Rotor and motor

Abstract

This rotor comprises: a rotation shaft; a rotor core through which the rotation shaft is inserted; and a plurality of magnets which are disposed inside the rotor core and arranged in a ring shape centered on the rotation shaft. The rotor core has an inner core through which the rotation shaft passes and an outer core which is positioned radially outward of the inner core and which holds the plurality of magnets. The outer core has a plurality of first cores which are arranged in a ring shape centered on the rotation shaft and a pair of second cores which sandwich the plurality of first cores in the axial direction of the rotation shaft. Each of the plurality of magnets is inserted into a gap between two adjacent first cores among the plurality of first cores. Each of the pair of second cores has a plurality of core parts which correspond one-to-one with the plurality of first cores and a plurality of linking parts which successively link two adjacent core parts among the plurality of core parts.

Description

Rotor and Motor

[0001] The present disclosure relates to a rotor and a motor including the rotor.

[0002] 2. Description of the Related Art Motors are used in a variety of electrical appliances, such as household appliances and industrial appliances. For example, air conditioners use fan motors in which a rotary fan is attached to the rotating shaft of the motor.

[0003] One known motor is an interior permanent magnet (IPM) motor, which has a rotor with multiple permanent magnets embedded in the rotor core. In addition to the magnetic torque provided by the permanent magnets, the IPM motor can also generate reluctance torque due to variations in the magnitude of magnetic resistance generated in the iron core. This allows the IPM motor to be a compact, highly efficient motor.

[0004] Conventionally, an IPM motor is known that includes a rotor having a rotor core composed of an inner core through which a rotating shaft is inserted and an outer core that holds multiple permanent magnets (see, for example, Patent Document 1). In the IPM motor disclosed in Patent Document 1, the outer core is divided into multiple sections. By configuring the outer core as multiple divided cores (magnetic pole sections) that are separated from each other in this way, it is possible to improve material yield and reduce material costs.

[0005] However, dividing the outer core into multiple core segments, as in the IPM motor disclosed in Patent Document 1, increases the number of parts compared to a rotor core with an outer core whose magnetic poles are connected in a ring shape. This reduces the assembly precision of the rotor, since it is necessary to provide gaps between the core segments to facilitate assembly, in addition to the tolerances of the individual core segments. This affects cogging torque and torque ripple, resulting in reduced motor performance.

[0006] JP 2023-92367 A

[0007] The present disclosure has been made to solve such problems, and an object of the present disclosure is to provide a rotor and a motor that can suppress a decrease in assembly accuracy while suppressing material costs.

[0008] In order to achieve the above-mentioned object, one aspect of a rotor according to the present disclosure comprises a rotating shaft, a rotor core through which the rotating shaft is inserted, and a plurality of magnets disposed inside the rotor core and arranged in a ring shape around the rotating shaft, wherein the rotor core has an inner core through which the rotating shaft passes, and an outer core positioned radially outward of the inner core and holding the plurality of magnets, wherein the outer core has a plurality of first cores arranged in a ring shape around the rotating shaft, and a pair of second cores that sandwich the plurality of first cores from the axial direction of the rotating shaft, each of the plurality of magnets being inserted into a gap between two adjacent first cores in the plurality of first cores, and each of the pair of second cores having a plurality of core portions that correspond one-to-one to the plurality of first cores, and a plurality of connecting portions that sequentially connect two adjacent core portions in the plurality of core portions.

[0009] The plurality of connecting portions preferably include a first connecting portion that connects radially inner ends of the two adjacent core portions to each other.

[0010] In the axial direction of the rotary shaft, the first connecting portion is preferably located outside an upper end of the inner core.

[0011] In the axial direction of the rotating shaft, it is preferable that the first connecting portion is located on the opposite side of the inner core from the end face of the inner core, and that in the radial direction intersecting the axial direction, the first connecting portion is located outer than the inner surface of the inner core.

[0012] It is preferable that the plurality of connecting portions further include a second connecting portion connecting radially outer ends of the two adjacent core portions to each other.

[0013] It is preferable that each of the plurality of first cores has a first protrusion that protrudes in the circumferential direction from the radially outer end portion.

[0014] It is preferable that each of the plurality of first cores further has a second protrusion protruding in the circumferential direction from the radially inner end portion.

[0015] Each of the plurality of first cores may not have a protrusion that protrudes in the circumferential direction from the radially inner end portion.

[0016] It is preferable that the inner core and the outer core are integrally molded from resin, and that the outer peripheral surface of the inner core has an uneven portion formed along the circumferential direction.

[0017] It is preferable that the recess formed on the outer surface of the inner core is positioned opposite the radially inner end of each of the multiple first cores, and the protrusion formed on the outer surface of the inner core is positioned opposite each of the multiple magnets inserted into the gap between two adjacent first cores in the multiple first cores.

[0018] It is preferable that the outer peripheral surface of the inner core is provided with a notch for determining the position of a mold pin when the inner core and the outer core are integrally molded with the resin.

[0019] One aspect of a motor according to the present disclosure includes the rotor described above and a stator that generates a magnetic force acting on the rotor.

[0020] According to the present disclosure, it is possible to suppress a decrease in assembly accuracy while suppressing material costs.

[0021] FIG. 1 is an external perspective view of a motor according to an embodiment. FIG. 2 is a cross-sectional view of the motor according to an embodiment. FIG. 3 is a perspective view of a rotor according to an embodiment. FIG. 4 is an exploded perspective view of the rotor according to an embodiment. FIG. 5 is a cross-sectional view of the rotor according to an embodiment. FIG. 6 is a cross-sectional view of the rotor taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view of the rotor taken along line VII-VII in FIG. 5. FIG. 8 is an exploded perspective view of an outer core used in a rotor core in a rotor according to an embodiment. FIG. 9 is a plan view of a first core in an outer core used in a rotor core according to an embodiment. FIG. 10 is a cross-sectional perspective view of a rotor according to an embodiment. FIG. 11 is a perspective view of an outer core in a rotor core of a comparative example. FIG. 12 is a plan view of a first core in an outer core of a rotor core according to a modified example. FIG. 13 is a quarter cross-sectional view of a rotor according to an embodiment. FIG. 14 is a quarter cross-sectional view of a rotor according to a modified example.

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each of the embodiments described below represents a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that represent the superordinate concept of the present disclosure will be described as optional components.

[0023] Each figure is a schematic diagram and is not necessarily an exact representation. Therefore, the scales and the like are not necessarily the same in each figure. In all figures, the same reference numerals are used to denote substantially the same components, and redundant explanations will be omitted or simplified.

[0024] In this specification, the terms "up" and "down" do not necessarily refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition. In this embodiment, for convenience, the direction in which the axis C of the rotating shaft 10 extends is defined as the up-down direction. However, this up-down direction may differ from the actual up-down direction depending on the usage state of the motor 1, etc. In this embodiment, the radial direction of the stator 2 and the rotor 3 is defined as the "radial direction," and the rotation direction of the rotor 3 is defined as the "circumferential direction." In other words, the direction perpendicular to the axis C of the rotating shaft 10 of the rotor 3 is defined as the "radial direction," and the direction orbiting the axis C of the rotating shaft 10 is defined as the "circumferential direction." The direction in which the axis C of the rotating shaft 10 extends (the longitudinal direction of the rotating shaft 10) is defined as the "axial direction."

[0025] (Embodiment) The configuration of a motor 1 according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the appearance of the motor 1 according to the embodiment. Figure 2 is a cross-sectional view of the motor 1 according to the embodiment.

[0026] 2 , the motor 1 includes a stator 2 and a rotor 3 disposed opposite the stator 2. The motor 1 further includes a first bearing 4, a second bearing 5, a first bracket 6, and a second bracket 7.

[0027] 1 and 2, the motor 1 is a molded motor in which the stator 2 is covered with a molding resin 8. The motor 1 is a brushless motor that does not use brushes.

[0028] 2 , the stator 2 is disposed opposite the rotor 3 with a small air gap between them. The stator 2 is disposed so as to surround the rotor core 20 of the rotor 3. In other words, the motor 1 is an inner rotor type motor in which the rotor 3 is disposed inside the stator 2.

[0029] The stator 2 generates a magnetic force that acts on the rotor 3. Specifically, the stator 2 is configured so that north and south poles are generated alternately in the circumferential direction on the air gap surface between the stator 2 and the rotor core 20 of the rotor 3. The stator 2 and the rotor 3 form a magnetic circuit. The stator 2 has a stator core 2a and a winding 2b.

[0030] The stator core 2a of the stator 2 generates a magnetic force for rotating the rotor 3. The stator core 2a is, for example, a laminated body in which a plurality of steel plates are stacked in the direction in which the axis C of the rotating shaft 10 extends. Each of the plurality of steel plates is a magnetic material. Each of the plurality of steel plates is, for example, a punched electromagnetic steel plate formed into a predetermined shape. The stator core 2a is not limited to a laminated body of a plurality of steel plates. The stator core 2a may also be a bulk body made of a magnetic material.

[0031] The stator core 2a has a plurality of teeth that protrude toward the rotor 3. The plurality of teeth are arranged to protrude toward the axis C of the rotating shaft 10. The plurality of teeth are arranged at equal intervals in the circumferential direction, with slots formed between two adjacent teeth. The plurality of teeth extend radially in a direction perpendicular to the axis C of the rotating shaft 10 (radial direction).

[0032] The winding 2b is an armature winding of the stator 2. The winding 2b is a winding coil wound around the stator core 2a as a stator coil. The winding 2b is wound around multiple teeth of the stator core 2a. Specifically, the winding 2b is wound around each of the multiple teeth via an insulator 2c. In other words, multiple windings 2b are wound around the stator 2. The winding 2b is a concentrated winding coil wound around each tooth. The winding 2b is housed in a slot in the stator core 2a.

[0033] When current is applied to the windings 2b, a magnetic force is generated from each of the multiple teeth of the stator core 2a. For example, the multiple windings 2b are electrically connected as a three-phase winding so that the rotor 3 rotates as a three-phase synchronous motor. In other words, the motor 1 in this embodiment is an interior permanent magnet synchronous motor (IPMSM). In this case, the multiple windings 2b are composed of unit coils for each of the three phases, U-phase, V-phase, and W-phase, which are electrically out of phase with each other by 120 degrees. In other words, the windings 2b attached to each tooth are energized and driven by three-phase alternating current that is applied to each of the U-phase, V-phase, and W-phase units. This generates a main magnetic flux of the stator 2 in each tooth.

[0034] The stator 2 is a molded stator covered with a molded resin 8. For example, the stator 2 can be covered with the molded resin 8 by injection molding. The molded resin 8 covers the outer portion of the stator 2 over the entire circumferential direction of the stator 2. Specifically, the molded resin 8 covers the outer portions of the stator core 2a and the windings 2b. The molded resin 8 forms a housing that contains the rotor 3. Specifically, the molded resin 8 is formed in a cylindrical shape with a bottom. As shown in FIG. 1 , the molded resin 8 forms the outer shell of the motor 1.

[0035] The molded resin 8 has a plurality of protruding portions that protrude radially outward. These protruding portions are the legs of the motor 1. These protruding portions function as mounting portions for mounting the motor 1 to an installation object. The molded resin 8 is made of an insulating resin material with excellent thermal conductivity, such as polyester resin or epoxy resin. The molded resin 8 is also made of a thermosetting resin. In this embodiment, the molded resin 8 is made of unsaturated polyester (bulk molding compound (BMC)), which is a thermosetting resin. Specifically, the molded resin 8 is made of white BMC.

[0036] 2, a circuit board 9 to which the windings 2b of the stator 2 are connected is embedded in the molded resin 8. In this case, the ends of the windings 2b of each phase are connected at winding connection portions of the circuit board 9. For example, the circuit board 9 is formed with pattern wiring for electrically connecting the plurality of windings 2b for each of the U, V, and W phases. The ends of the windings 2b of each phase are electrically connected to the pattern wiring of the circuit board by solder or the like.

[0037] The rotor 3 rotates due to the magnetic force generated in the stator 2. Specifically, the rotor 3 has a rotating shaft 10. The rotor 3 rotates around an axis C of the rotating shaft 10 as the center of rotation.

[0038] The rotor 3 generates a magnetic force that acts on the stator 2. The rotor 3 has a configuration in which N and S poles that form the main magnetic flux are repeated multiple times along the circumferential direction. The direction of the main magnetic flux generated by the rotor 3 is perpendicular to the direction in which the axis C of the rotating shaft 10 extends (radial direction).

[0039] As shown in Fig. 2, the rotor 3 is disposed with an air gap between it and the stator 2. As will be described in detail later, the rotor 3 has a rotating shaft 10, a rotor core 20, and a magnet 30. The rotor 3 is an IPM rotor in which the magnet 30 is embedded in the rotor core 20. Therefore, the motor 1 is an IPM motor.

[0040] The rotating shaft 10 of the rotor 3 is supported by a first bearing 4 and a second bearing 5. The first bearing 4 and the second bearing 5 work as a pair of bearings to rotatably support the rotating shaft 10. In this way, the rotating shaft 10 is held in a rotatable state by the first bearing 4 and the second bearing 5. This allows the rotor 3 to rotate relative to the stator 2. As an example, the first bearing 4 and the second bearing 5 are ball bearings. However, the first bearing 4 and the second bearing 5 may be other bearings such as thrust bearings.

[0041] The first bearing 4 is held by a first bracket 6. The first bracket 6 is fixed to one end of the molded resin 8 in the direction in which the axis C of the rotating shaft 10 extends. The second bearing 5 is held by a second bracket 7. The second bracket 7 is fixed to the other end of the molded resin 8 in the direction in which the axis C of the rotating shaft 10 extends.

[0042] The first bracket 6 and the second bracket 7 are made of a metal material such as iron, for example. For example, the first bracket 6 and the second bracket 7 are made of a metal plate with a uniform thickness.

[0043] In the motor 1 configured as described above, when current is applied to the winding 2b of the stator 2, a field current flows through the winding 2b, generating a magnetic field. This generates magnetic flux that flows from the stator 2 toward the rotor 3. Specifically, magnetic flux that flows from each of the multiple teeth of the stator core of the stator 2 toward the rotor core 20 of the rotor 3 is generated. Meanwhile, in the rotor 3, magnetic flux that passes through the stator 2 is generated by the magnet 30 embedded in the rotor core 20. The magnetic force generated by the interaction between the magnetic flux generated by the stator 2 and the magnetic flux generated by the magnet 30 of the rotor 3 becomes torque that rotates the rotor 3, causing the rotor 3 to rotate.

[0044] The motor 1 is used in, for example, an air conditioner or other air conditioner. Specifically, the motor 1 is mounted in an outdoor unit of the air conditioner as a fan motor having a rotary fan attached to a rotary shaft 10.

[0045] Next, the detailed configuration of the rotor 3 will be described with reference to FIG. 2 and using FIGS. 3 to 10. FIG. 3 is a perspective view of the rotor 3 according to the embodiment. FIG. 4 is an exploded perspective view of the rotor 3. FIG. 5 is a cross-sectional view of the rotor 3 according to the embodiment. FIG. 6 is a cross-sectional view of the rotor 3 taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view of the rotor 3 taken along line VII-VII in FIG. 5. FIG. 8 is an exploded perspective view of the outer core 20b used in the rotor core 20 in the rotor 3 according to the embodiment. FIG. 9 is a plan view of the first core 21 in the outer core 20b used in the rotor core 20 according to the embodiment. FIG. 10 is a cross-sectional perspective view of the rotor 3 according to the embodiment. The rotating shaft 10 and the resin 20c in the rotor core 20 are omitted in FIG. 10.

[0046] As shown in FIGS. 2 to 5, the rotor 3 includes a rotating shaft 10, a rotor core 20 through which the rotating shaft 10 is inserted, and a plurality of magnets 30 held by the rotor core 20.

[0047] The rotating shaft 10 has an axis C which is the center when the rotor 3 rotates. The rotating shaft 10 extends in the direction of the axis C. The rotating shaft 10 is a long shaft. The rotating shaft 10 is a metal rod made of a metal material such as SUS (Steel Use Stainless Steel). The rotating shaft 10 is fixed to the rotor core 20. Specifically, the rotating shaft 10 penetrates the rotor core 20. The rotating shaft 10 is fixed to the rotor core 20 so as to extend on both sides of the rotor core 20 in the direction in which the axis C extends.

[0048] 2, one end of the rotating shaft 10 protrudes to the outside through the through-hole of the first bracket 6. The portion of the rotating shaft 10 protruding from the first bracket 6 serves as an output shaft. For example, a load such as a rotary fan is attached to one end of the rotating shaft 10.

[0049] The other end of the rotating shaft 10 does not protrude to the outside from the second bracket 7. However, the other end of the rotating shaft 10 may protrude to the outside from the second bracket 7. In other words, both ends of the rotating shaft 10 may protrude from each of the first bracket 6 and the second bracket 7.

[0050] As shown in Fig. 2, the rotor core 20 is disposed with an air gap between it and the stator core 2a of the stator 2. As shown in Figs. 4 to 7, the rotor core 20 has an inner core 20a and an outer core 20b. As shown in Figs. 5 and 6, the inner core 20a holds the rotating shaft 10. The outer core 20b holds a plurality of magnets 30.

[0051] The inner core 20a is located radially inward of the outer core 20b. In other words, the inner core 20a is an inner core located more inward than the outer core 20b.

[0052] The rotating shaft 10 passes through the inner core 20a. The rotating shaft 10 is fixed to the inner core 20a. Specifically, a through hole 20a1 is formed in the inner core 20a. The rotating shaft 10 is fixed to the inner core 20a by press-fitting or shrink-fitting into the through hole 20a1. As shown in FIG. 4 , the inner core 20a is a cylindrical member having an overall cylindrical shape.

[0053] 5 and 6, the outer core 20b is located radially outward from the inner core 20a. In other words, the outer core 20b is an outer core located further outward than the inner core 20a. Specifically, the outer core 20b surrounds the inner core 20a.

[0054] The inner core 20a and the outer core 20b are integrally molded with resin 20c. Specifically, the inner core 20a and the outer core 20b are injection molded, thereby molding the inner core 20a and the outer core 20b with resin 20c. Therefore, resin 20c exists between the inner core 20a and the outer core 20b as a molding resin. The shape of the portion of resin 20c existing between the inner core 20a and the outer core 20b is substantially cylindrical.

[0055] As shown in Figures 3 and 5, the resin 20c not only fills the gap between the inner core 20a and the outer core 20b, but also covers the radially inner portions of the rotor core 20 and the magnet 30. The resin 20c covering the radially inner portions of the rotor core 20 and the magnet 30 is a disk-shaped lid portion with a through hole. To adjust the balance of the rotor 3, grooves or holes may be provided in the lid portion of the resin 20c. To improve heat dissipation, structures such as fins may be provided in the lid portion of the resin 20c.

[0056] The resin 20c is made of an insulating resin material with excellent thermal conductivity, such as polyester resin or epoxy resin. The resin 20c is also made of a thermosetting resin. In this embodiment, the resin 20c is made of black BMC. The resin 20c may be made of polybutylene terephthalate (PBT) instead of BMC.

[0057] As shown in FIG. 6 , knurled projections and recesses are formed on the outer peripheral surface of the inner core 20a along the circumferential direction. Specifically, projections 20a2 and recesses 20a3 are alternately formed at equal intervals around the entire outer peripheral surface of the inner core 20a. This increases the surface area of ​​the inner core 20a and allows the resin 20c to penetrate into the recesses 20a3. This allows the resin 20c to be firmly fixed to the inner core 20a by an anchor effect. As a result, misalignment between the inner core 20a and the resin 20c during torque application, which would otherwise cause the inner core 20a to spin freely, can be prevented. In this embodiment, ten projections 20a2 and ten recesses 20a3 are provided on the outer peripheral surface of the inner core 20a. As shown in FIGS. 2 and 6 , each projection 20a2 and each recess 20a3 extends along the cylindrical axis of the cylindrical inner core 20a.

[0058] The plurality of recesses 20a3 formed on the outer peripheral surface of the inner core 20a are positioned opposite the radially inner ends of the plurality of first cores 21 of the outer core 20b, respectively. The plurality of protrusions 20a2 formed on the outer peripheral surface of the inner core 20a are positioned opposite the plurality of magnets 30 inserted into the gaps between two adjacent first cores 21 of the plurality of first cores 21, respectively.

[0059] As shown in FIG. 6 , a notch 20a4 is provided on the outer peripheral surface of the inner core 20a. The notch 20a4 is cut out so as to recess a portion of the protrusion 20a2. As an example, the notch 20a4 is cut out so as to have an arc-shaped shape in a plan view. Like the protrusion 20a2 and the recess 20a3, the notch 20a4 extends along the cylindrical axis of the cylindrical inner core 20a. The notch 20a4 is a recess for determining the position of a mold pin when the inner core 20a and the outer core 20b are integrally molded with resin 20c. Specifically, the mold pin abuts against the notch 20a4. By providing the positioning notch 20a4 on the outer peripheral surface of the inner core 20a in this manner, the inner core 20a and the outer core 20b can be easily positioned in the rotational direction.

[0060] Each of the inner core 20a and the outer core 20b is a laminated body formed by stacking multiple steel plates, which are magnetic materials, in the direction of the axis C of the rotating shaft 10. Each of the multiple steel plates in each of the inner core 20a and the outer core 20b is, for example, a punched electromagnetic steel plate formed into a predetermined shape. In each of the inner core 20a and the outer core 20b, the multiple steel plates are fixed to each other by, for example, crimping or welding. The inner core 20a and the outer core 20b are fixed to each other by a resin 20c interposed between them. The steel plates constituting each of the inner core 20a and the outer core 20b may be formed simultaneously, for example, by punching a single steel plate. In other words, the steel plates constituting the inner core 20a and the steel plates constituting the outer core 20b may be formed by the same die. This can improve manufacturing costs and assembly takt time. Furthermore, the mold structure used when molding the inner core 20a and the outer core 20b with the resin 20c can be simplified.

[0061] 3, 4, and 8, the outer core 20b has a plurality of first cores 21 and a pair of second cores 22 that sandwich the plurality of first cores 21 in the direction in which the axis C of the rotating shaft 10 extends. The first cores 21 and the second cores 22 have different shapes. In other words, the outer core 20b is composed of two types of cores, the first cores 21 and the second cores 22, that have different shapes.

[0062] The multiple first cores 21 form main magnetic pole portions of the outer core 20b. Therefore, the thickness (height in the direction of extension of the axial center C of the rotating shaft 10) of each first core 21 is greater than the thickness of each second core 22. Specifically, the number of steel plates constituting the first core 21 is greater than the number of steel plates constituting the second core 22. As an example, if the steel plates constituting each of the first core 21 and the second core 22 are 0.5 mm thick, the first core 21 is made up of 96 steel plates (48 mm thick), and the second core 22 is made up of four steel plates (2 mm thick). Since one of the purposes of the second core 22 is to ensure the strength of the entire outer core 20b, the fewer steel plates used for the second core 22, the better.

[0063] Each of the multiple first cores 21 constitutes a magnetic pole portion of the rotor core 20. As shown in FIG. 6 , the multiple first cores 21 are arranged in an annular shape around the rotating shaft 10. The multiple first cores 21 are divided cores that are arranged separately from each other in the circumferential direction. In this embodiment, ten first cores 21 are arranged in an annular shape. Each of the multiple first cores 21 has the same shape and size. In other words, each of the multiple first cores 21 is the same component. As shown in FIG. 9 , the planar shape of each of the multiple first cores 21 is substantially fan-shaped. In this case, as shown in FIG. 6 , the multiple first cores 21, each of which is approximately fan-shaped, are arranged to form a circle as a whole.

[0064] 6 and 8 , the multiple first cores 21 are arranged such that a gap 21c exists between two adjacent first cores 21. Each of the multiple magnets 30 is inserted into this gap 21c. In other words, the gap 21c constitutes a part of the magnet insertion hole 20d in the rotor core 20.

[0065] As shown in Figures 6 and 8, each of the multiple first cores 21 has a first protrusion 21a that protrudes circumferentially from its radially outer end. The first protrusion 21a is an outer protrusion provided on the outer peripheral end of the first core 21. The magnet 30 is prevented from falling off the outer core 20b by the second connecting portion 22b2 of the second core 22. However, providing the first protrusion 21a on the first core 21 further prevents the magnet 30 from falling off the outer core 20b. In other words, the first protrusion 21a is a magnet holding protrusion that holds the magnet 30 to the outer core 20b and functions as a stopper that prevents the magnet 30 from jumping out of the outer core 20b.

[0066] Each of the first cores 21 also has a second protrusion 21b protruding circumferentially from its radially inner end. The second protrusion 21b is an inner protrusion provided on the inner peripheral end of the first core 21. When the inner core 20a and the outer core 20b are integrally molded with resin 20c, the magnet 30 inserted into the magnet insertion hole 20d is prevented from falling out of the outer core 20b by the first connecting portion 22b1 of the second core 22. However, by providing the second protrusion 21b on the first core 21, the magnet 30 can be easily inserted into the gap 21c between two adjacent first cores 21 and the inserted magnet 30 can be easily held in the gap 21c. In other words, the assembly of the rotor core 20 can be improved. In this way, the second protrusion 21b also serves as a magnet holding protrusion for holding the magnet 30 to the outer core 20b and functions as a stopper that prevents the magnet 30 from jumping out of the outer core 20b.

[0067] 7 and 8 , each of the pair of second cores 22 sandwiching the plurality of first cores 21 is spoke-shaped. Each of the pair of second cores 22 has a plurality of core portions 22a and a plurality of connecting portions 22b that sequentially connect the plurality of core portions 22a. The plurality of core portions 22a and the plurality of connecting portions 22b are integrally formed. In other words, the second core 22 can be obtained by stacking a plurality of steel plates, each having a portion corresponding to the core portions 22a and a portion corresponding to the connecting portions 22b.

[0068] As shown in Fig. 8, the core portions 22a correspond one-to-one to the first cores 21. Specifically, in a plan view, the shape of each of the core portions 22a is the same as the shape of each of the first cores 21. Since the shape of the first core 21 in a plan view is substantially fan-shaped, the shape of each core portion 22a in a plan view is also substantially fan-shaped. Note that the core portions 22a are in contact with the first cores 21, respectively.

[0069] Each of the plurality of connecting portions 22 b connects two adjacent core portions 22 a among the plurality of core portions 22 a. That is, each connecting portion 22 b is a connecting bridge connecting one of two adjacent core portions 22 a to the other. Specifically, each of the plurality of connecting portions 22 b connects two circumferentially adjacent core portions 22 a.

[0070] 7 and 8, the multiple connecting portions 22b include a first connecting portion 22b1 and a second connecting portion 22b2. That is, two adjacent core portions 22a are connected by the first connecting portion 22b1 and the second connecting portion 22b2. The first connecting portion 22b1 is located radially inward of the second connecting portion 22b2. Therefore, the first connecting portion 22b1 is shorter than the second connecting portion 22b2.

[0071] The first connecting portion 22b1 is provided on the radially inner side of the side end surface of the core portion 22a. Specifically, the first connecting portion 22b1 is an inner connecting portion provided on the radially inner end of the side end surface of the core portion 22a. In other words, the first connecting portion 22b1 connects the radially inner ends of two adjacent core portions 22a.

[0072] The first connecting portion 22b1 is located on the opposite side of the inner core 20a from the end face of the inner core 20a in the direction of the axis C of the rotating shaft 10. In a radial direction intersecting the direction of the axis C of the rotating shaft 10, the first connecting portion 22b1 is located on the outer circumferential side of the inner surface of the inner core 20a.

[0073] The second connecting portion 22b2 is provided radially outward on the side end surface of the core portion 22a. Specifically, the second connecting portion 22b2 is an outer connecting portion provided on the radially outer end of the side end surface of the core portion 22a. In other words, the second connecting portion 22b2 connects the radially outer ends of two adjacent core portions 22a. The second connecting portion 22b2 is linear. However, this is not limiting. For example, the second connecting portion 22b2 may be arc-shaped.

[0074] Through holes 22c are formed in the second core 22. Each through hole 22c is an open area surrounded by two adjacent core portions 22a, the first connecting portion 22b1, and the second connecting portion 22b2. In this embodiment, ten through holes 22c are formed in the second core 22.

[0075] As shown in Fig. 7, a magnet 30 is inserted into the through hole 22c in the second core 22. In other words, the through hole 22c constitutes part of the magnet insertion hole 20d in the rotor core 20, similar to the gap 21c between two adjacent first cores 21. As shown in Fig. 4, each of the multiple magnet insertion holes 20d in the rotor core 20 is formed by the through hole 22c in the second core 22 and the gap 21c between two adjacent first cores 21. The opening shape of the through hole 22c in the second core 22 is the same as the opening shape of the gap 21c.

[0076] As shown in FIGS. 5 and 7 , the magnet 30 inserted into the magnet insertion hole 20d (through hole 22c + gap 21c) is held in the rotor core 20 by the first connecting portion 22b1 and the second connecting portion 22b2 provided on the second core 22. Specifically, the upper end of the magnet 30 inserted into the magnet insertion hole 20d is sandwiched between the first connecting portion 22b1 and the second connecting portion 22b2 of one of the pair of second cores 22. The lower end of the magnet 30 inserted into the magnet insertion hole 20d is sandwiched between the first connecting portion 22b1 and the second connecting portion 22b2 of the other of the pair of second cores 22. In this way, by providing the first connecting portion 22b1 and the second connecting portion 22b2 on the second core 22, the magnet 30 inserted into the gap 21c between two adjacent first cores 21 can be held by the second core 22. In other words, the first connecting portion 22b1 and the second connecting portion 22b2 function as stoppers that prevent the magnet 30 inserted into the magnet insertion hole 20d from falling out of the magnet insertion hole 20d.

[0077] In this embodiment, only the upper and lower ends of the outer surface 30a (the radially outer end surface of the magnet 30) of the magnet 30 inserted into the magnet insertion hole 20d are held by the second connecting portions 22b2 of each of the pair of second cores 22. Therefore, as shown in Figures 3, 5, and 6, a portion of the outer surface 30a of the magnet 30 is exposed. Specifically, the portion of the outer surface 30a of the magnet 30 other than the upper and lower ends is exposed from the rotor core 20. In other words, more than half of the outer surface 30a of the magnet 30 is exposed.

[0078] 5, in the rotor core 20 configured in this manner, the length of the inner core 20a in the direction in which the axis C of the rotating shaft 10 extends is shorter than the length of the outer core 20b in the direction in which the axis C of the rotating shaft 10 extends. In other words, if the length of the inner core 20a in the direction in which the axis C of the rotating shaft 10 extends is H1 and the length of the outer core 20b in the direction in which the axis C of the rotating shaft 10 extends is H2, then H2 > H1. Specifically, each of the upper and lower end portions of the outer core 20b is longer than the inner core 20a by a distance d (H2 = H1 + 2 × d).

[0079] Therefore, the first connecting portion 22b1 of each of the pair of second cores 22 of the outer core 20b, which are provided at both ends in the direction in which the axis C of the rotating shaft 10 extends, is located outward from the upper end of the inner core 20a in the direction in which the axis C of the rotating shaft 10 extends. Therefore, the first connecting portion 22b1 of each of the pair of second cores 22 of the outer core 20b does not face the inner core 20a in the radial direction. As a result, as shown in Figures 5 and 10, the first connecting portion 22b1 of the second core 22 of the outer core 20b and the upper end of the inner core 20a are separated by a distance D in a direction oblique to the direction in which the axis C of the rotating shaft 10 extends.

[0080] By making the length H1 of the inner core 20a and the length H2 of the outer core 20b different in this way, the distance between the outer core 20b and the inner core 20a can be increased. For example, the distance D can be ensured to be 3 mm or more. This makes it possible to suppress the occurrence of electrolytic corrosion between the outer core 20b and the inner core 20a. By making the length H1 of the inner core 20a and the length H2 of the outer core 20b different, it is also possible to suppress the amount of resin 20c used between the outer core 20b and the inner core 20a.

[0081] 3 and 5 to 7, the multiple magnets 30 are arranged inside the rotor core 20. Specifically, each of the multiple magnets 30 is inserted into a magnet insertion hole 20d of the rotor core 20. That is, each of the multiple magnets 30 is inserted into a through hole 22c in the second core 22 of the outer core 20b of the rotor core 20, and is also inserted into a gap 21c between two adjacent first cores 21 in the outer core 20b.

[0082] As shown in Figures 6 and 7, the multiple magnets 30 are arranged in an annular shape around the rotating shaft 10. In this embodiment, ten through holes 22c are formed in the second core 22 of the outer core 20b, and therefore ten magnets 30 are used. That is, the ten magnets 30 are arranged at equal intervals in the circumferential direction around the rotating shaft 10. The multiple magnets 30 are arranged so that the magnetic pole faces of the same polarity between two adjacent magnets 30 face each other. That is, between two adjacent magnets 30, the magnetic pole face that serves as the south pole of one magnet 30 faces the magnetic pole face that serves as the south pole of the other magnet 30, or the magnetic pole face that serves as the north pole of one magnet 30 faces the magnetic pole face that serves as the north pole of the other magnet 30.

[0083] The magnet 30 is a magnetized permanent magnet. The magnet 30 may be magnetized after being inserted into the rotor core 20, or may be magnetized in advance before being inserted into the rotor core 20.

[0084] The magnet 30 is a plate-like, substantially rectangular parallelepiped. The magnet 30 has a rectangular shape in plan view. Therefore, as shown in Figures 6 and 7, the cross-sectional shape of the magnet 30 when cut along a plane perpendicular to the axis C of the rotating shaft 10 is rectangular. As shown in Figure 5, the cross-sectional shape of the magnet 30 when cut along a plane passing through the axis C of the rotating shaft 10 is also rectangular. As shown in Figures 6 and 7, the magnet 30 is arranged so that its longitudinal direction is the radial direction of the rotor core 20 in plan view.

[0085] As shown in FIGS. 5 and 10 , the magnet 30 protrudes from both the upper and lower end faces of the outer core 20b in the direction of the axis C of the rotating shaft 10. Specifically, both ends of the magnet 30 in the direction of the axis C of the rotating shaft 10 protrude beyond the main surfaces of the pair of second cores 22. This ensures that even if the corners of the magnet 30 are chamfered to improve ease of insertion into the magnet insertion hole 20d and variations in the finish occur, the chamfered portions of the magnet 30 are positioned outside the outer core 20b, not inside. This prevents variations in magnetic flux due to the chamfered portions of the magnet 30. Furthermore, by having the magnet 30 protrude from the upper or lower end face of the outer core 20b, the magnetic flux of the magnet 30 can be easily detected by a Hall element disposed near the rotor 3.

[0086] 5 to 7, the magnet 30 is fixed to the rotor core 20 by the resin 20c that is used when the inner core 20a and the outer core 20b are integrally molded. In other words, the magnet 30 is fixed by the resin 20c that has entered the gap 21c between two adjacent first cores 21 in the outer core 20b. Note that instead of fixing the magnet 30 to the outer core 20b by the resin 20c, the magnet 30 may be fixed to the outer core 20b by separately filling an adhesive into the gap between the magnet 30 and the first core 21.

[0087] The magnet 30 is a ferrite magnet made of sintered ferrite. The magnet 30 is not limited to a ferrite magnet. For example, the magnet 30 may be a rare earth magnet. In this case, a neodymium rare earth magnet whose main components are neodymium, iron, and boron (Nd—Fe—B) can be used as the magnet 30.

[0088] The outer core 20b of the rotor core 20 configured in this manner uses a plurality of first cores 21 separated from one another, but the plurality of first cores 21 are sandwiched between a pair of second cores 22 having a plurality of connecting portions 22b that sequentially connect the plurality of core portions 22a in the circumferential direction. As a result, in the outer core 20b, the magnets 30 inserted between the plurality of first cores 21 are held by the connecting portions 22b, while portions of the outer surface 30a of the magnets 30 other than the connecting portions 22b are exposed from the rotor core 20. That is, as shown in FIGS. 3 and 10 , the outer peripheral surface of the rotor core 20 has a plurality of openings that expose the outer surface 30a of each magnet 30. These openings are regions surrounded by the two second connecting portions 22b2 of the pair of second cores 22 of the outer core 20b and the two side end surfaces of the two adjacent first cores 21. The shape of these openings is a slit-like rectangle extending along the direction of extension of the axis C of the rotating shaft 10.

[0089] In the rotor core 20 configured in this manner, while using multiple first cores 21, the outer core 20b can be a single component. Furthermore, by providing openings in the outer peripheral surface of the rotor core 20 and exposing the outer surfaces 30a of the magnets 30 from the rotor core 20, loss of magnetic flux generated by the rotor 3 can be reduced compared to when the outer surfaces 30a of the magnets 30 are not exposed. In other words, the output of the rotor 3 can be increased. Therefore, the magnets 30 used in the rotor 3 can be inexpensive ferrite magnets, which have a lower magnetic force than rare-earth magnets, rather than expensive rare-earth magnets, which have a high magnetic force. In other words, even if the magnets 30 are ferrite magnets, a rotor 3 that can generate a predetermined output can be realized. This allows for a low-cost rotor 3 and motor 1 to be obtained.

[0090] By exposing the outer surface 30a of the magnet 30 radially inward, when the inner core 20a and the outer core 20b are integrally molded with resin 20c by injection molding, the resin 20c enters between the magnet 30 and the outer core 20b, thereby making it possible to fix the magnet 30 more firmly.

[0091] Next, the features of the motor 1 according to this embodiment will be described, including how the technology of the present disclosure was developed.

[0092] Conventionally, IPM rotors have been known in which the rotor core is composed of an inner core and an outer core. In this case, a rotor core has been proposed in which the outer core is divided into multiple pieces. FIG. 11 is a perspective view of the outer core 20bX of a rotor core 20X of a comparative example. For example, as shown in FIG. 11 , a rotor has been proposed in which the outer core 20bX of the rotor core 20X is composed only of multiple divided cores 21X. In this way, by constructing the outer core 20bX from multiple divided cores 21X (magnetic pole portions) that are separated from each other, it is possible to improve material yield and reduce material costs.

[0093] However, dividing the outer core 20bX into multiple pieces, as in the rotor core 20X shown in FIG. 11 , increases the number of parts compared to a rotor core having an outer core with magnetic pole portions connected in a ring shape. Therefore, in a rotor core 20X in which the outer core 20bX is divided into multiple pieces, in addition to the tolerances of the individual divided cores 21X, gaps must also be provided between the divided cores 21X to allow for assembly workability. This reduces the assembly accuracy of the rotor. This, in turn, affects cogging torque and torque ripple. This, in turn, reduces motor performance. For example, the rotation speed becomes unstable, reducing controllability, and increasing noise and vibration.

[0094] As a result of intensive research, the inventors have discovered an IPM rotor with a new structure that uses split cores in the rotor core to reduce material costs while improving rotor assembly accuracy.

[0095] Specifically, the rotor core 20 in the rotor 3 according to this embodiment has an inner core 20a through which the rotating shaft 10 passes, and an outer core 20b that holds a plurality of magnets 30. The outer core 20b has a plurality of first cores 21 arranged in an annular shape around the rotating shaft 10, and a pair of second cores 22 that sandwich the plurality of first cores 21 in the direction in which the axial center C of the rotating shaft 10 extends. Each of the plurality of magnets 30 is inserted into a gap 21c between two adjacent first cores 21 in the plurality of first cores 21. Each of the pair of second cores 22 has a plurality of core portions 22a that correspond one-to-one to the plurality of first cores 21, and a plurality of connecting portions 22b that sequentially connect two adjacent core portions 22a in the plurality of core portions 22a.

[0096] The outer core 20b of the rotor core 20 configured in this manner uses a plurality of first cores 21 that are separated from one another, as described above, but sandwiches the plurality of first cores 21 between a pair of second cores 22 having a plurality of connecting portions 22b that sequentially connect the plurality of core portions 22a in the circumferential direction. This allows the outer core 20b to be made into a single component. In this way, because the rotor core 20 uses a plurality of first cores 21, material costs can be reduced. Furthermore, because the outer core 20b can be treated as a single component in the rotor core 20, a decrease in assembly accuracy can be suppressed when assembling the rotor core 20 and the rotor 3.

[0097] As described above, the rotor 3 and motor 1 according to this embodiment use the rotor core 20 having a novel structure, which makes it possible to suppress material costs and reduce deterioration in assembly accuracy. This prevents deterioration in the performance of the motor 1 due to deterioration in cogging torque and torque ripple caused by a reduction in the assembly accuracy of the rotor 3 and motor 1. For example, it is possible to suppress an increase in noise and vibration of the motor 1.

[0098] In addition, in the rotor 3 in this embodiment, the multiple connecting portions 22b in the second core 22 of the outer core 20b include a first connecting portion 22b1 that connects the radially inner ends of two adjacent core portions 22a.

[0099] With this configuration, the magnet 30 inserted into the gap 21c between two adjacent first cores 21 in the outer core 20b can be held by the first connecting portion 22b1 of the second core 22.

[0100] In addition, in the rotor 3 of this embodiment, the multiple connecting portions 22b in the second core 22 of the outer core 20b further include a second connecting portion 22b2 that connects the radially outer ends of two adjacent core portions 22a.

[0101] With this configuration, the magnet 30 inserted in the gap 21c between two adjacent first cores 21 in the outer core 20b can be held not only by the first connecting portion 22b1 on the inner circumferential side but also by the second connecting portion 22b2 on the outer circumferential side. In other words, the magnet 30 can be sandwiched from the radial direction by the first connecting portion 22b1 and the second connecting portion 22b2 provided in the radial direction of the second core 22. This makes it possible to prevent the magnet 30 from falling off the rotor core 20.

[0102] 5 and 10, in the rotor 3 according to this embodiment, the first connecting portion 22b1 of the second core 22 of the outer core 20b is located outside the upper end of the inner core 20a in the direction of the axis C of the rotating shaft 10. In other words, the first connecting portion 22b1 of the second core 22 of the outer core 20b does not face the inner core 20a in the radial direction.

[0103] This configuration makes it possible to increase the insulation distance between the outer core 20b and the inner core 20a compared to when the first connecting portion 22b1 and the inner core 20a are radially opposed to each other, thereby suppressing the occurrence of electrolytic corrosion.

[0104] (Modification) The rotor 3 and the motor 1 according to the present disclosure have been described above based on the embodiment, but the present disclosure is not limited to the above embodiment.

[0105] For example, in the above embodiment, the first core 21 in the outer core 20b of the rotor core 20 has second protrusions 21b protruding in the circumferential direction from its radially inner end. However, this is not limited to this. Fig. 12 is a plan view of the first core 21A in the outer core 20bA of a rotor core according to a modified example. Specifically, as shown in Fig. 12, the first core 21A does not have to have second protrusions 21b protruding in the circumferential direction from its radially inner end.

[0106] As in the above embodiment, when the second protrusions 21b are present at the radially inner end of the first core 21, the magnet 30 can be positioned by the second protrusions 21b. However, the magnetic flux of the magnet 30 flows to the second protrusions 21b, resulting in a loss in the generation of magnetic flux for rotational torque. In contrast, as shown in FIG. 12 , by using a first core 21A in which the second protrusions 21b are not present at the radially inner end, the magnetic flux of the magnet 30 does not flow to the second protrusions 21b. Therefore, the loss in the generation of magnetic flux for rotational torque can be eliminated. This can further improve the performance of the motor.

[0107] 12, by using a first core 21A that does not have a second protrusion 21b at the radially inner end, it is possible to stabilize the distance (air gap) between the multiple magnets 30 and the stator 2. This point will be described below.

[0108] FIG. 13 is a quarter cross-sectional view of the rotor 3 according to the embodiment. FIG. 14 is a quarter cross-sectional view of a rotor 3A according to a modified example. The radial position of the magnet 30 is determined by (a) the magnetic attraction between the magnet 30 and the first protrusions 21a on the outside of the first core 21 (i.e., the force by which the magnet 30 is pulled radially outward by the magnetic force) and (b) the pressure on the magnet 30 exerted radially outward by the flow of the resin 20c when the inner core 20a and the outer core 20b are injection-molded with the resin 20c. In other words, the radial position of the magnet 30 is determined by the magnet 30 being pulled radially outward. Therefore, if the second protrusions 21b are present at the radially inner end of the first core 21 as in the above embodiment, the resin 20c may be blocked by the second protrusions 21b during injection molding, as shown in FIG. 13 . As a result, the pressure exerted by the resin 20c on the magnet 30 toward the outside in the radial direction is weakened or becomes unstable, resulting in an unstable radial position of the magnet 30. In other words, variations in the radial positions of the multiple magnets 30 occur. On the other hand, by using the first core 21A without the second protrusions 21b shown in FIG. 12, the pressure exerted by the resin 20c toward the magnet 30 toward the outside in the radial direction during injection molding is increased, as in the rotor core 20A of the rotor 3A shown in FIG. 14. This stabilizes the radial position of the magnet 30. This suppresses variations in the radial positions of the multiple magnets 30. Therefore, the distance (air gap) between the multiple magnets 30 and the stator 2 can be stabilized. In other words, the balance of the radial magnetic flux of the rotor 3A is more stable. As a result, noise and vibration of the rotor 3A can be further reduced.

[0109] In the above embodiment, the magnet 30 inserted into the rotor core 20 has a rectangular shape when viewed from above. However, this is not limiting. For example, the shape of the magnet 30 when viewed from above may be trapezoidal or barrel-shaped.

[0110] In the above embodiment, the winding 2b of the stator 2 is wound around the stator core 2a in a concentrated winding manner. However, this is not limiting. For example, the winding 2b of the stator 2 may be wound around the stator core 2a in a distributed winding manner.

[0111] In the above embodiment, the motor 1 is a molded motor. However, this is not limiting. The technology of the present disclosure can be applied to motors other than molded motors. In other words, the technology of the present disclosure can be applied to motors in which the stator 2 is not covered with mold resin 8.

[0112] In the above embodiment, the motor 1 has been described as being applied to a fan motor in an air conditioner. However, the present invention is not limited to this. For example, the motor 1 in the above embodiment can be used in a variety of electrical appliances, including household appliances such as vacuum cleaners and refrigerators, and industrial appliances such as automotive appliances and robots.

[0113] In addition, the present disclosure also includes forms obtained by applying various modifications to the above-described embodiments and variations that would occur to those skilled in the art, or forms realized by arbitrarily combining the components and functions of the embodiments within the scope of the present disclosure. The present disclosure also includes any combination of two or more claims from the multiple claims set forth in the claims at the time of filing, provided that there is no technical contradiction. For example, when a dependent claim set forth in the claims at the time of filing is made into a multiple claim or multiple multiple claims that cite all of the superordinate claims within the scope of the technical contradiction, the present disclosure also includes any combination of all claims included in that multiple claim or multiple multiple claims.

[0114] Motors according to the present disclosure can be widely used in devices equipped with motors in various fields, including fan motors used in air conditioners and the like.

[0115] REFERENCE SIGNS LIST 1 Motor 2 Stator 2a Stator core 2b Winding 2c Insulator 3 Rotor 4 First bearing 5 Second bearing 6 First bracket 7 Second bracket 8 Molded resin 9 Circuit board 10 Rotor shaft 20 Rotor core 20a Inner core 20a1 Through hole 20a2 Convex portion 20a3 Concave portion 20a4 Notch portion 20b Outer core 20c Resin 20d Magnet insertion hole 21, 21A First core 21a First protrusion 21b Second protrusion 21c Gap 22 Second core 22a Core portion 22b Connecting portion 22b1 First connecting portion 22b2 Second connecting portion 22c Through hole 30 Magnet 30a Outer surface

Claims

1. A rotor comprising a rotating shaft, a rotor core through which the rotating shaft is inserted, and a plurality of magnets disposed inside the rotor core and arranged annularly around the rotating shaft. The rotor core has an inner core through which the rotating shaft passes and an outer core located radially outside the inner core and holding the plurality of magnets. The outer core has a plurality of first cores arranged annularly around the rotating shaft and a pair of second cores sandwiching the plurality of first cores in the axial direction of the rotating shaft. Each of the plurality of magnets is inserted into a gap between two adjacent first cores among the plurality of first cores. Each of the pair of second cores has a plurality of core portions corresponding one-to-one to the plurality of first cores and a plurality of connecting portions sequentially connecting two adjacent core portions among the plurality of core portions.

2. The rotor according to claim 1, wherein the plurality of connecting portions include a first connecting portion that connects inner ends of two adjacent core portions in the radial direction.

3. The rotor according to claim 2, wherein in the axial direction of the rotating shaft, the first connecting portion is located outside the upper end of the inner core.

4. The rotor according to claim 2, wherein in the axial direction of the rotating shaft, the first connecting portion is located on the side opposite to the side where the inner core is located from the end face of the inner core, and in the radial direction intersecting the axial direction, the first connecting portion is located on the outer peripheral side from the inner side surface of the inner core.

5. The rotor according to any one of claims 2 to 4, wherein the plurality of connecting portions further include a second connecting portion that connects outer ends of two adjacent core portions in the radial direction.

6. The rotor according to any one of claims 1 to 4, wherein each of the plurality of first cores has a first protrusion protruding in the circumferential direction from the outer end in the radial direction.

7. The rotor according to claim 6, wherein each of the plurality of first cores further has a second protrusion protruding in the circumferential direction from the inner end in the radial direction.

8. The rotor according to claim 6, wherein each of the plurality of first cores does not have a protrusion protruding in the circumferential direction from the inner end in the radial direction.

9. The inner core and the outer core are integrally formed by resin, and a plurality of concave portions and a plurality of convex portions are formed on the outer peripheral surface of the inner core along the circumferential direction. The rotor according to any one of claims 1 to 4.

10. The plurality of recesses formed on the outer peripheral surface of the inner core are respectively positioned opposite to the radially inner ends of the plurality of first cores, and the plurality of protrusions formed on the outer peripheral surface of the inner core are respectively positioned opposite to the plurality of magnets inserted into the gaps between two adjacent first cores among the plurality of first cores. The rotor according to claim 9.

11. A notch for determining the position of a mold pin when integrally molding the inner core and the outer core with the resin is provided on the outer peripheral surface of the inner core. The rotor according to claim 9.

12. A motor comprising the rotor according to any one of claims 1 to 4 and a stator that generates a magnetic force acting on the rotor.

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