part 2c-2x and the magnetic pole part 2c-3y with small magnetic resistance Rm are in a close proximity state. That is, in the slot 1S23 immediately adjacent to the slot 1S12 between the first spoke 2b-1 and the second spoke 2b-2, where the magnetic pole part 2c-1x and the magnetic pole part 2c-2y with large magnetic resistance Rm are in close proximity, conversely, the magnetic pole part 2c-2x and the magnetic pole part 2c-3y with small magnetic resistance Rm are in close proximity. Thus, in the circumferential direction xy, locations with large and small magnetic resistance Rm are in close proximity, and the disruption of the magnetic balance is even greater.

[0053] In this way, in two slots 1S12 and 1S23 continuous in the circumferential direction, in one slot 1S12, magnetic pole parts with large magnetic resistance Rm (symbol H) are in close proximity to each other, and in the other slot 1S23, magnetic pole parts with small magnetic resistance Rm (symbol L) are in close proximity to each other. By making locations with large and small magnetic resistance Rm close to each other (condition B), the cogging torque can be further increased. The cogging torque increasing effect due to the condition B is not limited to the case of this embodiment where the number of spokes of the rotor core is six. No matter how many spokes there are, as long as this condition B is satisfied, the same effect can be achieved.

[0054] Furthermore, in the present embodiment, the number of spokes of the rotor core 2 is an even number, and in the pair of magnetic pole portions 2c-4 of the fourth spoke 2b-4 located at a point-symmetrical position with respect to the shaft 30 with respect to the first spoke 2b-1, the magnetic resistance Rm of the magnetic pole portion 2c-4y is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 2c-4x is large (symbol H).

[0055] On the other hand, in the pair of magnetic pole portions 2c-5 of the fifth spoke 2b-5 located at a point-symmetrical position with respect to the shaft 30 with respect to the second spoke 2b-2, the magnetic resistance Rm of the magnetic pole portion 2c-5x is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 2c-5y is large (symbol H).

[0056] Therefore, as shown in FIG. 3, in the slot 1S45 between the fourth spoke 2b-4 and the fifth spoke 2b-5, which is at a point-symmetrical position with respect to the shaft 30 with respect to the slot 1S12 between the first spoke 2b-1 and the second spoke 2b-2, the magnetic pole portions 2c-4x and 2c-5y, both having a large magnetic resistance Rm (symbol H), are in a close proximity state.

[0057] As described above, also in the slot 1S12 between the first spoke 2b-1 and the second spoke 2b-2, the magnetic pole portions 2c-1x and 2c-2y, both having a large magnetic resistance Rm (symbol H), are in a close proximity state. Therefore, slots in which magnetic pole portions having a large magnetic resistance Rm are in a close proximity state in the circumferential direction xy are located at point-symmetrical positions.

[0058] In this way, in the present embodiment, by setting the slots in which magnetic pole portions having a large magnetic resistance Rm are in a close proximity state to be located at point-symmetrical positions (condition C), the cogging torque is synergistically increased. The effect of increasing the cogging torque due to the condition C is not limited to the case of the present embodiment in which the number of spokes of the rotor core is 6, and as long as the number of spokes is an even number and this condition C is satisfied, the same effect is achieved.

[0059] [Second Embodiment] Next, a motor according to a second embodiment, which is an example of the present invention, will be described with reference to the drawings. The motor according to the second embodiment has the same configuration as the motor 1 according to the first embodiment, except that the shape of the rotor core is different. Therefore, in the present embodiment, description will be made using FIG. 6, which is a cross-sectional view showing only the rotor core (core) 22 and the shaft 30 extracted. For other configurations and the overall configuration of the motor according to the present embodiment, refer to FIGS. 1 and 2.

[0060] Also, in the present embodiment, among the six spokes 2b-1 to 2b-6 in the first embodiment, only the magnetic pole portions (reference numerals 22c-3 and 22c-6 in FIG. 6) corresponding to the magnetic pole portion pairs 2c-3 and 2c-6 of the third spoke 2b-3 and the sixth spoke 2b-6 have different shapes, and the others have the same shape or structure as the rotor core 2 in the first embodiment. Therefore, in FIG. 6 according to the present embodiment, members having the same configuration as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

[0061] In the present embodiment, in the magnetic pole portion pair 22c-3 of the third spoke 22b-3 adjacent to the second spoke 2b-2 in the clockwise direction x side (one side of the circumferential direction xy), the groove portion 2ch is located at the center of the circumferential direction xy as shown in FIG. 6. Also, in the magnetic pole portion pair 22c-6 of the sixth spoke 22b-6 located at a point-symmetrical position with respect to the shaft 30 with respect to the third spoke 22b-3, the groove portion 2ch is located at the center of the circumferential direction xy, similarly to the magnetic pole portion pair 22c-3.

[0062] That is, in the present embodiment, in the pair of magnetic pole portions 22c-3 and 22c-6 of the third spoke 22b-3 and the sixth spoke 22b-6 located at a point-symmetrical position around the shaft 30 with respect to the third spoke 22b-3, the position of the groove portion 2ch is not biased in the circumferential direction xy. Therefore, as shown in FIG. 6, the cross-sectional areas of the pair of magnetic pole portions 22c-3x and 22c-3y and the pair of magnetic pole portions 22c-6x and 22c-6y in the magnetic pole portion pairs 22c-3 and 22c-6 are substantially equal to each other in the cross-section.

[0063] Therefore, in the magnetic pole portion pair 22c-3, the magnetic resistances Rm of the magnetic pole portion 22c-3x and the magnetic pole portion 22c-6y are substantially equal to each other. This magnetic resistance Rm is smaller (lower) than in the case of symbol H and larger (higher) than in the case of symbol L. The magnetic resistance Rm of the magnetic pole portion when the position of the groove portion 2ch is not biased in the circumferential direction xy is referred to as "medium", and in FIG. 6, it is explicitly indicated by the symbol "M" (the same applies to other embodiments and drawings hereinafter).

[0064] In the present embodiment, among the six spokes 2b-1 to 22b-6, for the pair of magnetic pole portions 2c-〇 (〇 is filled with any one of the numbers 1, 2, 4, and 5. The same applies in the present embodiment hereinafter) of the four spokes 2b-〇, the magnetic resistance Rm of the magnetic pole portion 2c-〇x on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the magnetic pole portion 2c-〇y on the other side (counterclockwise direction y side) in the circumferential direction xy are different from each other. Therefore, in the present embodiment, the magnetic balance in the circumferential direction is in a state of being disrupted, and an increase in cogging torque is achieved.

[0065] Also, in the present embodiment, in the pair of magnetic pole portions 2c-2 of the second spoke 2b-2, the magnetic resistance Rm of the magnetic pole portion 2c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than that of the magnetic pole portion 2c-2x on one side (clockwise direction x side) in the circumferential direction xy.

[0066] Therefore, as shown in FIG. 6, in the slot 2S12 between the first spoke 2b-1 and the second spoke 2b-2, the magnetic pole portions 2c-1x and 2c-2y, both having a large magnetic resistance Rm (symbol H), are in a state of being close to each other. In this way, by having at least one slot in a state where magnetic pole portions having a large magnetic resistance Rm are close to each other (condition A), the cogging torque can be made larger.

[0067] Further, in the present embodiment, in the magnetic pole portion pair 22c-3 of the third spoke 22b-3 adjacent to one side (clockwise direction x side) in the circumferential direction xy with respect to the second spoke 2b-2, the magnetic resistance Rm (symbol M) of the magnetic pole portion 22c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy is smaller than the magnetic resistance Rm (symbol H) of the magnetic pole portion 2c-2y on the other side (counterclockwise direction y side) in the magnetic pole portion pair of the second spoke 2b-2.

[0068] Therefore, as shown in FIG. 6, in the slot 2S23 between the second spoke 2b-2 and the third spoke 22b-3, the magnetic pole portion 2c-2x having a small magnetic resistance Rm and the magnetic pole portion 2c-3y having a medium magnetic resistance Rm are in a state of being close to each other. That is, in the slot 2S23 immediately adjacent to the slot 2S12 between the first spoke 2b-1 and the second spoke 2b-2, where the magnetic pole portions 2c-1x and 2c-2y, both having a large magnetic resistance Rm, are close to each other, conversely, the magnetic pole portion 2c-2x having a relatively small magnetic resistance Rm and the magnetic pole portion 22c-3y are close to each other. Thus, in the circumferential direction xy, a location with a large magnetic resistance Rm and a location with a small magnetic resistance Rm are close to each other, and the degree of disruption of the magnetic balance is even greater.

[0069] In this way, in two slots 2S12 and 2S23 continuous in the circumferential direction, in one slot 2S12, magnetic pole portions both having a large magnetic resistance Rm (symbol H) are close to each other, and in the other slot 2S23, a magnetic pole portion having a small magnetic resistance Rm (symbol L) and a magnetic pole portion having a medium magnetic resistance Rm (symbol M) are close to each other (condition B), so that the cogging torque can be made even larger.

[0070] Furthermore, in the present embodiment, the number of spokes of the rotor core 22 is an even number, and in the pair of magnetic pole portions 2c-4 of the fourth spoke 2b-4 located at a point-symmetrical position about the shaft 30 with respect to the first spoke 2b-1, the magnetic resistance Rm of the magnetic pole portion 2c-4y is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 2c-4x is large (symbol H).

[0071] On the other hand, in the pair of magnetic pole portions 2c-5 of the fifth spoke 2b-5 located at a point-symmetrical position about the shaft 30 with respect to the second spoke 2b-2, the magnetic resistance Rm of the magnetic pole portion 2c-5x is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 2c-5y is large (symbol H).

[0072] Therefore, as shown in FIG. 6, in the slot 2S45 between the fourth spoke 2b-4 and the fifth spoke 2b-5, which is at a point-symmetrical position about the shaft 30 with respect to the slot 2S12 between the first spoke 2b-1 and the second spoke 2b-2, the magnetic pole portion 2c-4x and the magnetic pole portion 2c-5y, both having a large magnetic resistance Rm, are in a state of being close to each other.

[0073] As described above, also in the slot 2S12 between the first spoke 2b-1 and the second spoke 2b-2, the magnetic pole portion 2c-1x and the magnetic pole portion 2c-2y, both having a large magnetic resistance Rm, are in a state of being close to each other. Therefore, the slots in which the magnetic pole portions having a large magnetic resistance Rm are close to each other in the circumferential direction xy are located at point-symmetrical positions. In this way, in the present embodiment, due to the fact that the slots in which the magnetic pole portions having a large magnetic resistance Rm are close to each other are in a state of being located at point-symmetrical positions (condition C), the cogging torque is synergistically increased.

[0074] [Third Embodiment] Next, a motor according to a third embodiment, which is an example of the present invention, will be described with reference to the drawings. The motor according to the third embodiment has the same configuration as the motor 1 according to the first embodiment, except that the shape of the rotor core is different. Therefore, in the present embodiment, description will be made with reference to FIG. 7 which is a cross-sectional view showing only the rotor core (core) 32 and the shaft 30 extracted. For other configurations and the overall configuration of the motor according to the present embodiment, refer to FIGS. 1 and 2.

[0075] As shown in FIG. 7, the magnetic pole part pairs 32c-1 to 32c-6 are not provided with a shape such as the groove part 2ch in the first embodiment. In the present embodiment, instead of the groove part, the position where the caulking 32d is provided is offset in the circumferential direction xy. Here, the "caulking" refers to a recess provided by pressing from the thickness direction of the rotor core (axial direction of the shaft) in order to fix and integrate the rotor core made of a laminate such as a silicon steel sheet.

[0076] The caulking 32d is provided in the magnetic pole part pairs 32c-1 to 32c-6 and their vicinity in each spoke 32b-1 to 32b-6. When the caulking 32d is provided in the rotor core 32, the magnetic flux is formed so as to avoid the caulking part. Therefore, in the region where the caulking 32d is provided and its vicinity, the magnetic resistance Rm tends to increase.

[0077] In the present embodiment, as shown in FIG. 7, the position of the caulking 32d provided in the first spoke 32b-1 and the fourth spoke 32b-4 which is at a point-symmetrical position with respect to the first spoke 32b-1 about the shaft 30 is offset to the clockwise direction x side in the circumferential direction xy. The positions of the caulking 32d provided in the first spoke 32b-1 and the fourth spoke 32b-4 are point-symmetrical positions about the shaft 30.

[0078] Also, as shown in FIG. 7, the position of the caulking 32d provided in the second spoke 32b-2 and the fifth spoke 32b-5 which is at a point-symmetrical position with respect to the second spoke 32b-2 about the shaft 30 is offset to the counterclockwise direction y side in the circumferential direction xy. The positions of the caulking 32d provided in the second spoke 32b-2 and the fifth spoke 32b-5 are point-symmetrical positions about the shaft 30.

[0079] Note that, as shown in FIG. 7, the caulking 32d provided at the third spoke 32b-3 and the sixth spoke 32b-6 located at a point-symmetrical position with respect to the shaft 30 with the third spoke 32b-3 as the center is at the center in the circumferential direction xy in the third spoke 32b-3 and the sixth spoke 32b-6, and is not biased.

[0080] A line segment connecting the positions of the caulking 32d provided at the first spoke 32b-1 and the fourth spoke 32b-4 is defined as line segment L14, a line segment connecting the positions of the caulking 32d provided at the second spoke 32b-2 and the fifth spoke 32b-5 is defined as line segment L25, and a line segment connecting the positions of the caulking 32d provided at the third spoke 32b-3 and the sixth spoke 32b-6 is defined as line segment L36.

[0081] Then, the relationship between the angle α (°) formed by line segment L36 and line segment L14, the angle β (°) formed by line segment L14 and line segment L25, and the angle γ (°) formed by line segment L25 and line segment L36 is as shown in the following formula (2). β < α ≒ γ ··· Formula (2)

[0082] In the first spoke 32b-1, in the vicinity of the magnetic pole pair 32c-1, due to the influence of the caulking 32d located at a position biased toward the clockwise direction x side in the circumferential direction xy, the magnetic pole part 32c-1x on one side (clockwise direction x side) has a narrow region where magnetic flux easily penetrates, and a large magnetic resistance Rm (symbol H). Conversely, the magnetic pole part 32c-1y on the other side (counterclockwise direction y side) is not greatly affected by the caulking 32d, so it has a wide region where magnetic flux easily penetrates and a small magnetic resistance Rm (symbol L). The fourth spoke 2b-4 located at a point-symmetrical position with respect to the shaft 30 is the same as the first spoke 32b-1, where the magnetic pole part 32c-4x has a large magnetic resistance Rm (symbol H) and the magnetic pole part 32c-1y has a small magnetic resistance Rm (symbol L).

[0083] In the second spoke 32b-2, in the vicinity of the magnetic pole pair 32c-2, on the other side (counterclockwise direction y side) of the caulking 32d that is biased toward the y side in the counterclockwise direction of the circumferential direction xy, the magnetic pole part 32c-2y has a narrow region where magnetic flux easily penetrates, and a large magnetic resistance Rm (symbol H). Conversely, on one side (clockwise direction x side) of the magnetic pole part 32c-2x, since it is not greatly affected by the caulking 32d, the region where magnetic flux easily penetrates is wide, and the magnetic resistance Rm is small (symbol L). On the other hand, the fifth spoke 2b-5 at a point-symmetrical position centered on the shaft 30 is the same as the second spoke 32b-2, the magnetic pole part 32c-5y has a large magnetic resistance Rm (symbol H), and the magnetic pole part 32c-5x has a small magnetic resistance Rm (symbol L).

[0084] In the third spoke 32b-3, in the vicinity of the magnetic pole pair 32c-3, at the center of the circumferential direction xy and not being biased, the influence of the caulking 32d is substantially equal on one side (clockwise direction x side) and the other side (counterclockwise direction y side) of the circumferential direction xy. Therefore, both the magnetic pole part 32c-3x and the magnetic pole part 32c-3y have a medium magnetic resistance Rm (symbol M). The sixth spoke 32b-6 at a point-symmetrical position centered on the shaft 30 is the same as the third spoke 32b-3, and both the magnetic pole part 32c-6x and the magnetic pole part 32c-6y have a medium magnetic resistance Rm (symbol M).

[0085] In the present embodiment, among the six spokes 32b-1 to 32b-6, for the magnetic pole pairs 32c-〇 (〇 is any one of the numbers 1, 2, 4, and 5. The same applies hereinafter in this embodiment) of the four spokes 32b-〇, the magnetic resistance Rm of the magnetic pole part 32c-〇x on one side (clockwise direction x side) of the circumferential direction xy and the magnetic resistance Rm of the magnetic pole part 32c-〇y on the other side (counterclockwise direction y side) of the circumferential direction xy are different from each other. Therefore, in the present embodiment, the magnetic balance in the circumferential direction is in a state of being disrupted, and an increase in cogging torque is achieved.

[0086] Also, also in the present embodiment, in the pair of magnetic pole portions 32c-2 of the second spoke 32b-2, the magnetic pole portion 32c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy has a larger magnetic resistance Rm than the magnetic pole portion 32c-2x on one side (clockwise direction x side) in the circumferential direction xy.

[0087] Therefore, as shown in FIG. 7, in the slot 3S12 between the first spoke 32b-1 and the second spoke 32b-2, the magnetic pole portion 32c-1x and the magnetic pole portion 32c-2y, both having a large magnetic resistance Rm (symbol H), are in a state of being close to each other. In this way, by being in a state where magnetic pole portions having a large magnetic resistance Rm are close to each other in at least one slot (condition A), the cogging torque can be made larger.

[0088] Also, in the present embodiment, the magnetic resistance Rm (symbol M) of the magnetic pole portion 32c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy in the pair of magnetic pole portions 32c-3 of the third spoke 32b-3 adjacent to the second spoke 32b-2 on one side (clockwise direction x side) in the circumferential direction xy is smaller than the magnetic resistance Rm (symbol H) of the magnetic pole portion 32c-2y on the other side (counterclockwise direction y side) in the pair of magnetic pole portions 32b-2 of the second spoke 32b-2.

[0089] Therefore, as shown in FIG. 7, in the slot 3S23 between the second spoke 32b-2 and the third spoke 32b-3, the magnetic pole portion 32c-2x having a small magnetic resistance Rm and the magnetic pole portion 32c-3y having a medium magnetic resistance Rm are in a state of being close to each other. That is, in the slot 3S23 immediately adjacent to the slot 3S12 between the first spoke 32b-1 and the second spoke 32b-2, where the magnetic pole portions 32c-1x and 32c-2y, both having a large magnetic resistance Rm, are close to each other, conversely, the magnetic pole portion 32c-2x and the magnetic pole portion 32c-3y, having a relatively small magnetic resistance Rm, are close to each other. Thus, in the circumferential direction xy, a location having a large magnetic resistance Rm and a location having a small magnetic resistance Rm are close to each other, and the degree of disruption of the magnetic balance is even greater.

[0090] In this way, in the two slots 3S12 and 3S23 that are continuous in the circumferential direction, in one slot 3S12, the pole parts with a large magnetic resistance Rm (symbol H) are adjacent to each other, and in the other slot 3S23, the pole part with a small magnetic resistance Rm (symbol L) and the pole part with a medium magnetic resistance Rm (symbol M) are in a state of being close to each other (condition B), so that the cogging torque can be further increased.

[0091] Furthermore, in the present embodiment, the number of spokes of the rotor core 32 is an even number, and in the pole part pair 32c-4 of the fourth spoke 32b-4 located at a point-symmetrical position with respect to the shaft 30 with respect to the first spoke 32b-1, the magnetic resistance Rm of the pole part 32c-4y is small (symbol L), and the magnetic resistance Rm of the pole part 32c-4x is large (symbol H).

[0092] On the other hand, in the pole part pair 32c-5 of the fifth spoke 32b-5 located at a point-symmetrical position with respect to the shaft 30 with respect to the second spoke 32b-2, the magnetic resistance Rm of the pole part 32c-5x is small (symbol L), and the magnetic resistance Rm of the pole part 32c-5y is large (symbol H).

[0093] Therefore, as shown in FIG. 7, in the slot 3S45 between the fourth spoke 32b-4 and the fifth spoke 32b-5, which is at a point-symmetrical position with respect to the shaft 30 with respect to the slot 3S12 between the first spoke 32b-1 and the second spoke 32b-2, the pole part 32c-4x and the pole part 32c-5y, both of which have a large magnetic resistance Rm, are in a close state.

[0094] As described above, also in the slot 3S12 between the first spoke 32b-1 and the second spoke 32b-2, the pole part 32c-1x and the pole part 32c-2y, both of which have a large magnetic resistance Rm, are in a close state. Therefore, the slots in which the pole parts with a large magnetic resistance Rm are close to each other in the circumferential direction xy are located at point-symmetrical positions. Thus, in this embodiment, the slots in the state where the magnetic pole portions with large magnetic resistance Rm are close to each other are located at point-symmetrical positions (Condition C), so that the cogging torque is synergistically increased.

[0095] [Fourth Embodiment] Next, a motor according to a fourth embodiment, which is an example of the present invention, will be described with reference to the drawings. The motor according to the fourth embodiment has a configuration similar to that of the motor 1 according to the first embodiment, except that the shape of the rotor core is different. Therefore, in this embodiment, description will be made using FIG. 8 which is a cross-sectional view showing only the rotor core (core) 42 and the shaft 30.

[0096] However, in this embodiment, since the number of spokes of the rotor core is different from that of the motor 1 according to the first embodiment, accordingly, the magnet and the circuit structure of the control board, etc. are different from those of the motor 1 according to the first embodiment. These differences hardly appear in the appearance and are not characteristic configurations of the present invention or this embodiment. For other configurations and the overall configuration of the motor according to this embodiment, please refer to FIGS. 1 and 2. This also applies to the following embodiments.

[0097] Also, in this embodiment, for adjusting the magnetic resistance Rm of a pair of magnetic pole portions of each spoke, similar to the first embodiment and the second embodiment, the deviation in the circumferential direction xy of the groove provided on the surface facing the magnet 11 in the magnetic pole portion pair is utilized. Since the same principle is utilized, in this embodiment, duplicate explanations will be avoided, and the deviation in the circumferential direction xy of the groove will not be touched upon, and only the magnitude of the magnetic resistance Rm of the magnetic pole portion (becoming large (symbol H), becoming small (symbol L), medium (symbol M).) as a result will be discussed. This also applies to the following embodiments. Of course, any method such as deviating the position where the caulking described in the third embodiment is provided in the circumferential direction xy can be used to adjust the magnetic resistance Rm of the pair of magnetic pole portions. This also applies to the following embodiments.

[0098] In this embodiment, the rotor core 42 has an annular portion 42a surrounding the shaft 30 and five spokes 42b-1 to 42b-5 extending radially (radially) from the annular portion 42a about the shaft 30. The rotor core 42 has a pair of magnetic pole portions (magnetic pole portion pairs 42c-1 to 42c-5) extending in both circumferential directions xy at the radially outer ends mn (particularly, the outer direction m) of each of the odd number (five) of spokes 42b-1 to 42b-5. Although rotor coils (coils) are wound around each of the five spokes 42b-1 to 42b-5, illustration thereof is omitted in FIG. 8. This is the same also in FIG. 9 according to the fifth embodiment.

[0099] First, in FIG. 8, of the two spokes extending downward d from the annular portion 42a, the one on the counterclockwise direction y side is defined as the first spoke 42b-1, and the second spoke 42b-2, the third a spoke 42b-3, the fourth a spoke 42b-4, and the fifth a spoke 42b-5 are sequentially defined in the clockwise direction x from the first spoke 42b-1.

[0100] In this embodiment, in the first spoke 42b-1, the magnetic resistance Rm (symbol H) of the magnetic pole portion 42c-1x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 42c-1y on the other side (counterclockwise direction y side) in the circumferential direction xy.

[0101] Also, in the second spoke 42b-2, the magnetic resistance Rm (symbol H) of the magnetic pole portion 42c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 42c-2x on one side (clockwise direction x side) in the circumferential direction xy. Also, in the third a spoke 42b-3, the magnetic resistance Rm (symbol H) of the magnetic pole portion 42c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 42c-3x on one side (clockwise direction x side) in the circumferential direction xy.

[0102] Further, in the fifth a spoke 42b-5, the magnetic resistance Rm (symbol H) of the magnetic pole portion 42c-5x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 42c-5y on the other side (counterclockwise direction y side) in the circumferential direction xy. On the other hand, in the magnetic pole portion pair 42c-4 of the fourth a spoke 42b-4, the magnetic resistances Rm of the magnetic pole portions 42c-4x and 42c-4y on both one side (clockwise direction x side) and the other side (counterclockwise direction y side) in the circumferential direction xy are substantially equal (symbol M).

[0103] In the present embodiment, as shown in FIG. 8, among the five spokes 42b-1 to 42b-5, for the magnetic pole portion pairs 42c-〇 of the four spokes 42b-〇 (〇 is filled with any one of the numbers 1, 2, 3, and 5. The same applies hereinafter in the present embodiment), the magnetic resistance Rm of the magnetic pole portion 42c-〇x on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the magnetic pole portion 42c-〇y on the other side (counterclockwise direction y side) in the circumferential direction xy are different from each other. Therefore, in the present embodiment, the magnetic balance in the circumferential direction is in a state of being disrupted, and an increase in cogging torque is achieved.

[0104] Further, in the present embodiment, as shown in FIG. 8, in the slot 4S12 between the first spoke 42b-1 and the second spoke 42b-2, the magnetic pole portion 42c-1x and the magnetic pole portion 42c-2y, both having a large magnetic resistance Rm (symbol H), are in a state of being close to each other. In this way, by being in a state where magnetic pole portions having a large magnetic resistance Rm are close to each other in at least one slot (condition A), the cogging torque can be made larger.

[0105] In the present embodiment, since the number of spokes of the rotor core is an odd number, the condition C described in the first embodiment is not satisfied. However, in the present embodiment, as shown below, it is preferable in that it has a condition (condition D) peculiar to the case where the number of spokes is an odd number for making the cogging torque larger.

[0106] First, in this embodiment, the magnetic resistances of both magnetic pole portions 42c-4x, 42c-4y of the magnetic pole portion pair 42c-4 of the 4a spoke 42b-4, which is located point-symmetrically around the shaft 30, are approximately equal with respect to the slot 4S12 between the first spoke 42b-1 and the second spoke 42b-2 (condition D-1).

[0107] In addition, in this embodiment, the magnetic resistance Rm (symbol L) of at least one (in this embodiment, both) of the magnetic pole portion 42c-3x of the magnetic pole portion pair 42c-3 of the 3a spoke 42b-3 on the circumferential side of the 4a spoke 42b-4, and the magnetic pole portion 42c-5y of the magnetic pole portion pair 42c-5 of the 5a spoke 42b-5 on the circumferential side of the 4a spoke 42b-4, is smaller than the magnetic resistance Rm (symbol M for both 42c-4x and 42c-4y) of one of the magnetic pole portions of the magnetic pole portion pair 42c-4 of the 4a spoke 42b-4 (condition D-2).

[0108] Condition D satisfies the above conditions D-1 and D-2, and this embodiment satisfies condition D. Note that, in condition D-2, the aspect of this embodiment in which both the magnetic pole portion 42c-3x and the magnetic pole portion 42c-5y have smaller magnetic resistance Rm than the magnetic pole portion 42c-4x (≈42c-4y) is particularly preferable.

[0109] In this way, in this embodiment, by making the magnetic resistance Rm small on at least one side of the spoke located at a point symmetrical to slot 4S12, where magnetic pole portions with large magnetic resistance Rm are close to each other, the magnetic balance is further disrupted in the circumferential direction xy, and it is presumed that the cogging torque will increase further.

[0110] [Fifth embodiment] Next, a motor according to a fifth embodiment, which is an example of the present invention, will be described with reference to the drawings. The motor according to the fifth embodiment has a configuration similar to that of the motor 1 according to the first embodiment, except that the shape of the rotor core is different. Therefore, in the present embodiment, description will be made using FIG. 9 which is a cross-sectional view showing only the rotor core (core) 52 and the shaft 30 extracted.

[0111] Further, the rotor core 52 in the present embodiment is different in shape only in the magnetic pole pair (reference numeral 52c-4 in FIG. 9) corresponding to the magnetic pole pair 42c-4 of the fourth a spoke 42b-4 among the five spokes 42b-1 to 42b-5 in the fourth embodiment, and the others have the same shape or structure as the rotor core 42 in the fourth embodiment. Therefore, in FIG. 9 according to the present embodiment, members having the same configuration as those in the fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

[0112] Note that the third b spoke 52b-3 and the fifth b spoke 52b-5 in the present embodiment have the same configuration as the third a spoke 42b-3 and the fifth a spoke 42b-5 in the fourth embodiment, but for convenience of explanation, specific reference numerals (52b-3 and 52b-5) of the present embodiment are attached. The same applies to members (magnetic pole parts, magnetic pole pairs, etc.) related to the third b spoke 52b-3 and the fifth b spoke 52b-5.

[0113] In the present embodiment, in the magnetic pole pair 52c-4 of the fourth b spoke 52b-4, the magnetic resistance Rm (reference numeral H) of the magnetic pole part 52c-4x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (reference numeral L) of the magnetic pole part 52c-4y on the other side (counterclockwise direction y side) in the circumferential direction xy.

[0114] That is, in the magnetic pole part pair 42c-4 of the fourth spoke 42b-4 in the fourth embodiment, the magnetic resistances Rm of the magnetic pole parts 42c-4x and 42c-4y on both the one side (clockwise direction x side) and the other side (counterclockwise direction y side) in the circumferential direction xy are substantially equal (sign M), whereas in this embodiment, the magnetic resistances Rm of the magnetic pole parts 52c-4x and 52c-4y are different from each other.

[0115] In this embodiment, for all of the magnetic pole part pairs 42c-△ and 52c-□ of the five spokes 42b-△ (△ is filled with 1 or 2. The same applies hereinafter in this embodiment), 52b-□ (□ is filled with any number from 3 to 5. The same applies hereinafter in this embodiment), the magnetic resistance Rm of the magnetic pole part 42c-△x, 52c-□x on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the magnetic pole part 42c-△y, 52c-□y on the other side (counterclockwise direction y side) in the circumferential direction xy are different from each other. Therefore, in this embodiment, the magnetic balance in the circumferential direction is disrupted, and the point of increasing the cogging torque is the same as in the fourth embodiment.

[0116] Also, in the slot 4S12 between the first spoke 42b-1 and the second spoke 42b-2, the magnetic pole part 42c-1x and the magnetic pole part 42c-2y, both having a large magnetic resistance Rm, are in a close proximity state, and in at least one slot, the magnetic pole parts, both having a large magnetic resistance Rm, are in a close proximity state (condition A), and the point that the cogging torque can be made larger is also the same as in the fourth embodiment.

[0117] In this embodiment, since the number of spokes of the rotor core is an odd number, the condition C described in the first embodiment is not satisfied, and the condition D specific to the case where the number of spokes is an odd number, described in the fourth embodiment, is also not satisfied. However, in this embodiment, as shown below, it is preferable in that it has another condition (condition E) specific to the case where the number of spokes is an odd number for increasing the cogging torque.

[0118] First, in the present embodiment, among the magnetic pole pairs 52c-4 of the 4b spoke 52b-4 located at a point-symmetrical position around the shaft 30 with respect to the slot 4S12 between the first spoke 42b-1 and the second spoke 42b-2, the magnetic resistance Rm (symbol H) of the magnetic pole part 52c-4x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole part 52c-4y on the opposite side (condition E-1).

[0119] Also, in the present embodiment, among the magnetic pole pairs 52c-3 of the 3b spoke 52b-3 adjacent to the 4b spoke 52b-4 on the magnetic pole part 52c-y side where the magnetic resistance Rm is small in the magnetic pole pair 52c-4 of the 4b spoke 52b-4, the magnetic resistance Rm (symbol L) of the magnetic pole part 52c-3x on the 4b spoke 52b-4 side in the circumferential direction xy is smaller than the magnetic resistance Rm (symbol H) of the magnetic pole part 42c-1x on one side (clockwise direction x side) in the magnetic pole pair 42c-1 of the first spoke 42c-1 (condition E-2). Condition E is to satisfy the above conditions E-1 and E-2, and in the present embodiment, the condition E is satisfied.

[0120] Thus, in the present embodiment, in the slot between the spoke located at a position point-symmetrical to the slot 4S12 in a state where magnetic pole parts with large magnetic resistance Rm are close to each other and the spoke adjacent thereto, magnetic pole parts with small magnetic resistance Rm (in the present embodiment, the magnetic pole part 52c-3x is small (symbol L), but it may also be medium (symbol M)) are in a state of being close to each other. Therefore, it is presumed that the cogging torque further increases because the magnetic balance in the circumferential direction xy is disrupted more significantly.

[0121] [Sixth Embodiment] Next, a motor according to a sixth embodiment, which is an example of the present invention, will be described with reference to the drawings. The motor according to the sixth embodiment has a configuration similar to that of the motor 1 according to the first embodiment, except that the shape of the rotor core is different. Therefore, in the present embodiment, the description will be made using FIG. 10, which is a cross-sectional view showing only the rotor core (core) 62 and the shaft 30.

[0122] However, in the present embodiment, since the number of spokes of the rotor core is different from that of the motor 1 according to the first embodiment, accordingly, the circuit structure of the magnet and the control board, etc. is different from that of the motor 1 according to the first embodiment. In the present embodiment, the rotor core 62 has an annular portion 62a surrounding the shaft 30 and eleven spokes 62b-1 to 62b-11 extending radially (radially) from the annular portion 62a with the shaft 30 as the axis. The rotor core 52 has a pair of magnetic pole portions (magnetic pole portion pairs 62c-1 to 62c-11) extending in both circumferential directions xy at the radially outer ends mn (particularly, the outer direction m) of each of the eleven odd-numbered (eleven) spokes 62b-1 to 62b-11. Although a rotor coil (coil) is wound around each of the eleven spokes 62b-1 to 62b-11, illustration thereof is omitted in FIG. 10. The same applies to FIG. 11 according to the seventh embodiment.

[0123] First, in FIG. 10, the spoke on the counterclockwise direction y side of the two spokes extending downward d from the annular portion 62a is defined as the first spoke 62b-1, and in the clockwise direction x from the first spoke 62b-1, in order, the second spoke 62b-2, the sixth spoke 62b-6, the seventh spoke 62b-7, the eighth spoke 62b-8, the third a spoke 62b-3, the fourth a spoke 62b-4, the fifth a spoke 62b-5, the ninth spoke 62b-9, the tenth spoke 62b-10, and the eleventh spoke 62b-11.

[0124] In this embodiment, in the first spoke 62b-1, the magnetic resistance Rm (symbol H) of the magnetic pole portion 62c-1x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 62c-1y on the other side (counterclockwise direction y side) in the circumferential direction xy. Also, in the second spoke 62b-2, the magnetic resistance Rm (symbol H) of the magnetic pole portion 62c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 62c-2x on one side (clockwise direction x side) in the circumferential direction xy.

[0125] Also, in the third a spoke 62b-3, the magnetic resistance Rm (symbol H) of the magnetic pole portion 62c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 62c-3x on one side (clockwise direction x side) in the circumferential direction xy. Also, in the fifth a spoke 62b-5, the magnetic resistance Rm (symbol H) of the magnetic pole portion 62c-5x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 62c-5y on the other side (counterclockwise direction y side) in the circumferential direction xy.

[0126] On the other hand, in the magnetic pole portion pair 62c-4 of the fourth a spoke 62b-4, the magnetic resistances Rm of both the magnetic pole portions 62c-4x and 62c-4y on one side (clockwise direction x side) and the other side (counterclockwise direction y side) in the circumferential direction xy are substantially equal (symbol M).

[0127] In this embodiment, in the magnetic pole portion pairs 62c-6 to 62c-11 of the sixth to eleventh spokes 62b-6 to 62b-11 other than the above, the magnetic resistances Rm of both the magnetic pole portions 62c-6x to 62c-11x and 62c-6y to 62c-11y on one side (clockwise direction x side) and the other side (counterclockwise direction y side) in the circumferential direction xy are substantially equal (symbol M).

[0128] In this embodiment, as shown in FIG. 10, among the 11 spokes 62b-1 to 62b-11, for the magnetic pole pairs 62c-〇 (where 〇 is any one of the numbers 1, 2, 3, and 5; the same applies hereinafter) of the 4 spokes 62b-〇, the magnetic resistance Rm of the magnetic pole part 62c-〇x on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the magnetic pole part 62c-〇y on the other side (counterclockwise direction y side) in the circumferential direction xy are different from each other. Therefore, in this embodiment, the magnetic balance in the circumferential direction is disrupted, and an increase in cogging torque is achieved.

[0129] Also, in this embodiment, as shown in FIG. 10, in the slot 6S12 between the first spoke 62b-1 and the second spoke 62b-2, the magnetic pole part 62c-1x and the magnetic pole part 62c-2y, both having a large magnetic resistance Rm, are in a state of being close to each other. In this way, by having a state where magnetic pole parts with a large magnetic resistance Rm are close to each other in at least one slot (Condition A), the cogging torque can be made larger.

[0130] Furthermore, in this embodiment, it is preferable in that the number of spokes of the rotor core is 11 and it has a specific condition D peculiar to the case where the number of spokes is an odd number. That is, in this embodiment, for the slot 6S12 between the first spoke 62b-1 and the second spoke 62b-2, the magnetic resistances of both magnetic pole parts 62c-4x and 62c-4y of the magnetic pole pair 62c-4 of the fourth a spoke 42b-4 located at a point-symmetric position centered on the shaft 30 are substantially equal (Condition D-1).

[0131] In this embodiment, among the magnetic pole pairs 62c-3 of the 3a spoke 62b-3, at least one (both in this embodiment) of the magnetic pole 62c-3x on the 4a spoke 62b-4 side in the circumferential direction and the magnetic pole 62c-5y on the 4a spoke 42b-4 side in the circumferential direction of the magnetic pole pair 62c-5 of the 5a spoke 62b-5 has a magnetic resistance Rm (symbol L) smaller than the magnetic resistance Rm (both 62c-4x and 62c-4y have the symbol M) of one of the magnetic poles of the magnetic pole pair 62c-4 of the 4a spoke 62b-4 (Condition D-2).

[0132] In this embodiment, since the above Conditions D-1 and D-2 are satisfied, that is, Condition D is satisfied. In Condition D-2, the embodiment in which both the magnetic pole 62c-3x and the magnetic pole 62c-5y have a magnetic resistance Rm smaller than that of the magnetic pole 62c-4x (≈62c-4y) is particularly preferable.

[0133] In this way, in this embodiment, by making at least one side of the spoke located at a position point-symmetrical to the slot 4S12 in a state where magnetic poles with a large magnetic resistance Rm are close to each other have a small magnetic resistance Rm, the magnetic balance in the circumferential direction xy is more likely to be disrupted, so it is presumed that the cogging torque further increases.

[0134] [Seventh Embodiment] Next, a motor according to a seventh embodiment, which is an example of the present invention, will be described with reference to the drawings. The motor according to the seventh embodiment has a configuration similar to that of the motor 1 according to the first embodiment, except that the shape of the rotor core is different. Therefore, in this embodiment, the description will be made using FIG. 11, which is a cross-sectional view showing only the rotor core (core) 72 and the shaft 30.

[0135] Further, the rotor core 72 in the present embodiment is different in shape only in the pole pairs (reference numerals 72c-3 and 72c-4 in FIG. 11) corresponding to the pole pairs 62c-3 and 62c-4 of the 11 spokes 62b-1 to 62b-11 in the sixth embodiment, namely, the 3a spoke 62b-3 and the 4a spoke 62b-4, and the rest has the same shape or structure as the rotor core 62 in the sixth embodiment. Therefore, in FIG. 11 according to the present embodiment, members having the same configuration as those in the sixth embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0136] Note that the 5b spoke 72b-5 in the present embodiment has the same configuration as the 5a spoke 62b-5 in the sixth embodiment, but is denoted by a reference numeral (72b-5) specific to the present embodiment for convenience of explanation. The same applies to members (pole parts, pole pairs, etc.) related to the 5b spoke 72b-5.

[0137] In the present embodiment, in the pole pair 52c-4 of the 4b spoke 72b-4, the magnetic resistance Rm (reference numeral H) of the pole part 52c-4x on one side (clockwise direction x side) in the circumferential direction xy is larger than the magnetic resistance Rm (reference numeral L) of the pole part 52c-4y on the other side (counterclockwise direction y side) in the circumferential direction xy.

[0138] On the other hand, in the pole pair 72c-3 of the 3b spoke 72b-3, the magnetic resistances Rm of both the pole parts 72c-3x and 72c-3y on one side (clockwise direction x side) and the other side (counterclockwise direction y side) in the circumferential direction xy are substantially equal (reference numeral M).

[0139] In this embodiment, as shown in FIG. 11, among the 11 spokes 62b-〇 (a number from 1 to 11 (excluding 3 to 5) is inserted into 〇. The same applies hereinafter in this embodiment), 72b-3, 72b-□ (a 4 or 5 is inserted into □. The same applies hereinafter in this embodiment), for the 4 spokes 62b-△ (a 1 or 2 is inserted into △. The same applies hereinafter in this embodiment), 72b-□, the magnetic resistance Rm of the magnetic pole portions 62c-△x, 72c-□x on one side (clockwise direction x side) in the circumferential direction xy is different from the magnetic resistance Rm of the magnetic pole portions 62c-△y, 72c-□y on the other side (counterclockwise direction y side) in the circumferential direction xy. Therefore, in this embodiment, the magnetic balance in the circumferential direction is disrupted, and the increase in cogging torque is achieved, which is the same as in the sixth embodiment.

[0140] Also, in the slot 6S12 between the first spoke 62b-1 and the second spoke 62b-2, the magnetic pole portions 62c-1x and 62c-2y with large magnetic resistance Rm are in a close proximity state, and in at least one slot, the magnetic pole portions with large magnetic resistance Rm are in a close proximity state (Condition A), so that the cogging torque can be made larger, which is the same as in the sixth embodiment.

[0141] Furthermore, in this embodiment, it is preferable in that the number of spokes of the rotor core is 11 and it has another condition E peculiar to the case where the number of spokes is an odd number. That is, in this embodiment, for the slot 6S12 between the first spoke 62b-1 and the second spoke 62b-2, the magnetic resistance Rm (symbol H) of the magnetic pole portion 72c-4x on one side (clockwise direction x side) in the circumferential direction xy of the pair of magnetic pole portions 72c-4 of the fourth b spoke 72b-4 located at a point-symmetric position centered on the shaft 30 is larger than the magnetic resistance Rm (symbol L) of the magnetic pole portion 72c-4y on the opposite side (Condition E-1).

[0142] Further, in the present embodiment, among the magnetic pole pairs 72c-4 of the fourth b-spoke 72b-4, the magnetic resistance Rm of the magnetic pole part 72c-3x on the fourth b-spoke 72b-4 side in the circumferential direction xy of the magnetic pole pair 72-3 of the third b-spoke 72b-x adjacent to the fourth b-spoke 72b-4 on the side of the magnetic pole part 72c-4y with a small magnetic resistance Rm is smaller than the magnetic resistance Rm (symbol H) of the magnetic pole part 62c-1x on one side (clockwise direction x side) of the magnetic pole pair 62c-1 of the first spoke 62c-1 (condition E-2). Since the above conditions E-1 and E-2 are satisfied, that is, condition E is satisfied.

[0143] In this way, in the present embodiment, in the slot between the spoke located at a position point-symmetrical to the slot 6S12 in a state where magnetic pole parts with a large magnetic resistance Rm are close to each other and the spoke adjacent thereto, magnetic pole parts with a small magnetic resistance Rm (even if the magnetic pole part 72c-3x is medium (symbol M) as in the present embodiment) are in a state of being close to each other. Therefore, since the magnetic balance in the circumferential direction xy is more likely to be disrupted, it is presumed that the cogging torque further increases.

[0144] [Eighth Embodiment] Next, a motor according to an eighth embodiment, which is an example of the present invention, will be described with reference to the drawings. FIG. 12 is a cross-sectional view of a motor 8 according to the eighth embodiment in a plane perpendicular to the axis, and FIG. 13 is a cross-sectional view of a plane including the axis. FIG. 12 is a C-C cross-sectional view in FIG. 13, and FIG. 13 is a D-D cross-sectional view in FIG. 12.

[0145] In the motor 8 according to the eighth embodiment, a member having the same configuration as the rotor (rotor core 2 and rotor coil 3) of the motor 1 according to the first embodiment is used as the stator (reference numeral 80 in the present embodiment). That is, while the motor 1 is an inner rotor type motor, the motor 8 is an outer rotor type motor.

[0146] Although there are various differences such as the shape of the magnet and the configuration of the shaft support, the motor 8 according to the present embodiment has a configuration similar to that of the motor 1 according to the first embodiment. Therefore, in FIGS. 12 and 13 according to the present embodiment, members having the same configuration as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0147] In the present embodiment, the rotor 81 has a magnet 81a and a rotor hub 81b. The rotor hub 81b is arranged coaxially with the shaft 30 and is cup-shaped as a whole, and includes a cylindrical portion 81c to which the magnet 81a is attached to the inner peripheral surface, a disk portion 81e continuous with the cylindrical portion 81c on one axial direction (left direction in FIG. 13) side of the shaft 30, and a cylindrical connection portion 81d continuous with the disk portion 81e.

[0148] The rotor hub 81b is a magnetic body such as an iron material, and the shaft 30 inserted into the connection portion 81d is fixed to the connection portion 81d, and the two are integrated. On the inner peripheral surface of the cylindrical portion 81c, six magnets 81a are arranged so as to surround a stator core 82 described later. The magnets 81a are arranged such that the N poles and the S poles face the stator core 82 alternately in the circumferential direction.

[0149] Inside the magnet 81a, a stator core 82 which is a part of the iron stator 80 is arranged with a predetermined gap therebetween. In the present embodiment, the stator 80 includes an annular portion 82a arranged coaxially with and surrounding the shaft 30, a stator core 82 including six spokes 82b extending radially (radially) from the annular portion 82a, a stator hub 82e extending radially (radially) and expanding in diameter on the other axial direction (right direction in FIG. 13) side of the shaft 30 from the annular portion 82a, and stator coils (coils) 83 wound around the six spokes 82b of the stator core 82, respectively.

[0150] In the annular portion 82a, in the axial direction of the shaft 30, a spoke 82b and a stator hub 84 are connected in order from one direction to the other direction (from the left direction to the right direction in FIG. 13), and the annular portion 82a further extends (this extended portion is referred to as an "annular extension portion" and is denoted by reference numeral 82e). A disk-shaped bottom portion 61 is attached between the annular extension portion 82e and a part of the stator hub 84. The bottom portion 61 and the stator 80 constitute a fixing portion.

[0151] The shaft 30 is supported in a rotatable state by a first bearing 40 and a second bearing 41 on one side (the left side in FIG. 13) and the other side (the right side in FIG. 13) of the center in the axial direction thereof. The first bearing 40 and the second bearing 41 are respectively fixed to the inner peripheral surface of the annular portion 82a and are fixed to the stator 80 via these bearings 40 and 41. That is, the shaft 30 is rotatably fixed to the stator 80. Therefore, the rotating portion composed of the shaft 30 and the rotor 81 is in a rotatable state with respect to the fixing portion composed of the stator 80 and the bottom portion 61.

[0152] A power supply mechanism (not shown) is arranged in the stator 80, and a predetermined drive current is supplied to the stator coil 83 wound around the stator core 82 by this power supply mechanism. The mechanical or electrical structure on the stator 80 side is the same as that of a general brushless DC motor.

[0153] FIG. 14 is a cross-sectional view showing only the stator core 82 extracted from the motor 80 according to the present embodiment. As can be seen by comparing with FIG. 3, the shape of the stator core 82 in the present embodiment is the same as that of the rotor core 2 in the first embodiment. The stator coil 83 (see FIG. 13) in the present embodiment and the rotor coil 3 (see FIG. 1) in the first embodiment also have the same configuration, and the stator 80 in the present embodiment and the rotor 20 in the first embodiment can be said to be the same when viewed as individual components.

[0154] That is, the stator 80 in the present embodiment can be regarded as the same magnetic member as the rotor 20 in the first embodiment. Therefore, although the roles of the stator 80 and the rotor 20 in the motors (8, 9) are different, they exhibit equivalent magnetic characteristics. Thus, the motor 8 according to the present embodiment can enjoy the effect of increasing the cogging torque, similar to the motor 1 according to the first embodiment.

[0155] In the present embodiment, all of the magnetic pole pairs 82c-1 to 82c-6 of the six spokes 82b-1 to 82b-6 have different magnetic resistances Rm between the magnetic pole part 82c-〇x (where 〇 is any number from 1 to 6. The same applies hereinafter in the present embodiment) on one side (clockwise direction x side) in the circumferential direction xy and the magnetic pole part 82c-〇y on the other side (counterclockwise direction y side) in the circumferential direction xy. Therefore, in the present embodiment, the magnetic balance in the circumferential direction is disrupted, and an increase in the cogging torque is achieved.

[0156] Also, in the present embodiment, in the magnetic pole pair 82c-2 of the second spoke 82b-2, the magnetic pole part 82c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy has a larger magnetic resistance Rm than the magnetic pole part 82c-2x on one side (clockwise direction x side) in the circumferential direction xy.

[0157] Therefore, as shown in FIG. 14, in the slot 8S12 between the first spoke 82b-1 and the second spoke 82b-2, the magnetic pole parts 82c-1x and 82c-2y, both having a large magnetic resistance Rm, are in a close proximity state. In this way, by having a state where magnetic pole parts with a large magnetic resistance Rm are close to each other in at least one slot (condition A), the cogging torque can be made larger.

[0158] In addition, in the present embodiment, in the magnetic pole pair 82c-3 of the third spoke 82b-3 adjacent to one side (clockwise direction x side) in the circumferential direction xy with respect to the second spoke 82b-2, the magnetic resistance Rm (symbol M) of the magnetic pole portion 82c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy is smaller than the magnetic resistance Rm (symbol H) of the magnetic pole portion 82c-2y on the other side (counterclockwise direction y side) in the magnetic pole pair of the second spoke 82b-2.

[0159] Therefore, as shown in FIG. 14, in the slot 8S23 between the second spoke 82b-2 and the third spoke 82b-3, the magnetic pole portions 82c-2x and 2c-3y with small magnetic resistance Rm are in a state of being close to each other. That is, in the slot 8S23 immediately adjacent to the slot 8S12 between the first spoke 82b-1 and the second spoke 82b-2, where the magnetic pole portions 82c-1x and 82c-2y with large magnetic resistance Rm are close to each other, conversely, the magnetic pole portions 82c-2x and 82c-3y with small magnetic resistance Rm are close to each other. Thus, in the circumferential direction xy, locations with large and small magnetic resistance Rm are close to each other, and the imbalance of the magnetic balance becomes even greater.

[0160] In this way, in two slots 8S12 and 8S23 continuous in the circumferential direction, in one slot 8S12, magnetic pole portions with large magnetic resistance Rm (symbol H) are close to each other, and in the other slot 8S23, magnetic pole portions with small magnetic resistance Rm (symbol L) are close to each other. By bringing locations with large and small magnetic resistance Rm close to each other (condition B), the cogging torque can be made even larger.

[0161] Furthermore, in the present embodiment, the number of spokes of the stator core 82 is an even number, and in the magnetic pole pair 82c-4 of the fourth spoke 82b-4 located at a point-symmetric position with respect to the shaft 30 (see FIG. 12) around the first spoke 82b-1, the magnetic resistance Rm of the magnetic pole portion 82c-4y is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 82c-4x is large (symbol H).

[0162] On the other hand, in the magnetic pole pair 82c-5 of the fifth spoke 82b-5 located at a point-symmetric position with respect to the second spoke 82b-2 about the shaft 30 (see FIG. 12), the magnetic resistance Rm of the magnetic pole portion 82c-5x is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 82c-5y is large (symbol H).

[0163] Therefore, as shown in FIG. 14, in the slot 8S45 between the fourth spoke 82b-4 and the fifth spoke 82b-5, which is at a point-symmetric position with respect to the shaft 30 (see FIG. 12) with respect to the slot 8S12 between the first spoke 82b-1 and the second spoke 82b-2, the magnetic pole portion 82c-4x and the magnetic pole portion 82c-5y, both of which have a large magnetic resistance Rm, are in a close proximity state.

[0164] As described above, also in the slot 8S12 between the first spoke 82b-1 and the second spoke 82b-2, the magnetic pole portion 82c-1x and the magnetic pole portion 82c-2y, both of which have a large magnetic resistance Rm, are in a close proximity state. Therefore, slots in which magnetic pole portions having a large magnetic resistance Rm are in a close proximity state in the circumferential direction xy are located at point-symmetric positions. In this way, in the present embodiment, the cogging torque is synergistically increased because the slots in which the magnetic pole portions having a large magnetic resistance Rm are in a close proximity state are located at point-symmetric positions (condition C).

[0165] Note that, in the present embodiment, as an example of the shape of the stator core 82, the shape is the same as that of the rotor core 2 in the first embodiment, but it is not limited thereto. For example, the stator core 82 may be replaced with a shape similar to any of the rotor cores exemplified in the second to seventh embodiments, and the effects according to the present invention can be achieved in any shape.

[0166] [Embodiment 9] Next, a motor according to a ninth embodiment, which is an example of the present invention, will be described with reference to the drawings. FIG. 15 is a cross-sectional view of the motor 9 according to the ninth embodiment in a plane perpendicular to the axis.

[0167] The motor 9 according to the ninth embodiment is an inner-rotor type motor, similar to the motor 1 according to the first embodiment. However, the configurations of the rotor (the rotor core 2 and the rotor coil 3 in the first embodiment) and the stator (the stator 10 in the first embodiment) are significantly different from those of the motor 1.

[0168] That is, in the motor 1 according to the first embodiment, a magnetic member in which the coil 3 is wound around a plurality (six) of spokes 2b with the tip magnetic pole pair 2c facing outward and arranged radially is used as the rotor. In contrast, in the motor 9 according to the present embodiment, a magnetic member in which the stator coil (coil) 93 is wound around a plurality (six) of spokes 92b with the tip magnetic pole pair 92c (facing the central shaft 30, in the opposite direction to the motor 1) arranged radially is used as the stator 90 here, which is different.

[0169] With this difference in the configuration of the magnetic member, in the present embodiment, the configuration of the rotor 91 is also significantly different from that of the rotor in the first embodiment and, of course, from that of the stator 10. That is, the rotor 91 in the present embodiment is a cylindrical member with the shaft 30 inserted and fixed in the inner hole, and the outer surface is magnetized so that the S pole and the N pole are alternately arranged in the circumferential direction to form a magnet. Note that as the rotor 91, magnets may be embedded in the outer surface of the cylindrical member so that the S pole and the N pole are alternately arranged in the same way.

[0170] Outside the rotor 91 whose outer peripheral surface is a magnet, a stator 92 having spokes 2b with the tip magnetic pole pair 2c facing each other through a predetermined gap is arranged. The stator 90 includes a stator core 92 having six spokes 2b and stator coils 93 wound around each of the stator cores 92.

[0171] The stator core 92 is a laminate such as a silicon steel sheet, and has an annular portion 92a surrounding the shaft 30 and the aforementioned spokes 2b extending (radially) from the inner peripheral surface of the annular portion 92a toward the central axis side in the radial direction (shaft 30 side). Note that a cylindrical case 94 is disposed further outside the annular portion 92a of the stator core 92, and the stator 90 is fixed thereto.

[0172] The stator core 92 has a pair of magnetic pole portions extending in both circumferential directions xy at the end portions of each of a plurality (six) of the spokes 2b in the radial direction mn (particularly, the inner direction n). (In some cases, the pair of magnetic pole portions may be collectively referred to as a "magnetic pole portion pair". In the present embodiment, when the pair of magnetic pole portions are collectively referred to as a "magnetic pole portion pair", the symbol "92c" or the symbol "92c-□" (□ is an integer) is attached.)

[0173] Note that, in the present embodiment, a cross-sectional view of the plane including the axis of the motor 9 is omitted, but the shaft 30 has the inner rings of two bearings (not shown) fixed in the axial direction of the shaft 30, and the outer rings of the bearings are fixed to the case 94, so that the rotor 91 is rotatable with respect to the stator 90.

[0174] FIG. 16 is a cross-sectional view showing only the rotor core 92 extracted from the motor 9 according to the present embodiment. In the rotor core 92 shown in FIG. 16, the shapes of a pair of magnetic pole portions 92c-1x to 92c-6x and 92c-1y to 92c-6y included in at least one (in the present embodiment, all) of a plurality (six in the present embodiment) of even-numbered spokes 92b-1 to 92b-6 are different from each other.

[0175] More specifically, an explanation will be given. First, in FIG. 16, the spoke extending downward d from the annular portion 92a is defined as the first spoke 92b-1, and the second spoke 92b-2, the third spoke 92b-3, the fourth spoke 92b-4, the fifth spoke 92b-5, and the sixth spoke 92b-6 are sequentially arranged in the clockwise direction x from the first spoke 92b-1.

[0176] FIG. 17 shows an enlarged view of the periphery of the tip of each spoke 92b (the periphery of the magnetic pole portion 92c) in the motor according to the ninth embodiment. In the first spoke 92b-1, a groove portion 92ch extending parallel to the axial direction of the shaft 30 is provided on the surface of the magnetic pole portion pair 92c-1 at the end in the outer direction n facing the magnet of the rotor 91 (see FIG. 15).

[0177] As shown in FIG. 17, this groove portion 92ch is located at a position deviated from the center in the circumferential direction xy toward the clockwise direction x side (the second spoke 92b-2 side) in the magnetic pole portion pair 92c-1. For this reason, as shown in FIG. 17, the magnetic pole portion 92c-1x on the clockwise direction x side in the magnetic pole portion pair 92c-1 has a small cross-sectional area in the cross section, and the magnetic pole portion 92c-1y on the counterclockwise direction y side has a large cross-sectional area in the cross section.

[0178] Therefore, in the magnetic pole portion pair 92c-1, when the position of the groove portion 92ch is deviated from the center in the circumferential direction xy, the magnetic resistance Rm of the magnetic pole portion 92c-1x on the side where the groove portion 92ch is closer becomes larger (symbol H) as shown in FIG. 17 compared to the case where it is located at the center, and the magnetic resistance Rm of the magnetic pole portion 92c-1y on the side where the groove portion 92ch is farther away becomes smaller (symbol L). Thus, in the first spoke 92b-1, the magnetic resistance Rm of the magnetic pole portion 92c-1x on one side (clockwise direction x side) in the circumferential direction xy is larger than that of the magnetic pole portion 92-cy on the other side (counterclockwise direction y side) in the circumferential direction xy.

[0179] In this embodiment, all of the magnetic pole portion pairs 92c-1 to 92c-6 of the six spokes 92b-1 to 92b-6 have the same groove portion 92ch as the first spoke 92b-1, and the position of the groove portion 92ch is deviated from the center in the circumferential direction xy in any direction (x direction or y direction).

[0180] In the pair of magnetic pole portions 92c-2 of the second spoke 92b-2 adjacent to the first spoke 92b-1 in the clockwise direction x side (one side of the circumferential direction xy), as shown in FIG. 17, the groove portion 92ch is located at a position deviated from the center of the circumferential direction xy toward the counterclockwise direction y side (the first spoke 92b-1 side). Therefore, as shown in FIG. 17, the magnetic pole portion 92c-2x on the clockwise direction x side in the pair of magnetic pole portions 92c-2 has a large cross-sectional area in the cross section, and the magnetic pole portion 92c-2y on the counterclockwise direction y side has a small cross-sectional area in the cross section.

[0181] Therefore, in the pair of magnetic pole portions 92c-2, compared with the case where the position of the groove portion 92ch is located at the center of the circumferential direction xy, the magnetic resistance Rm of the magnetic pole portion 92c-2x on the side where the groove portion 92ch is far away is small (symbol L) as shown in FIG. 17, and the magnetic resistance Rm of the magnetic pole portion 92c-2y on the side where the groove portion 92ch is close is large (symbol H). Thus, in the second spoke 92b-2, the magnetic resistance Rm of the magnetic pole portion 92c-2y on the other side (counterclockwise direction y side) of the circumferential direction xy is larger than that of the magnetic pole portion 92c-2x on one side (clockwise direction x side) of the circumferential direction xy.

[0182] Although there is a difference in whether the directions of the pairs of magnetic pole portions 92c-1 and 92c-2 in the first spoke 92b-1 and the second spoke 92b-2 face the center axis side (shaft 30 side) or the outer side (outer circumferential direction) as in the pairs of magnetic pole portions 2c-1 and 2c-2 in the first spoke 2b-1 and the second spoke 2b-2 in the first embodiment, in the circumferential direction, the order of the magnitudes of the cross-sectional areas of the magnetic pole portions 92c in the cross section, in other words, the order of the magnitudes of the magnetic resistances Rm of the magnetic pole portions 92c, is the same.

[0183] That is, in the clockwise direction x, the magnetic resistances Rm of the magnetic pole portions 92c-1y, 92c-1x, 92c-2y, and 92c-2x are the same as those of the magnetic pole portions 2c-1y, 2c-1x, 2c-2y, and 2c-2x in the first embodiment. When represented by symbols in this order as they are, both are L, H, H, and L. The same applies to the remaining magnetic pole portions 92c-3y to 92c-6y and the magnetic pole portions 92c-3x to 92c-6x, which are the same as the magnetic pole portions 2c-3y to 2c-6y and the magnetic pole portions 2c-3x to 92c-6x in the first embodiment.

[0184] Therefore, also in this embodiment, the same actions and effects regarding cogging torque as in the first embodiment are achieved. That is, in this embodiment, for all of the magnetic pole pairs 92c-1 to 92c-6 of the six spokes 92b-1 to 92b-6, the magnetic resistance Rm of the magnetic pole portions 92c-1x to 92c-6x on one side (clockwise direction x side) in the circumferential direction xy and the magnetic resistance Rm of the magnetic pole portions 92c-1y to 92c-6y on the other side (counterclockwise direction y side) in the circumferential direction xy are different from each other. Therefore, in this embodiment, the magnetic balance in the circumferential direction is in a disrupted state, and an increase in cogging torque is achieved.

[0185] Also, in this embodiment, in the magnetic pole pair 92c-2 of the second spoke 92b-2, the magnetic resistance Rm of the magnetic pole portion 92c-2y on the other side (counterclockwise direction y side) in the circumferential direction xy is larger than that of the magnetic pole portion 92c-2x on one side (clockwise direction x side) in the circumferential direction xy.

[0186] Therefore, as shown in Fig. 17, in the slot 9S12 between the first spoke 92b-1 and the second spoke 92b-2, the magnetic pole portions 32c-1x and 32c-2y, both of which have a large magnetic resistance Rm, are in a proximate state. In this way, by having a state where magnetic pole portions with a large magnetic resistance Rm (symbol H) are proximate to each other in at least one slot (condition A), the cogging torque can be made larger.

[0187] In addition, in the present embodiment, in the magnetic pole pair 92c-3 of the third spoke 92b-3 adjacent to one side (clockwise direction x side) in the circumferential direction xy with respect to the second spoke 92b-2, the magnetic resistance Rm (symbol L) of the magnetic pole portion 92c-3y on the other side (counterclockwise direction y side) in the circumferential direction xy is smaller than the magnetic resistance Rm of the magnetic pole portion 92c-2y on the other side (counterclockwise direction y side) in the magnetic pole pair 92b-2 of the second spoke 92b-2.

[0188] Therefore, as shown in FIG. 17, in the slot 9S23 between the second spoke 92b-2 and the third spoke 92b-3, the magnetic pole portions 92c-2x and 92c-3y with small magnetic resistance Rm are in a close proximity state. That is, in the slot 3S23 immediately adjacent to the slot 3S12 between the first spoke 92b-1 and the second spoke 92b-2, where the magnetic pole portions 92c-1x and 92c-2y with large magnetic resistance Rm are in close proximity, conversely, the magnetic pole portions 92c-2x and 92c-3y with small magnetic resistance Rm are in close proximity. Thus, in the circumferential direction xy, locations with large and small magnetic resistance Rm are in close proximity, and the imbalance of the magnetic balance becomes even greater.

[0189] In this way, in two slots 9S12 and 9S23 that are continuous in the circumferential direction, in one slot 9S12, magnetic pole portions with large magnetic resistance Rm (symbol H) are in close proximity to each other, and in the other slot 9S23, magnetic pole portions with small magnetic resistance Rm (symbol L) are in close proximity to each other (condition B), thereby enabling the cogging torque to be made even larger.

[0190] Furthermore, in the present embodiment, the number of spokes of the stator core 92 is an even number, and in the magnetic pole pair 92c-4 of the fourth spoke 92b-4 located at a point-symmetric position centered on the shaft 30 (see FIG. 15) with respect to the first spoke 92b-1, the magnetic resistance Rm of the magnetic pole portion 92c-4y is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 92c-4x is large (symbol H).

[0191] On the other hand, in the pair of magnetic pole portions 92c-5 of the fifth spoke 92b-5 located at a point-symmetrical position with respect to the second spoke 92b-2 about the shaft 30 (see FIG. 15), the magnetic resistance Rm of the magnetic pole portion 92c-5x is small (symbol L), and the magnetic resistance Rm of the magnetic pole portion 92c-5y is large (symbol H).

[0192] Therefore, as shown in FIG. 7, in the slot 9S45 between the fourth spoke 92b-4 and the fifth spoke 92b-5, which is at a point-symmetrical position with respect to the shaft 30 (see FIG. 15) with respect to the slot 9S12 between the first spoke 92b-1 and the second spoke 92b-2, the magnetic pole portions 92c-4x and 92c-5y, both of which have a large magnetic resistance Rm (symbol H), are in a close proximity state.

[0193] As described above, in the slot 9S12 between the first spoke 92b-1 and the second spoke 92b-2, the magnetic pole portions 92c-1x and 92c-2y, both of which have a large magnetic resistance Rm, are also in a close proximity state. Therefore, slots in which magnetic pole portions having a large magnetic resistance Rm are in a close proximity state in the circumferential direction xy are located at point-symmetrical positions. In this way, in the present embodiment, due to the fact that slots in which magnetic pole portions having a large magnetic resistance Rm are in a close proximity state are located at point-symmetrical positions (condition C), the cogging torque is synergistically increased.

[0194] In the present embodiment, the stator 90 as a magnetic member characteristic of the present invention is fixed, and by supplying a predetermined current to the stator coil 93 provided in the stator 90, the inner rotor type motor 9 that rotates the shaft 30 together with the rotor 91 located inside the stator 90 has been described as an example. However, similar to the relationship between the eighth embodiment and the first embodiment, even if the functions of the rotor and the stator are interchanged, the actions and effects according to the present invention can be achieved.

[0195] That is, in the present embodiment, by rotatably supporting a magnetic member having the same shape and the same configuration as the stator 80 with respect to the case 94, this is used as a rotor, and on the other hand, by separating the member corresponding to the rotor 81 from the shaft 30 and fixing it to the case 94, this is used as a stator. Even in an outer rotor type motor, the actions and effects according to the present invention can be realized.

[0196] As described above, the motor of the present invention has been described with reference to preferred embodiments. However, the motor of the present invention is not limited to the configuration of the above embodiments. For example, in the above embodiments, the number of spokes is 5, 6, and 11 are described as examples. However, the number of spokes is not particularly limited, and any plurality of spokes may be used. Also, regarding the condition C peculiar to an even number of spokes, the number of spokes is not limited to 6, and may be 4, 8 or more. Further, regarding the condition D and condition E peculiar to an odd number of spokes, the number of spokes is not limited to 5 or 11, and may be 3, 7, or 9, or 13 or more.

[0197] Also, in the above embodiment, as a method of adjusting the magnetic resistance of the magnetic pole portions of each spoke, two methods are mentioned: a method of shifting the position of the groove in the magnetic pole portion pair and a method of shifting the caulking position. However, the present invention is not limited to this. For example, any method such as a method of changing the cross-sectional area of the magnetic path in the magnetic pole portion by other methods may be used.

[0198] Also, as the magnetic resistance Rm of the magnetic pole portions of each spoke, they may be exactly equal in each of large (symbol H), medium (symbol M), and small (symbol L), or there may be a difference or error of approximately equal degree, or a clear difference may be given to the magnitude of each magnetic resistance Rm.

[0199] In addition, those skilled in the art can appropriately modify the motor of the present invention according to conventionally known knowledge. As long as the configuration of the present invention is still included by such modifications, of course, it is included in the scope of the present invention.

Explanation of reference numerals

[0200] 1…Motor, 2…Rotor core (core), 2a…Annular part, 2b…Spoke, 2b-1…First spoke, 2b-2…Second spoke, 2b-3…Third spoke, 2b-4…Fourth spoke, 2b-5…Fifth spoke, 2b-6…Sixth spoke, 2c, 2c-1~2c-6…Pair of magnetic pole parts (a pair of magnetic pole parts), 2c-1x~2c-6x, 2c-1y~2c-6y…Magnetic pole parts, 2ch…Groove part, 3…Rotor coil (coil), 8…Motor, 9…Motor, 10…Stator, 11…Magnet, 12…Cylindrical part, 20…Rotor (magnetic member), 22 Rotor core (core), 22b-3…Third spoke, 22b-6…Sixth spoke, 22c-3, 2c-6…Pair of magnetic pole parts (a pair of magnetic pole parts), 22c-3x, 22c-6x, 22c-3y, 22c-6y…Magnetic pole parts, 30…Shaft, 32…Rotor core (core), 32a…Annular part, 32b-1…First spoke, 32b-2…Second spoke, 32b-3…Third spoke, 32b-4…Fourth spoke, 32b-5…Fifth spoke, 32b-6…Sixth spoke, 32c-1~32c-6…Pair of magnetic pole parts (a pair of magnetic pole parts), 32c-1x~32c-6x, 32c-1y~32c-6y…Magnetic pole parts, 32d…Crimping, 40…First bearing, 41…Second bearing, 42…Rotor core (core), 42a…Annular part, 42b-1…First spoke 42b-2…Second spoke, 42b-3…Third spoke, 42b-4…Fourth spoke, 42b-5…Fifth spoke, 42c-1~42c-5…Pair of magnetic pole parts (a pair of magnetic pole parts), 42c-1x~42c-5x, 42c-1y~42c-5y…Magnetic pole parts, 50…Cover part, 52…Rotor core (core), 52b-3…Third spoke, 52b-4…Fourth spoke, 52b-5…Fifth spoke, 52c-3~52c-5…Pair of magnetic pole parts (a pair of magnetic pole parts), 52c-3x~52c-5x, 52c-3y~52c-5y…Magnetic pole parts, 60…Bottom part, 61…Bottom part, 62…Rotor core (core), 62a…Annular part, 62b-1…First spoke 62b-2…Second spoke, 62b-3…Third spoke, 62b-4…Fourth spoke, 62b-5…Fifth spoke, 62b-6…Sixth spoke 62b-7…Seventh spoke, 62b-8…Eighth spoke, 62b-9…Ninth spoke, 62b-10…Tenth spoke, 62b-11…Eleventh spoke, 62c-1~62c-11…Pair of magnetic pole parts (a pair of magnetic pole parts), 62c-1x~62c-11x,62c-1y~62c-11y…Magnetic pole part, 72…Rotor core (core), 72b-3…Third spoke, 72b-4…Fourth spoke, 72b-5…Fifth spoke, 72c-3~72c-5…Pair of magnetic pole parts (a pair of magnetic pole parts), 72c-3x~72c-5x, 72c-3y~72c-5y…Magnetic pole part, 80…Stator (magnetic member), 81…Rotor, 81a…Magnet, 81b…Cylindrical part, 81c…Rotor hub, 81d…Connection part, 82…Stator core (core), 82a…Annular part, 82b…Spoke, 82c-1~82c-6…Pair of magnetic pole parts (a pair of magnetic pole parts), 82c-1x~82c-6x, 82c-1y~82c-6y…Magnetic pole part, 82e…Stator hub, 82f…Annular extension part, 83…Stator coil (coil), 90…Stator (magnetic member), 91…Rotor (magnet), 92…Stator core (core), 92a…Annular part, 92b…Spoke, 92c, 92c-1~92c-6…Pair of magnetic pole parts (a pair of magnetic pole parts), 92c-1x~92c-6x, 92c-1y~92c-6y…Magnetic pole part, 93…Stator coil (coil), 94…Case, 101…Motor, 102…Rotor core, 102b…Spoke, 102c…Pair of magnetic pole parts, 102ch…Groove part, 102cx, 102cy…Magnetic pole part,

Claims

1. A shaft, a magnetic member having a plurality of spokes extending radially from the shaft, a magnet arranged in an annular shape, and coils wound around each of the plurality of spokes, comprising: in the radial direction, one of the magnetic member and the magnet is arranged inside the other, in the radial direction, each end of the plurality of spokes faces the magnet, each end of the plurality of spokes has a pair of magnetic pole portions extending in opposite directions in the circumferential direction and a surface facing the magnet, the plurality of spokes include, in the circumferential direction, a first spoke, a second spoke on one magnetic pole portion side of the pair of magnetic pole portions of the first spoke, and a third spoke on the other magnetic pole portion side of the first spoke, of the pair of magnetic pole portions of the first spoke, the magnetic resistance of one magnetic pole portion is greater than that of the other magnetic pole portion, a groove portion is formed on the surface of the end of the first spoke on the second spoke side with respect to the first spoke, of the pair of magnetic pole portions of the second spoke, the magnetic resistance of the other magnetic pole portion is greater than that of one magnetic pole portion, a groove portion is formed on the surface of the end of the second spoke on the first spoke side with respect to the second spoke, the magnetic resistances of the pair of magnetic pole portions of the third spoke are substantially equal, a groove portion is formed at the center of the third spoke in the circumferential direction on the surface of the end of the third spoke, the plurality of spokes are even in number, among the plurality of spokes, another spoke at a point-symmetric position with respect to the first spoke about the shaft is defined as a fourth spoke, and another spoke at a point-symmetric position with respect to the second spoke about the shaft is defined as a fifth spoke, of the pair of magnetic pole portions of the fourth spoke, one magnetic pole portion has a greater magnetic resistance than the other magnetic pole portion, of the pair of magnetic pole portions of the fifth spoke, the other magnetic pole portion has a greater magnetic resistance than the one magnetic pole portion, a motor.

2. A shaft, a magnetic member having a plurality of spokes extending radially from the shaft, a magnet arranged in an annular shape, and coils wound around each of the plurality of spokes, comprising: in the radial direction, one of the magnetic member and the magnet is arranged inside the other, In the radial direction, each end of the plurality of spokes faces the magnet. Each end of the plurality of spokes has a pair of magnetic pole portions extending in opposite directions in the circumferential direction and a surface facing the magnet. The plurality of spokes include, in the circumferential direction, a first spoke, a second spoke on one magnetic pole portion side of the pair of magnetic pole portions of the first spoke, and a third spoke on the other magnetic pole portion side of the first spoke. Of the pair of magnetic pole portions of the first spoke, the magnetic resistance of one magnetic pole portion is greater than that of the other magnetic pole portion. Of the pair of magnetic pole portions of the second spoke, the magnetic resistance of the other magnetic pole portion is greater than that of one magnetic pole portion. The magnetic resistance of the pair of magnetic pole portions of the third spoke is greater than that of the other magnetic pole portion of the first spoke and smaller than that of one magnetic pole portion of the first spoke. Among the plurality of spokes, another spoke at a point-symmetric position about the shaft with respect to the first spoke is defined as a fourth spoke, and another spoke at a point-symmetric position about the shaft with respect to the second spoke is defined as a fifth spoke. Of the pair of magnetic pole portions of the fourth spoke, one magnetic pole portion has a greater magnetic resistance than the other magnetic pole portion. Of the pair of magnetic pole portions of the fifth spoke, the other magnetic pole portion has a greater magnetic resistance than the one magnetic pole portion, motor.

3. The motor according to claim 2, wherein the magnetic resistances of the pair of magnetic pole portions of the third spoke are substantially equal.

4. The motor according to claim 2 or 3, wherein the number of the plurality of spokes is even.

5. A shaft, A magnetic member having a plurality of spokes extending radially from the shaft, An annularly arranged magnet, Coils wound around each of the plurality of spokes, and includes: In the radial direction, one of the magnetic member and the magnet is disposed inside the other. In the radial direction, each end of the plurality of spokes faces the magnet. Each end of the plurality of spokes has a pair of magnetic pole portions extending in opposite directions in the circumferential direction and a surface facing the magnet. The plurality of spokes includes, in the circumferential direction, a first spoke, a second spoke on one magnetic pole portion side of a pair of magnetic pole portions of the first spoke, and a third spoke on the other magnetic pole portion side of the first spoke. A groove portion is formed on the surface of the end portion of the first spoke on the second spoke side with respect to the first spoke. A groove portion is formed on the surface of the end portion of the second spoke on the first spoke side with respect to the second spoke. A groove portion is formed at the center of the third spoke in the circumferential direction on the surface of the end portion of the third spoke. Among the plurality of spokes, another spoke at a point-symmetric position with respect to the first spoke about the shaft is defined as a fourth spoke, and another spoke at a point-symmetric position with respect to the second spoke about the shaft is defined as a fifth spoke. Among the pair of magnetic pole portions of the fourth spoke, one magnetic pole portion has a larger magnetic resistance than the other magnetic pole portion. Among the pair of magnetic pole portions of the fifth spoke, the other magnetic pole portion has a larger magnetic resistance than the one magnetic pole portion, the motor.

6. The motor according to claim 5, wherein the plurality of spokes is an even number.

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