Coil and motor equipped with same

Abstract

A coil is mounted on the stator of a motor. The coil has at least: a winding part comprising a first through nth turn wound in a spiral shape; a first lead part extending from the first turn; and a second lead part extending from the nth turn. The shape of some or all of the first through nth turns differs from the other portions in the portion in which a magnet provided to the rotor and the magnetic flux generated by the coil are interlinked with the coil.

Description

[Technical field]

[0001] The present invention relates to a coil and a motor including the same. [Background technology]

[0002] In recent years, the demand for motors has been increasing in industrial and automotive applications, and there is a demand for improved motor efficiency and lower costs.

[0003] One method for improving motor efficiency is to increase the space factor of the coils placed in the stator slots. By increasing the space factor of the coils, it is possible to reduce losses caused by the current flowing through the coils when the motor is running.

[0004] As a method for improving the space factor of the coil, a configuration has been proposed in which a cast coil made of copper is disposed in the slot (see, for example, Patent Document 1).

[0005] Incidentally, IPM (Internal Permanent Magnet) motors and SPM (Surface Permanent Magnet) motors are widely used as highly efficient, low-cost motors. In these motors, a rotor with an output shaft at its center is arranged, and a stator with multiple teeth, each with a coil attached, is arranged on the outside. When a current flows through the coil, a magnetic field is generated, and the motor rotates by generating an interaction between this magnetic field and the magnetic flux generated by the magnet.

[0006] However, depending on the relative positions of the rotor and teeth, the magnetic flux generated by the magnets may interlink with the coil. In this case, eddy currents are generated in the coil, which causes energy loss (hereinafter, this loss will be referred to as eddy current loss). When eddy current loss occurs in this way, the efficiency of the motor decreases.

[0007] In order to suppress such eddy current loss, for example, Patent Document 2 discloses a configuration in which the distance between the coil and the tip faces of the teeth is made different on the lagging side and leading side of the main rotation direction of the rotor.

[0008] However, in the conventional configuration disclosed in Patent Document 2, the coils have the same shape on the lagging side and leading side in the main rotation direction of the rotor, and eddy current loss on the lagging side cannot be effectively suppressed.

[0009] In addition, depending on the structure of the motor, the magnetic flux generated by the magnet or the magnetic flux generated by the coil may link with the coil, causing eddy current loss. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] DE 102012212637 [Patent Document 2] Japanese Patent No. 5805046 Summary of the Invention

[0011] The present invention has been made in view of the above points, and an object of the present invention is to provide a coil capable of reducing eddy current loss caused by a magnet or coil provided in a rotor, and a motor including the same.

[0012] In order to achieve the above object, the coil of the present invention is a coil mounted on a stator of a motor, the motor having at least a stator, an output shaft at its axis and a plurality of magnets on its outer periphery, and a rotor arranged radially inside the stator, the coil having at least a winding portion consisting of 1st to nth turns (n ​​is an integer of 2 or more) wound in a spiral shape, a first lead portion extending from the first turn, and a second lead portion extending from the nth turn, the shape of some or all of the 1st to nth turns being different in a portion where magnetic flux generated by the magnet or coil intersects with the coil from other portions.

[0013] The motor of the present invention comprises at least a rotor having an output shaft at its axis and a plurality of magnets on its outer periphery, and a stator arranged radially outside the rotor at a predetermined distance from the rotor, and the stator has at least an annular yoke, a plurality of teeth connected to the inner periphery of the yoke, and a plurality of coils attached to each of the plurality of teeth, each of which is a coil.

[0014] According to the coil of the present invention, it is possible to reduce eddy current loss generated in the coil. According to the motor of the present invention, the reduction in eddy current loss makes it possible to suppress a decrease in efficiency. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view of a motor according to a first embodiment of the present invention. [Diagram 2] FIG. [Figure 3A] FIG. 2 is a schematic cross-sectional view of a main part of a stator. [Figure 3B] FIG. 11 is a schematic cross-sectional view of a main part of a stator for comparison. [Figure 4] 4 is a schematic cross-sectional view of a main portion of another stator according to the first embodiment. FIG. [Diagram 5] 10 is a schematic cross-sectional view of a main part of a stator according to a first modified example. FIG. [Figure 6] 13 is a schematic cross-sectional view of a main part of another stator according to the first modified example. FIG. [Figure 7] 11 is a schematic cross-sectional view of a main part of a stator according to Modification 2. FIG. [Figure 8] 11 is a schematic cross-sectional view of a main portion of another stator according to Modification 2. FIG. [Figure 9] FIG. 11 is a side view of a coil according to Modification 3. [Figure 10] 13 is a partial schematic diagram of a third side portion and a fourth side portion. FIG. [Figure 11] FIG. 11 is a side view of a coil according to Modification 4. [Figure 12] 13 is a partial schematic diagram of a third side portion and a fourth side portion. FIG. [Figure 13] 10 is a schematic diagram showing a main part of a motor according to a second embodiment of the present invention, viewed from a radial direction. FIG. [Figure 14] FIG. [Figure 15] FIG. 13 is a side view of a coil according to Modification 5. [Figure 16] FIG. 4 is a partial schematic diagram of a first coil end and a second coil end. [Figure 17] FIG. 13 is a side view of a coil according to Modification 6. [Figure 18] FIG. 4 is a partial schematic diagram of a first coil end and a second coil end. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following preferred embodiments are merely illustrative in nature and are not intended to limit the present invention, its applications, or its uses.

[0017] (Embodiment 1) [Motor configuration] FIG. 1 is a schematic cross-sectional view of a motor according to a first embodiment of the present invention. In the following description, the radial direction of the motor 1000 may be referred to as the "radial direction", the outer circumferential direction as the "circumferential direction", and the axial direction of the output shaft 210 of the motor 1000 (perpendicular to the paper surface in FIG. 1) as the "axial direction". In the radial direction, the axial center side of the motor 1000 may be referred to as the radial inner side, and the outer circumferential side as the radial outer side. In FIG. 1, a first lead portion 41 and a second lead portion 42 of the coil 40, which will be described later, are omitted from the illustration. In the axial direction, the axial center of the motor 1000 coincides with the axis of the output shaft 210.

[0018] Fig. 2 is a perspective view of coil 40. Fig. 3A is a schematic cross-sectional view of a main part of a stator. Fig. 3B is a schematic cross-sectional view of a main part of a stator for comparison. Motor 1000 has stator 100 and rotor 200. Motor 1000 has other components such as a motor case and a bearing that supports an output shaft. However, for the sake of convenience, illustration and description of these components will be omitted.

[0019] The stator 100 has an annular yoke 20, a plurality of teeth 10 connected to the inner periphery of the yoke 20 and provided at equal intervals along the inner periphery, slots 30 provided between adjacent teeth 10 in the circumferential direction, and coils 40 housed in the slots 30. The stator 100 is disposed radially outside the rotor 200 at a fixed interval from the rotor 200.

[0020] The teeth 10 and the yoke 20 are each formed, for example, by laminating electromagnetic steel sheets containing silicon or the like and then punching them. The coil 40 is a component formed by spirally winding a conductor made of copper or the like. The coil 40 is a formed coil formed by shaping a conductor made of copper or the like having a rectangular cross section. The coil 40 is attached to each of the multiple teeth 10 with an insulator 50 (see FIG. 3A) sandwiched therebetween, and is housed in the slot 30. Although not shown, an insulating coating is formed on the surface of the conductor that constitutes the coil 40. The shape of the coil 40 will be described in detail later.

[0021] It should be noted that the term "formed coil" in this specification does not include a coil in which a conductor wire having a constant width and thickness is simply wound in a spiral shape.

[0022] The formed coil is formed, for example, by preparing a plurality of rectangular plate materials having different lengths, widths, or thicknesses and joining these plate materials by cold welding, welding, or other methods. The plate materials are made of low resistance materials such as copper and aluminum.

[0023] Alternatively, the formed coil may be formed by so-called casting, in which copper or the like is melted and poured into a mold. The formed coil may be formed by bending a plate-shaped conductor wire, the width or thickness of which has been changed in advance, at a predetermined position. Alternatively, the formed coil may be formed by rolling a plate-shaped conductor wire with a constant width and thickness at a predetermined position, changing the width or thickness in the middle, and then winding the conductor wire in a spiral shape. In short, the formed coil is formed by adding another process other than winding the conductor wire, or by a method other than simple winding.

[0024] Further, depending on the phase of the current flowing through the coil 40, the coils may be referred to as coils U1 to U4, V1 to V4, and W1 to W4, respectively.

[0025] The rotor 200 has an output shaft 210, a rotor core 220 having the output shaft 210 at its axis, and a plurality of magnets 230. The plurality of magnets 230 are embedded inside the rotor core 220, and are arranged such that the north pole and the south pole are alternately arranged along the outer circumferential direction of the output shaft, facing the stator 100. The material, shape, and composition of the magnets 230 may be appropriately changed depending on the output of the motor 1000, etc. The rotor core 220 is formed, for example, by laminating electromagnetic steel sheets containing silicon or the like and then punching them.

[0026] The coils U1 to U4, V1 to V4, and W1 to W4 are connected in series. Three-phase currents of U, V, and W phases, which have a phase difference of 120° in electrical angle, are supplied to the coils U1 to U4, V1 to V4, and W1 to W4, respectively, to excite them, and a rotating magnetic field is generated in the stator 100. An interaction occurs between this rotating magnetic field and a magnetic field generated by a magnet 230 provided in the rotor 200, generating torque, and the output shaft 210 is supported by a bearing (not shown) and rotates. Depending on the phase difference between the three-phase currents of U, V, and W phases, the output shaft 210 can rotate in either the clockwise direction or the counterclockwise direction. In this specification, the rotation direction of the output shaft 210 is determined when viewed from the axial lower side.

[0027] [Structure of coil and stator components] As shown in FIG. 2, the coil 40 has a first lead portion 41, a second lead portion 42, and a winding portion 43.

[0028] The winding portion 43 has a conductive wire wound in a spiral shape for a plurality of turns. The winding portion 43 has 1st to nth turns 431 to 43n, where n is an integer of 2 or more. In this embodiment, n=7. However, this is not particularly limited, and this value can be changed as appropriate depending on the specifications of the motor 1000, etc.

[0029] The first to n-th turns 431 to 43n are stacked in this order from the center side to the outer periphery side of the motor 1000, and are housed in the slot 30.

[0030] The outer shape of each of the 1st to nth turns 431 to 43n is a rectangular ring having four sides when viewed in the radial direction. Corresponding to this shape, the winding portion 43 has a first side 44, a second side 45, a third side 46, and a fourth side 47. Each of the sides 44 to 47 includes a corresponding side of the 1st to nth turns 431 to 43n.

[0031] The first side portion 44 corresponds to the upper end side portion in the axial direction of the four sides. The second side portion 45 corresponds to the lower end side portion in the axial direction of the four sides. The third side portion 46 corresponds to one circumferential end side portion of the four sides. The fourth side portion 47 corresponds to the other circumferential end side portion of the four sides. In the following description, the first side portion 44 may be referred to as the first coil end 44, and the second side portion 45 may be referred to as the second coil end 45.

[0032] The first lead portion 41 is continuous with an end of the first turn 431 and extends upward from the first coil end 44. The second lead portion 42 is continuous with the n-th turn 43n and extends upward from the first coil end 44. The first lead portion 41 and the second lead portion 42 correspond to connection portions with wiring or a bus bar (not shown), and the insulating coating is removed from each tip. Depending on the connection position with the wiring or the bus bar, each of the first lead portion 41 and the second lead portion 42 may be bent midway.

[0033] As shown in FIG. 2, in the coil 40, the thickness of each of the first to nth turns 431 to 43n included in the third side portion 46 is thinner than the thickness of each of the first to nth turns 431 to 43n included in the fourth side portion 47.

[0034] The insulator 50 is a cylindrical part with both radially open ends, and is made of an insulating material. The provision of the insulator 50 prevents a short circuit between the coil 40 and the teeth 10, and suppresses leakage current from the coil 40 to the teeth 10. The shape of the insulator 50 can be appropriately changed depending on the shapes of the teeth 10 and the yoke 20.

[0035] When the tooth 10 to which the insulator 50 and the coil 40 are attached is connected to the yoke 20, the coil 40 is arranged so that the radially outer surface of the n-th turn 43n abuts or is close to the inner circumference of the yoke 20, as shown in Fig. 3A. The first to n-th turns 431-43n included in the third side portion 46 are arranged so as to be in radial contact with the adjacent turns. Therefore, the radially inner end face of the third side portion 46 is set back radially outward from the radially inner end face of the fourth side portion 47.

[0036] 3B, the thicknesses of the 1st to nth turns 431 to 43n are equal on the third side portion 46 and the fourth side portion 47. Therefore, the radially inner end face of the third side portion 46 and the radially inner end face of the fourth side portion 47 are located at approximately the same distance from the center of the motor 1000 in the radial direction.

[0037] 3A and 3B, the third side 46 is located on the lagging side (hereinafter simply referred to as the lagging side) of the main rotation direction of the rotor 200. The fourth side 47 is located on the leading side (hereinafter simply referred to as the leading side) of the main rotation direction of the rotor 200. As also shown in Patent Document 2, on the leading side of the teeth 10, the direction of the magnetic flux generated by the current flowing through the coil 40 is different from the direction of the magnetic flux generated by the multiple magnets 230 provided in the rotor 200 (hereinafter simply referred to as the magnetic flux generated by the magnets 230). Therefore, on the leading side, the magnetic flux generated by the magnets 230 and the magnetic flux generated by the coil 40 hardly interlink the coil 40.

[0038] On the other hand, on the lag side, the direction of the magnetic flux generated by the current flowing through the coil 40 becomes the same as the direction of the magnetic flux generated by the magnet 230 .

[0039] For this reason, in the example shown in Fig. 3B, on the lagging side, the magnetic flux generated by magnet 230 and coil 40 links with coil 40, and eddy current loss occurs in this portion. On the other hand, in the example shown in Fig. 3A, as described above, the radially inner end face of third side portion 46 is set back radially outward, so that the amount of magnetic flux linking coil 40 on the lagging side can be reduced. As a result, eddy current loss can be reduced compared to the example shown in Fig. 3B.

[0040] The magnetic flux generated by magnet 230 and the magnetic flux generated by coil 40 have a certain reach that is determined by the specifications of magnet 230 and the shape of teeth 10, and generally, they interlink with coil 40 on the side closer to rotor 200, as shown in Figures 3A and 3B.

[0041] [Effects, etc.] As described above, the coil 40 according to this embodiment is attached to the stator 100 of the motor 1000. The motor 1000 has the stator 100, an output shaft 210 at its axis, and a plurality of magnets 230 on its outer periphery. The motor 1000 has at least the rotor 200 disposed radially inside the stator 100.

[0042] The coil 40 has at least a winding portion 43 consisting of first to nth turns 431 to 43n wound in a spiral shape, a first lead portion 41 extending from the first turn 431, and a second lead portion 42 extending from the nth turn 43n.

[0043] The shapes of the 1st to nth turns 431-43n are different between the lagging side and the leading side in the main rotation direction of the rotor 200. Specifically, the thickness of each of the 1st to nth turns 431-43n included in the third side portion 46 located on the lagging side is thinner than the thickness of each of the 1st to nth turns 431-43n included in the fourth side portion 47 located on the leading side.

[0044] By configuring the coil 40 in this manner, it is possible to reduce the amount of magnetic flux generated by the magnet 230 and the coil 40 that interlinks with the coil 40 when the motor 1000 rotates in the main rotation direction. This makes it possible to reduce eddy current loss. Therefore, it is possible to suppress a decrease in the efficiency of the motor 1000.

[0045] Furthermore, if the thickness of each turn is uniformly reduced, the resistance of the coil 40 increases, increasing the loss due to Joule heat (hereinafter referred to as copper loss). Also, the space factor of the coil 40 in the slot 30 decreases. These factors raise concerns about a decrease in the efficiency of the motor 1000.

[0046] On the other hand, according to the present embodiment, by configuring the coil 40 in the above-described shape, it is possible to suppress an increase in copper loss of the coil 40 and a decrease in the space factor of the coil 40 in the slot 30. This makes it possible to suppress a decrease in the efficiency of the motor 1000.

[0047] The shapes of the coil 40 and the stator 100, particularly the insulator 50, are not limited to the examples shown in Figs. 2 and 3A, and may take other shapes.

[0048] Fig. 4 is a schematic cross-sectional view of a main portion of another stator according to embodiment 1. In the coil 40 shown in Fig. 4, similar to the coil 40 shown in Figs. 2 and 3A, the thickness of each of the 1st to nth turns 431-43n included in the third side portion 46 is thinner than the thickness of each of the 1st to nth turns 431-43n included in the fourth side portion 47.

[0049] On the other hand, a plurality of grooves 50a spaced apart from each other in the radial direction are provided on the lagging end face of the insulator 50 shown in Fig. 4. The first to n-th turns 431 to 43n included in the third side portion 46 are each housed in the groove 50a.

[0050] The coil 40 and the stator 100 may be configured in this manner. In this case, too, the radially inner end face of the third side portion 46 is recessed radially outward compared to the configuration shown in Fig. 3B, so that the amount of magnetic flux linking the coil 40 on the lagging side can be reduced. This reduces eddy current loss and suppresses a decrease in the efficiency of the motor 1000.

[0051] In the configuration shown in Fig. 4, a portion of the first to n-th turns 431-43n are housed in each groove 50a. Therefore, the radially inner end face of the third side 46 is retracted radially outwardly by a smaller amount than in the configuration shown in Fig. 3A. On the other hand, since the first to n-th turns 431-43n are arranged at intervals from each other on the delay side, the amount of magnetic flux generated in the magnet 230 and the coil 40 that links the coil 40 does not increase significantly compared to the configuration shown in Fig. 3A.

[0052] In the configuration shown in FIG. 4, instead of providing the grooves 50a in the insulator 50, insulating spacers or insulating paper may be sandwiched between the first to n-th turns 431 to 43n included in the third side portion .

[0053] The motor 1000 according to this embodiment includes at least a rotor 200 having an output shaft 210 at its axis, and a stator 100 provided radially outward of the rotor 200 with a predetermined distance therebetween.

[0054] The stator 100 includes at least an annular yoke 20, a plurality of teeth 10 connected to the inner periphery of the yoke 20, and a plurality of coils 40 attached to each of the plurality of teeth 10.

[0055] According to this embodiment, the amount of magnetic flux linking the coil 40 on the delay side is reduced, which reduces eddy current loss and suppresses a decrease in efficiency of the motor 1000.

[0056] Whether the motor 1000 rotates primarily in one direction or in both the clockwise and counterclockwise directions depends on the specifications of the motor 1000. However, there are many examples where a motor is used while primarily rotating in one direction, such as the main motor of an electric vehicle. By using the motor 1000 as such a motor, the degree of reduction in eddy current loss is increased, and the decrease in efficiency of the motor 1000 can be more reliably suppressed.

[0057] It is preferable that the coil 40 is attached to the tooth 10 in a single-layer wound state. This simplifies the structure of the coil 40 and prevents an increase in the manufacturing cost of the coil 40. It also makes it easier to design the total number of turns of the coil 40 wound around the tooth 10. However, the coil 40 may be attached to the tooth 10 in a multi-layer wound state.

[0058] From the viewpoint of reducing the amount of magnetic flux linking the coil 40 on the lag side, it is sufficient to make the shapes of the first to nth turns 431-43n of the coil 40 different between the lag side and the lead side. In other words, it is sufficient to make the volume of the first to nth turns 431-43n located on the lag side smaller than the volume of the first to nth turns 431-43n located on the lead side. It is particularly important that this relationship is established on the side closer to the rotor 200.

[0059] As described above, the coil 40 of this embodiment is a coil 40 attached to the stator of the motor 1000, and the motor 1000 has at least a stator 100, an output shaft 210 at its axis, and a rotor 200 having a plurality of magnets 230 on its outer periphery, and arranged radially inside the stator 100, and the coil 40 has at least a winding portion 43 consisting of 1st to nth (n is an integer of 2 or more) turns 431 to 43n wound in a spiral shape, a first lead portion 41 extending from the first turn 431, and a second lead portion 42 extending from the nth turn 43n, and the shape of a part or all of the 1st to nth turns 431 to 43n is different in the portion where the magnetic flux generated in the magnet 230 or the coil 40 intersects with the coil 40 from other portions.

[0060] This makes it possible to reduce eddy current loss occurring in the coil.

[0061] Furthermore, the shapes of some or all of the first to n-th turns 431 to 43n on the retarding side and the leading side of the main rotation direction of the rotor 200 may be different.

[0062] Furthermore, the thickness of each of some or all of the first to nth turns 431-43n located on the lagging side of the main rotation direction of the rotor 200 may be thinner than the thickness of each of the first to nth turns 431-43n located on the leading side of the main rotation direction of the rotor 200.

[0063] Moreover, the motor 1000 of this embodiment at least comprises a rotor 200 having an output shaft 210 at its axis and a plurality of magnets 230 on its outer periphery, and a stator 100 arranged radially outside the rotor 200 at a predetermined distance from the rotor 200, and the stator 100 at least comprises an annular yoke 20, a plurality of teeth 10 connected to the inner periphery of the yoke 20, and a plurality of coils 40 attached to each of the plurality of teeth 10, and each of the plurality of coils 40 is a coil 40 described in any of embodiments 1 and 2 and variants 1 to 6.

[0064] Also, the coil 40 may be attached to the tooth 10 in a single-layer wound state.

[0065] Accordingly, the shape of the coil 40 is not limited to the shape shown in this embodiment, but may take various shapes. Hereinafter, variations in the shape of the coil 40 will be described using modified examples.

[0066] <Variation 1> Fig. 5 is a schematic cross-sectional view of a main part of a stator according to Modification 1. Fig. 6 is a schematic cross-sectional view of a main part of another stator according to Modification 1. In Fig. 5, Fig. 6 and the subsequent drawings, the same parts as those in embodiment 1 are denoted by the same reference numerals and detailed description thereof will be omitted.

[0067] The configuration of this modified example shown in Fig. 5 differs from the configuration shown in the first embodiment in that, among the first to n-th turns 431 to 43n included in the third side portion 46 located on the lagging side, only the turn closer to the rotor 200 is thinner than the other turns. In this modified example, only two turns including the n-th turn 43n on the lagging side are thinner than the other turns. However, this is not particularly limited. It can be appropriately changed according to the specifications of the motor 1000 and the required degree of reduction in the amount of interlinkage magnetic flux, etc.

[0068] According to this modification, similarly to the configuration shown in the first embodiment, when the motor 1000 rotates in the main rotation direction, the amount of magnetic flux generated in the magnet 230 and the coil 40 that interlinks the coil 40 can be reduced. This reduces eddy current loss and suppresses a decrease in the efficiency of the motor 1000.

[0069] Furthermore, compared to the configuration shown in the first embodiment, the number of turns for thinning the thickness can be reduced in the third side portion 46. This further suppresses an increase in copper loss in the coil 40. Also, a decrease in the space factor of the coil 40 in the slot 30 can be suppressed. This further suppresses a decrease in the efficiency of the motor 1000.

[0070] As shown in Fig. 6, grooves 50a may be arranged according to the position and number of turns with reduced thickness, which can provide the same effect as the configuration shown in Fig. 5.

[0071] In addition, in the configuration shown in FIG. 6, instead of providing a groove portion 50a in the insulator 50, an insulating spacer or insulating paper may be sandwiched between the turns having a reduced thickness among the first to nth turns 431 to 43n included in the third side portion 46.

[0072] As described above, in the coil 40 of this modified example, the thickness of one or more turns closer to the rotor 200 among the first to nth turns 431 to 43n located on the lagging side of the main rotation direction of the rotor 200 is thinner than the thickness of the other turns.

[0073] <Variation 2> Fig. 7 is a schematic cross-sectional view of a main part of a stator according to Modification 2. Fig. 8 is a schematic cross-sectional view of a main part of another stator according to Modification 2.

[0074] The configuration of this modified example shown in FIG. 7 differs from the configuration shown in embodiment 1 in that the width, in this case the circumferential width, of the kth turn (k is an integer, 1≦k≦n) included in the third side portion 46 located on the lagging side is narrower than the width of the kth turn included in the fourth side portion 47 located on the leading side.

[0075] Also, the insulator 51 differs from the insulator 50 shown in the first embodiment in that the thickness of the insulator 51 is greater on the lagging side than on the leading side.

[0076] The shape of the coil 40 may be defined as shown in this modification. In this case, too, the volume of the 1st to nth turns 431-43n located on the delay side is smaller than the volume of the 1st to nth turns 431-43n located on the advance side, so that the same effect as that achieved by the configuration shown in the first embodiment can be achieved.

[0077] By forming the insulator 51 in the shape shown in FIG. 7, the gap within the slot 30 can be filled, and the stator 100 can be stabilized.

[0078] 8, the k-th turn having a narrower width on the delay side may be arranged only on the side closer to the rotor 200 among the first to n-th turns 431 to 43n. In this modification, only two turns, the n-th turn 43n and the (n-1)-th turn, correspond to the k-th turn. However, this is not particularly limited. It may be changed as appropriate according to the specifications of the motor 1000 and the required degree of reduction in the amount of interlinkage magnetic flux.

[0079] In this case, as in the configuration shown in FIG. 7, when the motor 1000 rotates in the main rotation direction, the amount of magnetic flux generated by the magnet 230 and the coil 40 that interlinks with the coil 40 can be reduced. This reduces eddy current loss and suppresses a decrease in efficiency of the motor 1000. Furthermore, compared to the configuration shown in FIG. 7, the number of turns that narrow the width from a predetermined value in the third side portion 46 can be reduced. This further suppresses an increase in copper loss in the coil 40. Furthermore, it is possible to suppress a decrease in the space factor of the coil 40 in the slot 30. This further suppresses a decrease in efficiency of the motor 1000.

[0080] As shown in FIG. 8, the thickness of the insulator 51 may be changed along the radial direction according to the position and number of turns whose width is narrowed from a predetermined value.

[0081] As described above, in the coil 40 of this modified example, the width of the kth turn (k is an integer, 1≦k≦n) located on the lagging side of the main rotation direction of the rotor 200 is narrower than the width of the turn corresponding to the kth turn located on the leading side of the main rotation direction of the rotor 200.

[0082] Furthermore, the k-th turn may be located on the side closer to the rotor 200 among the first to n-th turns 431 to 43n.

[0083] <Modification 3> Fig. 9 is a side view of the coil according to Modification 3. Fig. 10 is a partial schematic view of the third side and the fourth side. Fig. 9 is a side view of the coil 40 as viewed from the radially inner side.

[0084] The configuration of this modification shown in Figures 9 and 10 differs from the configuration shown in embodiment 1 in that a first recess 46a that exhibits a concave shape when the coil 40 is viewed in the radial direction is formed in the third side portion 46. Note that, in the coil 40 of this modification shown in Figures 9 and 10, the thicknesses of the first to n-th turns 431-43n are equal in the third side portion 46 and the fourth side portion 47, similar to the coil 40 shown in Figure 3B. The widths of the first to n-th turns 431-43n included in the third side portion 46 are equal to the widths of the first to n-th turns 431-43n included in the fourth side portion 47.

[0085] By doing so, it is possible to reduce the volume of the coil 40 at the portion where the magnetic flux generated by the magnet 230 and the coil 40 interlinks on the delay side, thereby reducing eddy current loss. This makes it possible to suppress a decrease in the efficiency of the motor 1000.

[0086] Furthermore, according to this modification, the portion of the third side portion 46 where the magnetic flux generated by the magnet 230 and the coil 40 interlinks can be simulated in advance, and the first recess 46a can be formed in that portion. In this way, the volume of the coil 40 can be increased more than in the configurations shown in the first embodiment and the first and second modifications. In other words, copper loss is further reduced, and the efficiency of the motor 1000 can be maintained high.

[0087] 9, a second recess 47a may be formed in the fourth side 47. However, any one of the following relationships needs to be satisfied between the first recess 46a and the second recess 47a.

[0088] (Condition 1) The number X1 of the first recesses 46a is greater than the number X2 of the second recesses 47a (X1>X2).

[0089] (Condition 2) The size of the first recess 46a is larger than the size of the second recess 47a. For example, as shown in Fig. 10, the axial width A1 of the first recess 46a is larger than the axial width A2 of the second recess 47a (A1>A2). Alternatively, the circumferential depth B1 of the first recess 46a is larger than the circumferential depth B2 of the second recess 47a (B1>B2).

[0090] (Condition 3) Both conditions 1 and 2 are satisfied.

[0091] In short, it is only necessary that the total volume of the first recess 46a formed in the third side portion 46 is made larger than the total volume of the second recess 47a formed in the fourth side portion 47.

[0092] Depending on the structure of the motor 1000, the magnetic flux generated by the magnet 230 and the coil 40 may be linked to the fourth side 47. In such a case, as shown in this modification, by providing the second recess 47a on the fourth side 47, the volume of the coil 40 at the portion where the magnetic flux generated by the magnet 230 and the coil 40 is linked can be reduced, even on the leading side, to reduce eddy current loss. By making the total volume of the first recess 46a larger than the total volume of the second recess 47a, it is possible to reduce eddy current loss on the lagging side where the amount of interlinking magnetic flux is large, while suppressing an increase in copper loss. This allows the efficiency of the motor 1000 to be maintained high.

[0093] The first recess 46a does not have to be formed in the entire 1st to nth turns 431 to 43n of the third side portion 46. For example, the first recess 46a may be provided in the 1st to kth turns on the side closer to the rotor 200. The same applies to the second recess 47a.

[0094] FIG. 9 shows an example in which the second recess 47a is formed in the fourth side 47. However, if the amount of magnetic flux linkage in the fourth side 47 is small, the formation of the second recess 47a may be omitted.

[0095] The positions, numbers, and sizes of the first recesses 46a and the second recesses 47a can be changed as appropriate depending on the region where the magnetic flux generated by the magnet 230 and the coil 40 interlinks with the coil 40.

[0096] As described above, in the coil 40 of this modified example, at least one first recess 46a is formed in some or all of the first to n-th turns 431 to 43n located on the retarding side of the rotor 200 in the main rotation direction.

[0097] In addition, at least one second recess 47a is formed in some or all of the first to nth turns 431 to 43n located on the leading side of the main rotation direction of the rotor, and it is preferable that the total volume of the first recess 46a is larger than the total volume of the second recess 47a.

[0098] <Variation 4> Fig. 11 is a side view of the coil according to Modification 4. Fig. 12 is a partial schematic view of the third side and the fourth side. Fig. 11 is a side view of the coil 40 as viewed from the radially inner side.

[0099] The configuration of this modified example shown in FIGS. 11 and 12 differs from the configuration shown in Modification Example 3 in that a first slit 46b penetrating the coil 40 is formed in the third side portion 46.

[0100] In this way, even if the first slit 46b is provided in the third side portion 46 of the coil 40, it is possible to achieve the same effect as the configuration shown in Modification 3. That is, it is possible to reduce the volume of the coil 40 at the portion where the magnetic flux generated by the magnet 230 and the coil 40 interlinks on the delay side, thereby reducing eddy current loss. This makes it possible to suppress a decrease in the efficiency of the motor 1000. Also, it is possible to suppress a reduction in the volume of the coil 40. This further reduces copper loss, making it possible to maintain a high efficiency of the motor 1000.

[0101] Further, the second slits 47b may be formed in the fourth side portion 47. However, any one of the following relationships needs to be established between the first slits 46b and the second slits 47b.

[0102] (Condition 4) The number X3 of the first slits 46b is greater than the number X4 of the second slits 47b (X3>X4).

[0103] (Condition 5) The size of the first slits 46b is larger than the size of the second slits 47b. For example, as shown in Fig. 12, the axial width A3 of the first slits 46b is larger than the axial width A4 of the second slits 47b (A3>A4). Alternatively, the circumferential width B3 of the first slits 46b is larger than the circumferential width B4 of the second slits 47b (B3>B4).

[0104] (Condition 6) Both conditions 4 and 5 are satisfied.

[0105] In short, it is only necessary that the total volume of the first slits 46b formed in the third side portion 46 is made larger than the total volume of the second slits 47b formed in the fourth side portion 47.

[0106] In this way, even on the leading side, the volume of the coil 40 at the portion where the magnetic flux generated by the magnet 230 and the coil 40 interlinks can be reduced, thereby reducing eddy current loss. Also, on the lagging side where the amount of interlinking magnetic flux is large, the increase in copper loss can be suppressed while reducing eddy current loss. This allows the efficiency of the motor 1000 to be maintained high.

[0107] The first slits 46b do not have to be formed in the entire 1st to nth turns 431 to 43n of the third side portion 46. For example, they may be provided in the 1st to kth turns on the side closer to the rotor 200. The same applies to the second slits 47b.

[0108] In addition, FIG. 12 shows an example in which the second slit 47b is formed in the fourth side portion 47, but if the amount of interlinking magnetic flux in the fourth side portion 47 is small, the formation of the second slit 47b may be omitted, as shown in FIG. 11.

[0109] Furthermore, the positions, numbers, and sizes of the first slits 46b and the second slits 47b can be changed as appropriate depending on the region where the magnetic flux generated by the magnet 230 and the coil 40 interlinks with the coil 40.

[0110] As described above, in the coil 40 of this modified example, at least one first slit 46b is formed in some or all of the first to n-th turns 431 to 43n located on the lagging side of the rotor 200 in the main rotation direction.

[0111] In addition, at least one second slit 47b is formed in some or all of the first to nth turns 431 to 43n located on the leading side of the main rotation direction of the rotor 200, and it is preferable that the total volume of the first slits 46b is larger than the total volume of the second slits 47b.

[0112] (Embodiment 2) Fig. 13 is a schematic diagram of a main part of a motor according to a second embodiment of the present invention as viewed from a radial direction, and Fig. 14 is a perspective view of a coil.

[0113] Typically, in the axial direction, the upper surface of the rotor core 220 is at approximately the same height as the upper surfaces of the teeth 10 and the yoke 20. Similarly, the lower surface of the rotor core 220 is at approximately the same height as the lower surfaces of the teeth 10 and the yoke 20.

[0114] However, depending on the performance required of the motor 1000, the rotor core 220 may be designed to be higher in the axial direction than the stator 100, as shown in Fig. 13. This allows more magnetic flux generated by the magnets 230 to flow to the teeth 10 and the yoke 20, thereby increasing the rotational torque of the output shaft 210. Furthermore, in this structure, the magnetic flux generated by the magnets 230 also flows outside the stator 100, so that by arranging a magnetic sensor (not shown) near the rotor 200, the magnetic field inside the motor 1000 can be easily detected.

[0115] 13, on the other hand, the magnetic flux generated by the magnet 230 enters from the axially upper side and interlinks with the first coil end 44. This increases eddy current loss in this portion, which may reduce the efficiency of the motor 1000.

[0116] Therefore, in the coil 40 shown in this embodiment and in the following modified examples 5 and 6, the configurations shown in embodiment 1 and modified examples 1 to 4 are modified and applied. This reduces the eddy current loss generated in the first coil end 44, and suppresses a decrease in efficiency of the motor 1000.

[0117] For example, as shown in FIG. 14, the thickness of each of the 1st to nth turns 431 to 43n included in the first coil end 44 is thinner than the thickness of each of the 1st to nth turns 431 to 43n included in the second coil end 45.

[0118] In this way, the volume of the first coil end 44 can be reduced, and the eddy current loss can be reduced, thereby suppressing a decrease in the efficiency of the motor 1000.

[0119] In addition, in consideration of the configurations shown in the first embodiment and the first to fourth modifications, it can be said that the coil 40 disclosed in the present specification has the following configuration.

[0120] That is, the coil 40 is attached to a stator 100 of a motor 1000. The motor 1000 has at least a stator 100, an output shaft 210 at its axis, a plurality of magnets 230 on its outer periphery, and a rotor 200 disposed radially inside the stator 100.

[0121] The coil 40 has at least a winding portion 43 consisting of first to nth turns 431 to 43n wound in a spiral shape, a first lead portion 41 extending from the first turn 431, and a second lead portion 42 extending from the nth turn 43n.

[0122] The shape of a part or all of the 1st to nth turns 431-43n is different from that of the other parts in a portion where the magnetic flux generated by the magnet 230 intersects with the coil 40. Alternatively, the volume of the 1st to nth turns 431-43n in a portion where the magnetic flux generated by the magnet 230 intersects with the coil 40 is smaller than the volume of the other parts.

[0123] As described above, the coil 40 of this embodiment has a winding portion 43 having a first coil end 44 located on one side in the axial direction, which is the axial direction of the motor 1000, and a second coil end 45 located on the other side in the axial direction, and the first to nth turns 431-43n included in the first coil end 44 and the first to nth turns 431-43n included in the second coil end 45 have partially or entirely different shapes.

[0124] In addition, it is preferable that the thickness of each of the first to nth turns 431-43n included in the first coil end 44 is thinner than the thickness of each of the first to nth turns 431-43n included in the second coil end 45.

[0125] <Variation 5> Fig. 15 is a side view of a coil according to Modification 5. Fig. 16 is a partial schematic view of a first coil end and a second coil end. Fig. 15 is a side view of coil 40 as viewed from the radially inner side.

[0126] 15 and 16 differs from the configurations shown in the first and second embodiments and modification 3 in that a third recess 44a that exhibits a concave shape when the coil 40 is viewed in the radial direction is formed in the first coil end 44. Note that in the coil 40 of this modification shown in Figs. 15 and 16, the first to n-th turns 431 to 43n have the same thickness in the first coil end 44 and the second coil end 45.

[0127] In this way, in the first coil end 44 where the amount of interlinkage magnetic flux is large, the volume of the portion where the magnetic flux generated by the magnet 230 interlinks can be reduced, thereby reducing eddy current loss. This makes it possible to suppress a decrease in the efficiency of the motor 1000.

[0128] According to this modification, the portion of the first coil end 44 where the magnetic flux generated by the magnet 230 interlinks can be simulated in advance, and the third recess 44a can be formed in that portion. In this way, the volume of the coil 40 can be increased more than in the configuration shown in the second embodiment. In other words, copper loss is further reduced. As a result, the efficiency of the motor 1000 can be maintained high.

[0129] Furthermore, the fourth recess 45a may be formed in the second coil end 45. However, any one of the following relationships needs to be established between the third recess 44a and the fourth recess 45a.

[0130] (Condition 7) The number X5 of the third recesses 44a is greater than the number X6 of the fourth recesses 45a (X5>X6).

[0131] (Condition 8) The size of the third recess 44a is larger than the size of the fourth recess 45a. For example, as shown in Fig. 16, the circumferential width A5 of the third recess 44a is larger than the circumferential width A6 of the fourth recess 45a (A5>A6). Alternatively, the axial depth B5 of the third recess 44a is deeper than the axial depth B6 of the fourth recess 45a (B5>B6).

[0132] (Condition 9) Both conditions 7 and 8 are satisfied.

[0133] In short, it is only necessary that the overall volume of the third recess 44a formed in the first coil end 44 is greater than the overall volume of the fourth recess 45a formed in the second coil end 45.

[0134] Depending on the structure of the motor 1000, the magnetic flux generated by the magnet 230 may be linked to the second coil end 45. In such a case, a fourth recess 45a may be provided in the second coil end 45. This reduces the volume of the coil 40 at the portion where the magnetic flux generated by the magnet 230 is linked, thereby reducing eddy current loss. In addition, an increase in copper loss can be suppressed. This allows the efficiency of the motor 1000 to be maintained high.

[0135] The third recess 44a does not have to be formed in the entire 1st to nth turns 431 to 43n of the first coil end 44. For example, it may be provided in the 1st to kth (k is a natural number smaller than n) turns closer to the rotor 200. The same applies to the fourth recess 45a.

[0136] 15 shows an example in which the fourth recess 45a is formed in the second coil end 45. However, if the amount of magnetic flux linkage in the second coil end 45 is small, the formation of the fourth recess 45a may be omitted.

[0137] Furthermore, the positions, numbers, and sizes of the third recesses 44a and the fourth recesses 45a can be changed as appropriate depending on the area where the magnetic flux generated by the magnet 230 interlinks with the coil 40.

[0138] As described above, in the coil 40 of this modified example, at least one third recess 44a is formed in some or all of the first to n-th turns 431 to 43n included in the first coil end 44.

[0139] In addition, it is preferable that at least one or more fourth recesses 45a are formed in some or all of the 1st to nth turns 431 to 43n included in the second coil end 45, and that the total volume of the third recesses 44a is larger than the total volume of the fourth recesses 45a.

[0140] <Variation 6> Fig. 17 is a side view of a coil according to Modification 6. Fig. 18 is a partial schematic diagram of a first coil end and a second coil end, and Fig. 11 is a side view of coil 40 as viewed from the radially inner side.

[0141] The configuration of this modified example shown in FIGS. 17 and 18 differs from the configuration shown in modified example 5 in that a third slit 44b is formed in the first coil end 44.

[0142] In this way, even if the third slit 44b is provided in the first coil end 44 of the coil 40, it is possible to achieve the same effect as the configuration shown in Modification 4. In the first coil end 44, which has a large amount of interlinkage magnetic flux, the volume of the portion where the magnetic flux generated in the magnet 230 interlinks can be reduced, thereby reducing eddy current loss. In addition, copper loss can be reduced. As a result, a decrease in the efficiency of the motor 1000 can be suppressed.

[0143] The fourth slit 45b may be formed in the second coil end 45. However, any one of the following relationships needs to be established between the third slit 44b and the fourth slit 45b.

[0144] (Condition 10) The number X7 of the third slits 44b is greater than the number Y8 of the fourth slits 45b (X7>X8).

[0145] (Condition 11) The size of the third slits 44b is larger than the size of the fourth slits 45b. For example, as shown in Fig. 18, the axial width A7 of the third slits 44b is larger than the axial width A8 of the fourth slits 45b (A7>A8). Alternatively, the circumferential width B7 of the third slits 44b is larger than the circumferential width B8 of the fourth slits 45b (B7>B8).

[0146] (Condition 12) Both conditions 10 and 11 are satisfied.

[0147] In short, it is only necessary that the overall volume of the third slits 44b formed in the first coil end 44 is made larger than the overall volume of the fourth slits 45b formed in the second coil end 45.

[0148] In this way, in the first coil end 44 where the amount of interlinking magnetic flux is large, the volume of the portion where the magnetic flux generated by the magnet 230 interlinks can be reduced, and eddy current loss can be reduced. This makes it possible to suppress a decrease in the efficiency of the motor 1000. Also, it is possible to suppress an increase in copper loss. This makes it possible to maintain a high efficiency of the motor 1000.

[0149] The third slits 44b do not have to be formed in the entire 1st to nth turns 431 to 43n of the first coil end 44. For example, they may be provided in the 1st to kth turns closer to the rotor 200. The same applies to the fourth slits 45b.

[0150] In addition, Figure 18 shows an example in which the fourth slit 45b is formed in the second coil end 45, but if the amount of interlinking magnetic flux in the second coil end 45 is small, the formation of the fourth slit 45b may be omitted, as shown in Figure 17.

[0151] Furthermore, the positions, numbers, and sizes of the third slits 44b and the fourth slits 45b can be changed as appropriate depending on the region where the magnetic flux generated by the magnet 230 interlinks with the coil 40.

[0152] As described above, in the coil 40 of this modified example, at least one third slit 44b is formed in some or all of the first to n-th turns 431 to 43n included in the first coil end 44.

[0153] In addition, it is preferable that at least one or more fourth slits 45b are formed in some or all of the 1st to nth turns 431 to 43n included in the second coil end 45, and that the total volume of the third slits 44b is larger than the total volume of the fourth slits 45b.

[0154] (Other embodiments) Note that the components shown in the embodiments including the modifications may be appropriately combined to form new embodiments. For example, the winding section 43 shown in the modification 5 may be applied to the configurations shown in the embodiments and the modifications 1 to 4 and 6.

[0155] For example, in the coil 40 shown in the third modification, a third recess 44a may be provided in the first coil end 44. A fourth recess 45a may be provided in the second coil end 45. By doing so, in the motor 1000 having the structure shown in FIG. 13, eddy current loss at the portion where the magnetic flux generated by the magnet 230 interlinks with the coil 40 can be reliably reduced. Also, an increase in copper loss can be suppressed. As a result, the efficiency of the motor 1000 can be maintained high.

[0156] In the second embodiment and the fifth and sixth modifications, the magnetic flux generated by the magnet 230 is linked to the first coil end 44. However, depending on the structure of the motor 1000, the magnetic flux generated by the magnet 230 may be linked to the second coil end 45. In such a case, it is preferable to apply the deformation applied to the first coil end 44 to the second coil end 45. For example, the thickness of each of the first to n-th turns 43n included in the second coil end 45 is made thinner than the thickness of each of the first to n-th turns 43n included in the first coil end 44. Alternatively, the total volume of the fourth recess 45a formed in the second coil end 45 is made larger than the total volume of the third recess 44a formed in the first coil end 44. Alternatively, the total volume of the fourth slit 45b formed in the second coil end 45 is made larger than the total volume of the third slit 44b formed in the first coil end 44.

[0157] This makes it possible to reliably reduce eddy current loss at the portion where the magnetic flux generated by magnet 230 interlinks with coil 40. It also makes it possible to suppress an increase in copper loss. As a result, the efficiency of motor 1000 can be maintained high.

[0158] The cross-sectional shape of the conductor that constitutes coil 40 is not particularly limited to a rectangle, and may be another shape. For example, it may be an m-sided polygon (m is an integer of 3 or more). It may also be an ellipse. [Industrial Applicability]

[0159] The coil of the present invention can reduce eddy current loss caused by the magnets and coils provided in the rotor, and is therefore useful when applied to motors that require high efficiency. [Explanation of symbols]

[0160] 10 Teeth 20 York 30 Slots 40 Coil 41 First lead 42 Second lead 43 Winding section 431~43n 1st to nth turn 44 First coil end (first side) 44a Third recess 44b 3rd slit 45 Second coil end (second side) 45a 4th recess 45b 4th slit 46 Third side (lagging side) 46a First recess 46b First slit 47 Fourth side (leading side) 47a Second recess 47b 2nd slit 50,51 Insulator 50a Groove 100 Stator 200 rotors 210 Output shaft 220 Rotor Core 230 Magnet 1000 Motor

Claims

1. A coil attached to a stator of a motor, The motor is The stator; The rotor has an output shaft at its axis and a plurality of magnets on its outer periphery, and is disposed radially inside the stator. The coil is a winding portion consisting of first to nth turns (n ​​is an integer of 2 or more) wound in a spiral shape; a first lead portion extending from the first turn; a second lead portion extending from the nth turn, The thickness of each of the first to nth turns located on the lagging side of the main rotation direction of the rotor is thinner than the thickness of each of the first to nth turns located on the leading side of the main rotation direction of the rotor.

2. A coil attached to a stator of a motor, The motor is The stator; The rotor has an output shaft at its axis and a plurality of magnets on its outer periphery, and is disposed radially inside the stator. The coil is a winding portion consisting of first to nth turns (n ​​is an integer of 2 or more) wound in a spiral shape; a first lead portion extending from the first turn; a second lead portion extending from the nth turn, A coil in which the width of each of the first to nth turns located on the lagging side of the main rotation direction of the rotor is narrower than the width of each of the first to nth turns located on the leading side of the main rotation direction of the rotor.

3. 2. The coil according to claim 1, wherein at least one first recess is formed in all of the first to n-th turns located on the retarding side in the main rotation direction of the rotor.

4. At least one second recess is formed in a part or all of the first to nth turns located on the leading side of the main rotation direction of the rotor, The coil of claim 3 , wherein a total volume of the first recess is greater than a total volume of the second recess.

5. 2. The coil according to claim 1, wherein at least one first slit is formed in all of the first to n-th turns located on the lagging side in the main rotation direction of the rotor.

6. At least one second slit is formed in a part or all of the first to nth turns located on the leading side of the main rotation direction of the rotor, The coil of claim 5 , wherein a total volume of the first slits is greater than a total volume of the second slits.

7. The winding portion includes: a first coil end located on one side in an axial direction, which is an axial direction of the motor; a second coil end located on the other side in the axial direction, The coil according to claim 1, wherein the thickness of all of the first to nth turns included in the first coil end is thinner than the thickness of the first to nth turns included in the second coil end.

8. The coil according to claim 1 , wherein at least one third recess is formed in some or all of the first to n-th turns included in the first coil end.

9. At least one fourth recess is formed in a part or all of the first to nth turns included in the second coil end, The coil according to claim 8 , wherein a total volume of the third recess is greater than a total volume of the fourth recess.

10. In the coil, The coil according to claim 1 , wherein at least one third slit is formed in some or all of the first to nth turns included in the first coil end.

11. At least one fourth slit is formed in a part or all of the first to nth turns included in the second coil end, The coil of claim 10 , wherein a total volume of the third slits is greater than a total volume of the fourth slits.

12. a rotor having an output shaft at its axis and a plurality of magnets on its outer periphery; and a stator provided radially outward of the rotor at a predetermined distance from the rotor. At least The stator includes: An annular yoke; A plurality of teeth connected to an inner periphery of the yoke; a plurality of coils attached to each of the plurality of teeth; A motor, wherein each of the plurality of coils is a coil according to any one of claims 1 to 11.

13. The motor according to claim 12 , wherein the coil is attached to the teeth in a single-layer wound state.

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