Rotor of electric motor, electric motor, and method for manufacturing rotor of electric motor

Abstract

This rotor of an electric motor comprises a shaft, an iron core, a plurality of magnets, and a coupling member to which the shaft, the iron core, and the plurality of magnets are fixed, and is an integrally molded product of the shaft, the iron core, the plurality of magnets, and the coupling member. The coupling member is formed so as to cover edge portions of the plurality of magnets, and has, in the outer peripheral surface of the coupling member, at least one cutout portion recessed from the outer peripheral surface of the coupling member at each portion between two magnets from the plurality of magnets that are adjacent to each other in the direction parallel to the circumferential direction of the shaft. Each of the plurality of magnets has a side end surface partially exposed from the coupling member in at least one cutout portion, the side end surface being an end surface in the circumferential direction.

Description

Electric motor rotor, electric motor, and method for manufacturing an electric motor rotor

[0001] The present disclosure relates to a rotor for an electric motor, an electric motor, and a method for manufacturing a rotor for an electric motor, and more particularly to a rotor that is a one-piece molded product.

[0002] Conventionally, some electric motor rotors use an iron core and magnets (see, for example, Patent Document 1). To improve the performance of an electric motor, the positional accuracy of the magnets in the circumferential direction of the rotor is important. Therefore, it is necessary to position the magnets in the circumferential direction of the rotor. The rotor of Patent Document 1 is provided with a magnet positioning mechanism in the iron core. In addition, some electric motor rotors have the magnets entirely covered with resin to secure them in place (see, for example, Patent Document 2).

[0003] Patent No. 6586633 Patent No. 4552267

[0004] However, the magnet positioning mechanism in Patent Document 1 involves providing an uneven shape to the iron core itself, which may lead to a decrease in iron core yield or an increase in the cost of iron core dies. Also, in the rotor in Patent Document 2, the magnets are fixed with resin, but there is no mechanism for positioning the magnets in the circumferential direction, and the position of the magnets in the circumferential direction is not stable.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a rotor for an electric motor in which the circumferential position of the magnet is specified, an electric motor, and a method for manufacturing an electric motor rotor, in a stator in which the magnet and iron core are integrally molded from resin, without the need to provide a magnet positioning mechanism on the iron core.

[0006] The rotor of the electric motor according to the present disclosure comprises a shaft, a cylindrically formed iron core provided on the outer periphery of the shaft, a plurality of magnets formed in the shape of rectangular plates and arranged on the outer periphery of the iron core in a direction parallel to the circumferential direction of the shaft so as to face the iron core in a radial direction perpendicular to the axial direction of the shaft, and a cylindrical resin connecting member to which the shaft, iron core, and plurality of magnets are fixed. The connecting member is an integrally molded product of the shaft, iron core, plurality of magnets, and connecting member, and the connecting member is formed to cover the edge portions of the plurality of magnets. The outer periphery of the connecting member has at least one or more notches recessed from the outer periphery of the connecting member in each portion between two adjacent magnets in a direction parallel to the circumferential direction of the shaft, and each of the plurality of magnets has a side end face, which is the end face in the circumferential direction, exposed from the connecting member at at least one or more notches.

[0007] The electric motor according to the present disclosure includes a rotor of the electric motor having the above-described configuration, and a stator disposed so as to face the outer peripheral surfaces of the plurality of magnets.

[0008] The method for manufacturing a rotor of an electric motor according to the present disclosure is a method for manufacturing a rotor of an electric motor having the above-described configuration, and includes the following steps: a component placement step in which a shaft serving as the rotating shaft, an iron core formed in a cylindrical shape on the outer periphery of the shaft, and a plurality of magnets facing the iron core on the outer periphery of the iron core are placed in a mold for integral molding, and the magnets are positioned by abutting a contact surface that forms part of the mold against each side end face of the plurality of magnets in each portion between two adjacent magnets in a direction parallel to the circumferential direction of the shaft; an integral molding step in which the shaft, iron core, and multiple magnets are integrally molded using a resin material and fixed together with connecting members; and a mold removal step in which the mold is removed from the integrally molded product of the shaft, iron core, multiple magnets, and connecting members, and at least one or more notches recessed in the direction of arrangement of the shaft are formed in the outer surface of the connecting member at the position of the abutment surface of the connecting member.

[0009] The method for manufacturing a rotor of an electric motor according to the present disclosure is a method for manufacturing a rotor of an electric motor having the above-described configuration, and includes a component placement process in which a shaft serving as the rotating shaft, an iron core formed in a cylindrical shape on the outer periphery of the shaft, a plurality of magnets facing the iron core on the outer periphery of the iron core, and a block having a higher melting point than a connecting member are placed in a mold for integral molding, and the plurality of magnets are positioned by abutting the blocks against the side end faces of each of the plurality of magnets in each portion between two adjacent magnets in a direction parallel to the circumferential direction of the shaft, and an integral molding process in which the shaft, iron core, multiple magnets, and block are integrally molded using a resin material, and the shaft, iron core, multiple magnets, and block are fixed together by a connecting member.

[0010] The electric motor rotor, electric motor, and method for manufacturing an electric motor rotor according to the present disclosure are integrally molded products comprising a shaft, an iron core, multiple magnets, and a connecting member. The connecting member is formed to cover the edges of the multiple magnets, and the outer surface of the connecting member has at least one or more notches recessed from the outer surface of the connecting member at each of the portions between two adjacent magnets in a direction parallel to the circumferential direction of the shaft. At least one or more notches in each of the multiple magnets expose a portion of the circumferential end face (i.e., the side end face) of the magnets in the at least one notch. The electric motor rotor can be easily positioned circumferentially by pressing the contact surface of a positioning member, which is integral with or separate from the mold for integral molding, against the side end face of the magnet in the portion where the notch is formed during integral molding. Therefore, the electric motor rotor can identify the circumferential position of the magnet without requiring a magnet positioning mechanism in the iron core.

[0011] 10 is a conceptual diagram showing the inside of an electric motor according to embodiment 1. FIG. 11 is a perspective view of a rotor according to embodiment 1. FIG. 12 is a schematic cross-sectional view of the rotor according to embodiment 1. FIG. 13 is a conceptual diagram showing the relationship between magnets and coupling members in the rotor according to embodiment 1, when viewed in a radial direction perpendicular to the axial direction of the shaft. FIG. 14 is a conceptual diagram showing an example of a manufacturing process for the rotor according to embodiment 1. FIG. 15 is another conceptual diagram showing the relationship between magnets and coupling members in the rotor according to embodiment 1, when viewed in a radial direction perpendicular to the axial direction of the shaft. FIG. 16 is a conceptual diagram showing the relationship between magnets and coupling members in the rotor according to embodiment 1, when viewed in a radial direction perpendicular to the axial direction of the shaft. FIG. 17 is a perspective view showing the relationship between magnets and coupling members in the rotor according to embodiment 2. FIG. 18 is a side view of a cutout portion in the rotor according to embodiment 2. FIG. 19 is a conceptual diagram showing a cross section along the axial and radial directions of a rotor according to embodiment 3. FIG. 19 is a conceptual diagram showing part C of FIG. 10 of the rotor according to embodiment 3. FIG. 19 is a side view of a cutout portion in the rotor according to embodiment 3. FIG. 19 is a conceptual diagram showing part C of FIG. 10 of the rotor according to the comparative example.

[0012] Hereinafter, a rotor for an electric motor, an electric motor, and a method for manufacturing a rotor according to embodiments will be described with reference to the drawings. Note that in the following drawings, including FIG. 1, the relative dimensional relationships and shapes of the components may differ from those in reality. In addition, in the following drawings, components with the same reference numerals are the same or equivalent, and this applies throughout the entire specification. In addition, to facilitate understanding, terms indicating directions (e.g., "up," "down," "right," "left," "front," "rear," etc.) are used as appropriate, but these notations are written in this manner only for the convenience of explanation and do not limit the arrangement or orientation of devices or components.

[0013] Embodiment 1. [Configuration of electric motor 1] Fig. 1 is a conceptual diagram showing the interior of an electric motor 1 according to embodiment 1. As shown in Fig. 1, the electric motor 1 is, for example, a brushless DC motor, and includes a cylindrical stator 2 and a rotor 3 housed inside the stator 2. In other words, the electric motor 1 includes the rotor 3 and the stator 2 disposed so as to face the outer peripheral surfaces of a plurality of magnets 20 (described later) of the rotor 3. The electric motor 1 also includes a motor housing 5 having an accommodation space formed therein for accommodating the rotor 3, and a printed circuit board 12 on which a Hall element for detecting the magnetic pole position of the rotor 3 is mounted.

[0014] 1, the stator 2 includes stator pole pieces formed by stacking multiple electromagnetic steel plates, coils through which current supplied from a power source flows, and insulators attached to the stator pole pieces to insulate the coils. The stator 2 is configured by arranging stator pole pieces with insulators attached in a circular shape. The stator 2 has coils wound around the stator pole pieces with insulators attached. The casing 6 of the electric motor 1 is formed, for example, by placing the stator 2 in a mold having a predetermined shape and injecting molding resin into the mold.

[0015] The motor housing 5 includes a cylindrical casing 6 with a bottom, a bearing housing 7 that covers the open side of the casing 6, and a bracket cover 11 that has a sheet metal cover 10. The motor housing 5 is integrally fixed with a molded resin, with the inner peripheral surface of the stator 2 exposed to the inner surface of the casing 6. The motor housing 5 is also provided with one bearing 9a and the other bearing 9b. The one bearing 9a is attached to the bottom wall portion 16 of the casing 6, and the other bearing 9b is attached to the bearing housing 7. The casing 6 and the bearing housing 7 are formed from a molded resin. The molded resin is, for example, a thermosetting resin such as unsaturated polyester.

[0016] The rotor 3 is disposed radially inside the cylindrical stator 2 so as to be coaxial with the stator 2. The rotor 3 is fixed to the motor housing 5 by press-fitting a shaft 8. The shaft 8 is rotatably supported by the motor housing 5 via one bearing 9a and the other bearing 9b. The printed circuit board 12 is fixed by welding or the like to a board holder 13 disposed between the end face of the rotor 3 and the bearing housing 7.

[0017] [Configuration of rotor 3] Fig. 2 is a perspective view of the rotor 3 according to embodiment 1. Fig. 3 is a schematic cross-sectional view of the rotor 3 according to embodiment 1. Note that Fig. 2 also shows bearing 9a, and Fig. 3 also shows bearings 9a and 9b. Figs. 2 and 3 also conceptually show a mold 210 for integral molding. The mold 210 for integral molding is separated and removed from the rotor 3. The rotor 3 includes a shaft 8 that serves as a rotation axis, and a cylindrically formed iron core 17 that is provided on the outer periphery of the shaft 8.

[0018] The rotor 3 also includes a plurality of magnets 20 formed in the shape of rectangular plates, which are arranged on the outer periphery of the iron core 17 in a direction parallel to the circumferential direction of the shaft 8 and are arranged so as to face the iron core 17 in a radial direction perpendicular to the axial direction of the shaft 8. The rotor 3 also includes a cylindrical resin connecting member 19 to which the shaft 8, the iron core 17, and the plurality of magnets 20 are fixed.

[0019] The rotor 3 is an integrally molded product of the shaft 8, the iron core 17, the plurality of magnets 20, and the connecting member 19. That is, the rotor 3 is formed by integrally molding the shaft 8, the iron core 17, and the plurality of magnets 20 with the resin that constitutes the connecting member 19.

[0020] The shaft 8 is a rotary shaft for transmitting power and is formed in a rod shape. The shaft 8 is formed in a substantially cylindrical shape.

[0021] The iron core 17 is a yoke and is used to form a magnetic circuit. The iron core 17 is formed in a cylindrical shape. When viewed in the axial direction of the shaft 8, the iron core 17 may be composed of a single member formed in an annular shape. Alternatively, when viewed in the axial direction of the shaft 8, the iron core 17 may be composed of a plurality of iron core pieces arranged in an annular shape. In other words, the iron core 17 may be composed of a single member, or may be composed of a plurality of iron core pieces divided in the circumferential direction around the shaft 8. The iron core 17 is formed, for example, by stacking a plurality of thin plates along the axial direction of the shaft 8.

[0022] The magnets 20 are permanent magnets. When viewed in a radial direction perpendicular to the axial direction of the shaft 8, the magnets 20 are formed in the shape of a rectangular plate. The rotor 3 has a plurality of magnets 20. The plurality of magnets 20 are arranged outside the iron core 17 in the radial direction perpendicular to the axial direction of the shaft 8. The plurality of magnets 20 are arranged so as to face the iron core 17 in the radial direction perpendicular to the axial direction of the shaft 8. The plurality of magnets 20 are arranged in an annular shape when viewed in the axial direction of the shaft 8. A part of the connecting member 19 is arranged between two adjacent magnets 20 in the circumferential direction of the shaft 8.

[0023] The connecting member 19 is a cylindrical resin member that is molded integrally with the shaft 8, the iron core 17, and the plurality of magnets 20. The connecting member 19 secures the shaft 8, the iron core 17, and the plurality of magnets 20 together, and connects the shaft 8, the iron core 17, and the plurality of magnets 20 together. The connecting member 19 is made of a resin for molding, such as a thermoplastic resin or a thermosetting resin.

[0024] 2 and 3, the connecting member 19 has a cylindrical outer circumferential portion 191 that fixes the iron core 17 and the plurality of magnets 20, a cylindrical inner circumferential portion 193 that fixes the shaft 8, and an intermediate portion 192 that forms a portion connecting the outer circumferential portion 191 and the inner circumferential portion 193. At least one or more notches 195 are formed in the outer circumferential portion 191.

[0025] The outer peripheral portion 191 is molded integrally with the iron core 17 and the plurality of magnets 20. The outer peripheral portion 191 is formed in a cylindrical shape, with the iron core 17 arranged on the inner peripheral side and the plurality of magnets 20 arranged on the outer peripheral side. A portion of the magnets 20 is exposed on the outer peripheral surface 19a of the outer peripheral portion 191. When viewed in the radial direction perpendicular to the axial direction of the shaft 8, the outer periphery of the magnets 20 is covered by the outer peripheral portion 191. The inner peripheral portion 193 is formed in a cylindrical shape and is molded integrally with the shaft 8.

[0026] The intermediate portion 192 is configured by, for example, a plurality of ribs 192a. The plurality of ribs 192a are formed radially from the center of the shaft 8 and are spaced apart from one another in the circumferential direction of the shaft 8. Note that the intermediate portion 192 need only configure a portion that connects the outer circumferential portion 191 and the inner circumferential portion 193, and is not limited to a configuration of a plurality of ribs 192a.

[0027] Fig. 4 is a conceptual diagram showing the relationship between magnets 20 and connecting members 19 in rotor 3 according to embodiment 1 when viewed in a radial direction perpendicular to the axial direction of shaft 8. Fig. 4 shows part A in Fig. 2 as an example. The relationship between magnets 20 and connecting members 19 will be described using Figs. 2 and 4.

[0028] The connecting member 19 is formed so as to cover the edge portions of each of the plurality of magnets 20, which are formed in the shape of a rectangular plate. The connecting member 19 has at least one or more notches 195 recessed in the arrangement direction of the shaft 8 on the outer circumferential surface 19a of the connecting member 19, in each portion between two adjacent magnets of the plurality of magnets 20 in a direction parallel to the circumferential direction of the shaft 8. The rotor 3 has the notches 195 in the connecting member 19, which is made of resin and covers the peripheries of the magnets 20.

[0029] One or more notches 195 may be formed along the outer periphery of magnet 20. It is sufficient that there be one or more notches 195 around magnet 20. As shown in FIG. 4 , in rotor 3 of embodiment 1, notch 195 is formed along the axial direction of shaft 8. In rotor 3 of embodiment 1, notch 195 is formed along side end face 21, which is the end face of magnet 20 in the circumferential direction.

[0030] 4, in at least one or more cutouts 195, a portion of the side end face 21, which is the end face in the circumferential direction, of each of the plurality of magnets 20 is exposed from the connecting member 19. That is, in the rotor 3, cutouts are provided in the resin located on the circumferential side face of the magnet 20, and a portion of the circumferential side face of the magnet 20 is not covered by the connecting member 19, which is an integrally molded resin.

[0031] 5 is a conceptual diagram showing an example of a manufacturing process for the rotor 3 according to the first embodiment. In manufacturing the rotor 3, a positioning member 200, which is part of a mold 210 for integral molding (see FIG. 3 ), is placed in the cutout 195. The positioning member 200 is formed integrally with the mold 210 for integral molding. The positioning member 200 faces the side end face 21 of the magnet 20 in the circumferential direction of the rotor 3 and has abutment surface 201, which is a contact surface that abuts against the side end face 21. By providing the abutment surface 201, which is a contact surface, on the positioning member 200 of the mold 210 for integral molding, and pressing the side face of the magnet 20 against the abutment surface 201, the magnet 20 of the rotor 3 can be positioned in the circumferential direction.

[0032] To improve the performance of the electric motor 1, the positional accuracy of the magnets 20 in the circumferential direction of the rotor 3 is important. Therefore, it is necessary to position the magnets 20 in the circumferential direction of the rotor 3. The reason why positioning of the magnets 20 is necessary is that, for example, when the magnets 20 are placed in the mold 210 and the resin that will ultimately become the connecting member 19 is poured into the mold 210, the position of the magnets 20 may become misaligned, and positioning is necessary to prevent this.

[0033] When the positioning member 200 is removed from the rotor 3 after integral molding, a notch 195 is formed in the outer peripheral surface 19a of the connecting member 19 at the position where the positioning member 200 was located. As described above, the notch 195 exposes a part of the side end surface 21 of the magnet 20, which is the end surface in the circumferential direction.

[0034] The shape of the positioning member 200 is not limited as long as it has an abutment surface portion 201 that is an abutment surface facing the side end surface 21 of the magnet 20. For example, the positioning member 200 may be formed in a rectangular parallelepiped shape when placed in the cutout portion 195. Alternatively, the positioning member 200 may have an abutment surface portion 201 that faces the side end surface 21 of the magnet 20 and a portion that covers the outer peripheral surface of the magnet 20, and may have an L-shaped cross section perpendicular to the axial direction.

[0035] Here, a method for manufacturing the rotor 3 of the electric motor 1 will be described. The method for manufacturing the rotor 3 of the electric motor 1 includes a component placement step, an integral molding step, and a mold removal step. In the component placement step, the shaft 8 serving as the rotation axis, the iron core 17 formed in a cylindrical shape on the outer periphery of the shaft 8, and a plurality of magnets 20 facing the iron core 17 on the outer periphery of the iron core 17 are placed in a mold 210 for integral molding. In addition, in the component placement step, the plurality of magnets 20 are positioned circumferentially by abutting a contact surface 201, which is part of the mold 210, against a side end surface 21 of each of the plurality of magnets 20 in a portion between two adjacent magnets in a direction parallel to the circumferential direction of the shaft 8.

[0036] In the integral molding process, the shaft 8, iron core 17, and multiple magnets 20 are integrally molded using a resin material, and the shaft 8, iron core 17, and multiple magnets 20 are fixed together by connecting members 19. In the mold removal process, the mold 210 is removed from the integrally molded product of the shaft 8, iron core 17, multiple magnets 20, and connecting member 19. Also in the mold removal process, at least one or more notches 195 are formed in the connecting member 19, recessed from the outer circumferential surface 19a of the connecting member 19 at the position of the abutment surface 201 in the arrangement direction of the shaft 8. In other words, in the method for manufacturing the rotor 3, the magnets 20 can be positioned circumferentially by the abutment surface 201 of the positioning member 200, which is placed in the cutout 195.

[0037] 6 is another conceptual diagram showing the relationship between magnets 20 and connecting members 19 in rotor 3 according to embodiment 1 when viewed in the radial direction perpendicular to the axial direction of shaft 8. Rotor 3 may have blocks 197 in cutout portions 195. Blocks 197 are positioning members 200a that position magnets 20 in the circumferential direction in place of positioning members 200 that are configured integrally with integral molding die 210. Blocks 197 are positioning members 200a that are configured separately from integral molding die 210. Blocks 197 are placed in integral molding die 210 during integral molding.

[0038] 6 , connecting member 19 may have a block 197 with a higher melting point than connecting member 19 disposed in at least one or more cutouts 195. Block 197 faces side end face 21 of magnet 20 in the circumferential direction of rotor 3 and has a contact surface 201 that is a contact surface that abuts against side end face 21. Block 197 is provided with a contact surface 201 that is a contact surface, and by pressing the side of magnet 20 against a contact surface 201, rotor 3 can position magnet 20 in the circumferential direction.

[0039] When the mold 210 for integral molding is removed from the rotor 3 after integral molding, the block 197 is disposed in the cutout 195. That is, in the rotor 3 shown in FIG. 6 , the block 197 is integrally molded together with the magnet 20 and the like. In the portion of the rotor 3 where the block 197 is disposed, the connecting member 19 made of resin is not present, and the cutout 195 is formed. As described above, in the cutout 195, part of the side end face 21 of the magnet 20, which is the end face in the circumferential direction, is exposed from the connecting member 19. In the rotor 3, part of the side end face 21 of the magnet 20 is covered by the block 197 in the cutout 195.

[0040] The shape of block 197 is not limited as long as it has a contact surface portion 201 that is a contact surface facing side end surface 21 of magnet 20. For example, block 197 may be formed in a rectangular parallelepiped shape when placed in cutout portion 195. Alternatively, block 197 may have a contact surface portion 201 that faces side end surface 21 of magnet 20 and a portion that covers the outer peripheral surface of magnet 20, and may have an L-shaped cross section perpendicular to the axial direction.

[0041] The block 197 is formed from a material having a higher melting point than the resin used for integral molding that forms the connecting member 19. It is also desirable that the block 197 be formed from a material having a higher melting point than the mold 210 used for integral molding. The material of the block 197 is not limited, and may be, for example, a resin or a metal. However, it is desirable that the block 197 be formed from a non-magnetic material.

[0042] Here, a method for manufacturing the rotor 3 shown in Figure 6 will be described. The method for manufacturing the rotor 3 includes a component placement process and an integral molding process. In the component placement process, the shaft 8 serving as the rotation axis, the iron core 17 formed in a cylindrical shape on the outer periphery of the shaft 8, and a plurality of magnets 20 facing the iron core 17 on the outer periphery of the iron core 17 are placed in an integral molding die 210. In the component placement process, a block 197 having a higher melting point than the connecting member 19 is placed in the integral molding die 210. In the component placement process, the plurality of magnets 20 are positioned by abutting the block 197 against the side end surfaces 21 of each of the plurality of magnets 20 in the portions between two adjacent magnets 20 in the direction parallel to the circumferential direction of the shaft 8.

[0043] In the integral molding step, the shaft 8, iron core 17, the plurality of magnets 20, and block 197 are integrally molded using a resin material, and the shaft 8, iron core 17, the plurality of magnets 20, and block 197 are fixed together by connecting member 19. The manufacturing method of rotor 3 may also include a mold removal step. In the mold removal step, mold 210 is removed from the integrally molded product of shaft 8, iron core 17, the plurality of magnets 20, block 197, and connecting member 19. In rotor 3 removed from mold 210, block 197 is arranged in notch 195 of connecting member 19.

[0044] [Operation and Effects of Rotor 3 and Electric Motor 1] The rotor 3 of the electric motor 1 according to the first embodiment is an integrally molded product of the shaft 8, the iron core 17, the plurality of magnets 20, and the connecting member 19. The connecting member 19 is formed so as to cover the edge portions of the plurality of magnets 20, and has at least one or more notches 195 in the outer circumferential surface 19a of the connecting member 19 in each portion between two adjacent magnets 20 in a direction parallel to the circumferential direction of the shaft 8. The notches 195 are portions of the outer circumferential surface 19a of the connecting member 19 that are recessed from the outer circumferential surface 19a of the connecting member 19. In at least one or more notches 195, a portion of the side end face 21, which is the end face in the circumferential direction, of each of the plurality of magnets 20 is exposed from the connecting member 19. The rotor 3 of the electric motor 1 can easily position the magnet 20 in the circumferential direction by pressing the contact surface 201, which is the contact surface of the positioning member 200 that is integral with the mold 210 for integral molding, against the side end surface 21 of the magnet 20 at the portion where the notch 195 is formed during integral molding. Therefore, the rotor 3 of the electric motor 1 does not need to provide a positioning mechanism for the magnet 20 on the iron core 17, and the position of the magnet 20 in the circumferential direction can be identified.

[0045] FIG. 7 is a conceptual diagram showing the relationship between the magnets 20 and the connecting member 19 in a rotor 3L according to a comparative example, as viewed in a radial direction perpendicular to the axial direction of the shaft 8. The rotor 3L according to the comparative example does not have a cutout 195 formed in the connecting member 19. The rotor 3L according to the comparative example does not have a block 197 formed in the connecting member 19. The rotor 3L according to the comparative example does not have a cutout 195 formed in the connecting member 19, so it is not possible to position the positioning member 200 that would form the cutout 195 during integral molding. The rotor 3L according to the comparative example does not have a positioning member 200 during integral molding, making it difficult to position the multiple magnets 20 in the circumferential direction. Alternatively, the rotor 3L according to the comparative example does not have a block 197 formed in the connecting member 19, making it difficult to position the multiple magnets 20 in the circumferential direction.

[0046] In contrast, in the rotor 3, the circumferential positioning of the magnet 20 can be easily performed by pressing the abutment surface 201, which is the abutment surface of the positioning member 200 that is integral with the mold 210 for integral molding, against the side end surface 21 of the magnet 20 in the portion where the cutout 195 is formed during integral molding. Therefore, in the rotor 3 of the electric motor 1, the position of the magnet 20 in the circumferential direction can be specified without the need to provide a positioning mechanism for the magnet 20 in the iron core 17. In the rotor 3, the circumferential positioning of the magnet 20 can be easily performed by using the positioning member 200 or the like in the cutout 195, i.e., in the portion where the magnet 20 is not covered with the resin for integral molding.

[0047] Furthermore, connecting member 19 has a cylindrical outer peripheral portion 191 that secures core 17 and the multiple magnets 20, a cylindrical inner peripheral portion 193 that secures shaft 8, and an intermediate portion 192 that connects outer peripheral portion 191 and inner peripheral portion 193. At least one notch 195 is formed in outer peripheral portion 191. In rotor 3, magnet 20 can be easily positioned circumferentially by pressing a contact surface 201, which is the contact surface of a positioning member 200 of a mold 210 for integral molding, against a side end surface 21 of magnet 20 at the portion where notch 195 is formed in outer peripheral portion 191 during integral molding. Therefore, rotor 3 of electric motor 1 does not need to provide a magnet 20 positioning mechanism on core 17, and the position of magnet 20 in the circumferential direction can be identified.

[0048] The manufacturing method of the rotor 3 of the electric motor 1 includes a component placement step, an integral molding step, and a mold removal step. In the component placement step, the shaft 8 serving as the rotation axis, the iron core 17 formed in a cylindrical shape on the outer periphery of the shaft 8, and a plurality of magnets 20 facing the iron core 17 on the outer periphery of the iron core 17 are placed in an integral molding mold 210. In the component placement step, the plurality of magnets 20 are positioned by abutting a contact surface 201, which is part of the mold 210, against a side end surface 21 of each of the plurality of magnets 20 in a portion between two adjacent magnets in a direction parallel to the circumferential direction of the shaft 8. In the integral molding step, the shaft 8, the iron core 17, and the plurality of magnets 20 are integrally molded using a resin material, and the shaft 8, the iron core 17, and the plurality of magnets 20 are fixed together using a connecting member 19. In the mold removal process, the mold 210 is removed from the integrally molded product of the shaft 8, the iron core 17, the plurality of magnets 20, and the connecting member 19. In addition, in the mold removal process, at least one or more notches 195 recessed in the arrangement direction of the shaft 8 are formed in the outer peripheral surface 19a of the connecting member 19 at the position of the abutment surface 201 of the connecting member 19.

[0049] The manufacturing method of the rotor 3 of the electric motor 1 allows the magnets 20 to be positioned in the circumferential direction by the abutment surface 201 of the positioning member 200 that is placed in the cutout 195. The circumferential positioning of the magnets 20 can be easily achieved by pressing the abutment surface 201, which is the abutment surface of the positioning member 200 of the mold 210 for integral molding, against the side end surface 21 of the magnet 20 in the portion of the outer circumferential portion 191 where the cutout 195 is formed during integral molding. Therefore, the rotor 3 of the electric motor 1 does not require a magnet 20 positioning mechanism to be provided on the iron core 17, and the position of the magnets 20 in the circumferential direction can be identified.

[0050] Furthermore, a block 197 having a higher melting point than the connecting member 19 is disposed in at least one notch 195 of the connecting member 19. In the rotor 3 of the electric motor 1, a block 197 separate from the mold 210 for integral molding is disposed in the portion where the notch 195 is formed during integral molding. In the rotor 3 of the electric motor 1, the abutment surface 201, which is the abutment surface of the block 197, is pressed against the side end surface 21 of the magnet 20, thereby easily positioning the magnet 20 in the circumferential direction. Therefore, the rotor 3 of the electric motor 1 does not need to be provided with a positioning mechanism for the magnet 20 on the iron core 17, and the position of the magnet 20 in the circumferential direction can be identified. When the rotor 3 includes the block 197, the number of parts increases compared to when the rotor 3 is positioned using the mold 210 for integral molding, such as the positioning member 200. However, this is effective when it is desired to reduce manufacturing costs because rotors 3 for multiple models, such as rotors 3 with different pole numbers, can be molded using the same mold.

[0051] The manufacturing method of the rotor 3 of the electric motor 1 also includes a component placement process and an integral molding process. In the component placement process, the shaft 8, the iron core 17 formed in a cylindrical shape on the outer periphery of the shaft 8, a plurality of magnets 20 facing the iron core 17 on the outer periphery of the iron core 17, and a block 197 having a melting point higher than that of the connecting member 19 are placed in an integral molding die 210. In the component placement process, the plurality of magnets 20 are positioned by abutting the blocks 197 against the side end faces 21 of each of the plurality of magnets 20 in the portions between two adjacent magnets 20 in a direction parallel to the circumferential direction of the shaft 8. In the integral molding process, the shaft 8, the iron core 17, the plurality of magnets 20, and the block 197 are integrally molded using a resin material, and the shaft 8, the iron core 17, the plurality of magnets 20, and the block 197 are fixed together using the connecting member 19.

[0052] The manufacturing method of the rotor 3 of the electric motor 1 allows the magnet 20 to be positioned in the circumferential direction by the abutment surface 201 of the block 197 arranged in the cutout 195. The rotor 3 of the electric motor 1 can easily be positioned in the circumferential direction by pressing the abutment surface 201, which is the abutment surface of the block 197, against the side end surface 21 of the magnet 20 at the portion of the cutout 195 in the outer circumferential portion 191 during integral molding. Therefore, the rotor 3 of the electric motor 1 does not need to be provided with a positioning mechanism for the magnet 20 on the iron core 17, and the position of the magnet 20 in the circumferential direction can be specified. When the rotor 3 has the block 197, the number of parts increases compared to when positioning is performed using a mold 210 for integral molding such as the positioning member 200. However, this is effective when it is desired to reduce manufacturing costs because rotors 3 for multiple models, such as rotors 3 with different pole numbers, can be molded using the same mold.

[0053] The electric motor 1 also includes the rotor 3 of the electric motor 1 configured as described above, and the stator 2 provided to face the outer peripheral surfaces of the plurality of magnets 20. The electric motor 1 includes the rotor 3 configured as described above, and therefore can achieve the same effects as the rotor 3 described above.

[0054] Embodiment 2. Figure 8 is a perspective view showing the relationship between the magnets 20 and the connecting member 19 in the rotor 3 according to embodiment 2. Figure 8 shows part A in Figure 2 as an example. Figure 9 is a side view of the cutout 195 in the rotor 3 according to embodiment 2. Figure 9 is a side view of the rotor 3 as seen from the direction of the white arrow in Figure 8, and is a side view of part B of the rotor 3 as seen from the circumferential direction. The relationship between the magnets 20 and the connecting member 19 in the rotor 3 according to embodiment 2 will be explained using Figures 8 and 9. The rotor 3 according to embodiment 2 has the same configuration as the rotor 3 according to embodiment 1 except for the configuration described below. Components having the same functions and actions as those in embodiment 1 are designated by the same reference numerals, and their explanation will be omitted.

[0055] In the rotor 3 according to the second embodiment, at least one of the above-described notches 195 is provided in a portion that corresponds to one or more corners of the rectangular-shaped plurality of magnets 20 when viewed in a radial direction perpendicular to the axial direction of the shaft 8. In the rotor 3 shown in FIG. 8 , the notches 195 are formed in two corners of the magnet 20 in the upward direction of the page. The positions where the notches 195 are formed are not limited to the two upper corners of the magnet 20. The notches 195 may be formed in any position that corresponds to one or more of the four corners of the rectangular-shaped plurality of magnets 20.

[0056] In each of the plurality of magnets 20 in the rotor 3 according to the second embodiment, an axial end face 22, which is an end face in a direction parallel to the axial direction of the shaft 8, is exposed from the connecting member 19 in at least one or more cutouts 195. As described above, in each of the plurality of magnets 20, a portion of a side end face 21, which is an end face in the circumferential direction, is exposed from the connecting member 19 in at least one or more cutouts 195. That is, in the rotor 3 according to the second embodiment, cutouts 195 are formed at positions corresponding to one or more corner portions of the magnet 20, and the side end face 21 and the axial end face 22 of the magnet 20 are exposed from the connecting member 19 in the cutouts 195.

[0057] [Operation and Effects of Rotor 3 and Motor 1] In the rotor 3 according to the second embodiment, at least one notch 195 is provided in a portion corresponding to one or more corners of the plurality of magnets 20 when viewed in a radial direction perpendicular to the axial direction of the shaft 8. In the rotor 3L according to the comparative example shown in FIG. 7 , the corners of the magnets 20 are covered with resin. In such a rotor 3L, centrifugal force or magnetic attraction is applied to the resin covering the corners of the magnets 20 during operation of the motor, causing stress to concentrate in the resin, which may result in damage to the resin. In the rotor 3 according to the second embodiment, the provision of notches 195 in the resin at the corners of the magnets 20 can alleviate stress concentration, thereby ensuring the strength of the connecting members 19 and improving the strength of the rotor 3.

[0058] Furthermore, in the rotor 3 according to the second embodiment, each of the plurality of magnets 20 has an exposed axial end face 22, which is the end face in a direction parallel to the axial direction of the shaft 8, in at least one or more cutouts 195. In the rotor 3 of the electric motor 1, the magnet 20 can be easily positioned in the axial direction by pressing the contact surface of a positioning member 200, which is integrated with the mold 210 for integral molding, against the axial end face 22 of the magnet 20 in the portion where the cutout 195 is formed during integral molding. Therefore, the rotor 3 of the electric motor 1 does not need to provide a magnet 20 positioning mechanism in the iron core 17, and the position of the magnet 20 in the axial direction can be specified. In the rotor according to the second embodiment, the magnet 20 can be positioned both circumferentially and axially in the cutouts 195.

[0059] The electric motor 1 also includes the rotor 3 of the electric motor 1 configured as described above, and the stator 2 provided to face the outer peripheral surfaces of the plurality of magnets 20. The electric motor 1 includes the rotor 3 configured as described above, and therefore can achieve the same effects as the rotor 3 described above.

[0060] Furthermore, since the rotor 3 according to the second embodiment has the same configuration as the rotor 3 according to the first embodiment, it can achieve the same effects as the rotor 3 according to the first embodiment.

[0061] Embodiment 3. Fig. 10 is a conceptual diagram showing a cross section of a rotor 3 according to embodiment 3 along the axial and radial directions. Fig. 11 is a conceptual diagram showing part C of Fig. 10 of the rotor 3 according to embodiment 3. Fig. 10 conceptually shows the internal structure of the rotor 3 according to embodiment 3. Fig. 11 shows the positional relationship between the connecting member 19, the magnet 20, and the iron core 17. The relationship between the magnet 20, the connecting member 19, and the iron core 17 of the rotor 3 according to embodiment 3 will be explained using Figs. 10 and 11. Note that the rotor 3 according to embodiment 3 has the same configuration as the rotor 3 according to embodiment 1 or embodiment 2 except for the configuration described below. Components having the same functions and actions as those of embodiment 1 and embodiment 2 are designated by the same reference numerals, and their explanation will be omitted.

[0062] As shown in Fig. 11 , the magnets 20 are exposed from the connecting member 19 at the cutouts 195. The rotor 3 has magnet exposed portions 25, which are the portions of the magnets 20 exposed from the connecting member 19 at the cutouts 195. The connecting member 19 has resin end faces 196, which are the axial end faces of the connecting member 19 at the cutouts 195. In Fig. 11 , resin end face position T1 indicates the position of the resin end face 196, which is the axial end face of the connecting member 19 at the cutouts 195.

[0063] The iron core 17 has an iron core end face 17a which is the axial end face of the iron core 17. In Fig. 11, an iron core end face position T2 indicates the position of the iron core end face 17a which is the axial end face of the iron core 17. The axial direction is the direction parallel to the axial direction of the shaft 8.

[0064] 10 , the rotor 3 is configured such that each of the multiple magnets 20 is larger than the iron core 17 in the direction parallel to the axial direction of the shaft 8. The resin end face 196 of the cutout 195 is configured to be closer to the axial end face 22 than the iron core end face 17a, which is the end face of the iron core 17 in the direction parallel to the axial direction. The resin end face 196 is the end face of the connecting member 19, and is the end face in the direction parallel to the axial direction of the shaft 8 of at least one or more cutouts 195. In other words, the rotor 3 is formed such that the resin end face position T1 is closer to the axial end face 22 of the magnet 20 than the iron core end face position T2 in the direction parallel to the axial direction of the shaft 8.

[0065] Figure 12 is a side view of the cutout 195 of the rotor 3 according to embodiment 3. Figure 12 is a side view of the rotor 3 as viewed from the circumferential direction. The magnet 20 has a magnet corner 26 exposed from the cutout 195. The magnet corner 26 may be formed in an R-shape with a rounded corner portion, or may be formed in a tapered shape with an inclined surface.

[0066] [Operation and Effects of Rotor 3 and Motor 1] In rotor 3 according to embodiment 3, each of the multiple magnets 20 is configured to be larger than iron core 17 in the direction parallel to the axial direction of shaft 8. Resin end face 196 of cutout 195 is configured to be located closer to shaft end face 22 than iron core end face 17a, which is the end face of iron core 17 in the direction parallel to the axial direction. Resin end face 196 is the end face of at least one or more cutouts 195 in the direction parallel to the axial direction of shaft 8. With the above configuration, rotor 3 can ensure strength by increasing the thickness of the resin in connecting member 19 at locations where stress is likely to concentrate.

[0067] FIG. 13 is a conceptual diagram showing portion C of FIG. 10 of a rotor 3R according to a comparative example. The rotor 3R according to the comparative example is configured so that the core end face 17a of the core 17 is closer to the axial end face 22 than the resin end face 196 in the cutout 195. That is, the rotor 3 is configured so that the resin end face position T1 is farther from the axial end face 22 of the magnet 20 than the core end face position T2 in a direction parallel to the axial direction of the shaft 8. In this case, the thickness of the resin between the exposed magnet portion 25 of the magnet 20 and the core 17 of the rotor 3R according to the comparative example is thinner than that of the rotor 3 shown in the third embodiment of FIG. 11, as indicated by arrow D in FIG. 13. The thickness of the resin between the exposed magnet portion 25 of the magnet 20 and the core 17 of the rotor 3R according to the comparative example is thin, as indicated by arrow D in FIG. 13, making it difficult to ensure strength.

[0068] The rotor 3 according to the third embodiment is configured so that the resin end surface 196 of the cutout 195 is located closer to the shaft end surface 22 than the core end surface 17a. Therefore, the rotor 3 according to the third embodiment can increase the thickness of the resin at the location where stress is likely to concentrate in the connecting member 19 compared to the rotor 3R according to the comparative example in which the core end surface 17a is located closer to the shaft end surface 22 than the resin end surface 196. As a result, the rotor 3 according to the third embodiment can have improved strength compared to the rotor 3R according to the comparative example.

[0069] The electric motor 1 also includes the rotor 3 of the electric motor 1 configured as described above, and the stator 2 provided to face the outer peripheral surfaces of the plurality of magnets 20. The electric motor 1 includes the rotor 3 configured as described above, and therefore can achieve the same effects as the rotor 3 described above.

[0070] Furthermore, since the rotor 3 according to embodiment 3 has the same configuration as the rotor 3 according to embodiments 1 and 2, it can achieve the same effects as the rotor 3 according to embodiments 1 and 2.

[0071] 1 Electric motor, 2 Stator, 3 Rotor, 3L rotor, 3R rotor, 5 Motor housing, 6 Casing, 7 Bearing housing, 8 Shaft, 9a Bearing, 9b Bearing, 10 Sheet metal cover, 11 Bracket cover, 12 Printed circuit board, 13 Board holder, 16 Bottom wall portion, 17 Iron core, 17a Iron core end face, 19 Connecting member, 19a Outer periphery, 20 Magnet, 21 Side end face, 22 Shaft end face, 25 Magnet exposed portion, 26 Magnet corner portion, 191 Outer periphery, 192 Middle portion, 192a Rib, 193 Inner periphery, 195 Notch portion, 196 Resin end face, 197 Block, 200 Positioning member, 200a Positioning member, 201 Contact surface portion, 210 Mold.

Claims

1. A shaft and a cylindrical iron core provided on the outer periphery of the shaft; a plurality of magnets formed in a rectangular plate shape, the magnets being arranged on the outer circumferential side of the iron core in a direction parallel to the circumferential direction of the shaft and facing the iron core in a radial direction perpendicular to the axial direction of the shaft; a cylindrical resin connecting member to which the shaft, the iron core, and the plurality of magnets are fixed; Equipped with the shaft, the iron core, the plurality of magnets, and the connecting member are integrally molded, Each of the plurality of magnets is configured to be larger than the iron core in a direction parallel to the axial direction, The connecting member is the connecting member is formed so as to cover edge portions of the plurality of magnets, and has at least one or more notches recessed from the outer circumferential surface of the connecting member in each portion between two adjacent magnets of the plurality of magnets in a direction parallel to the circumferential direction of the shaft, Each of the plurality of magnets is In the at least one notch portion, a part of a side end surface, which is an end surface in the circumferential direction, is exposed from the connecting member, The at least one cutout portion is When viewed in the radial direction perpendicular to the axial direction of the shaft, the magnets are provided at portions corresponding to one or more corners of the plurality of magnets, Each of the plurality of magnets is In the at least one notch portion, an axial end surface that is an end surface in a direction parallel to the axial direction is exposed, A rotor of an electric motor configured such that the resin end face, which is the end face in a direction parallel to the axial direction of at least one of the notches, is located closer to the axial end face than the iron core end face, which is the end face of the iron core in a direction parallel to the axial direction.

2. The connecting member is a cylindrical outer circumferential portion that fixes the iron core and the plurality of magnets; a cylindrical inner peripheral portion to which the shaft is fixed; an intermediate portion that connects the outer circumferential portion and the inner circumferential portion; and The rotor of the electric motor according to claim 1 , wherein the at least one notch is formed in the outer periphery.

3. The connecting member is 3. The rotor of claim 1, wherein a block having a melting point higher than that of the connecting member is disposed in the at least one notch.

4. The rotor of the electric motor according to claim 1 or 2; a stator provided to face outer peripheral surfaces of the plurality of magnets; An electric motor equipped with

5. A method for manufacturing a rotor for an electric motor according to claim 1 or 2, a member placement process in which the shaft serving as a rotation axis, the iron core formed cylindrically on the outer periphery of the shaft, and the plurality of magnets facing the iron core on the outer periphery of the iron core are placed in an integral molding die, and the plurality of magnets are positioned by abutting a contact surface portion that becomes part of the die against each side end surface of the plurality of magnets in a portion between two adjacent magnets of the plurality of magnets in a direction parallel to the circumferential direction of the shaft; an integral molding process in which the shaft, the iron core, and the plurality of magnets are integrally molded using a resin material, and the shaft, the iron core, and the plurality of magnets are fixed by the connecting member; a die removing step in which the die is removed from the integrally molded product of the shaft, the iron core, the plurality of magnets, and the connecting member, and at least one or more notches recessed in the arrangement direction of the shaft are formed on the outer circumferential surface of the connecting member at the position of the abutment surface portion of the connecting member; A method for manufacturing a rotor for an electric motor having the above structure.

6. A method for manufacturing a rotor for an electric motor according to claim 3, comprising the steps of: a member placement process in which the shaft serving as a rotation axis, the iron core formed in a cylindrical shape on the outer periphery of the shaft, the plurality of magnets facing the iron core on the outer periphery of the iron core, and the block having a melting point higher than that of the connecting member are placed in an integral molding die, and the plurality of magnets are positioned by abutting the block against each side end face of the plurality of magnets in each portion between two adjacent magnets in a direction parallel to the circumferential direction of the shaft; an integral molding process in which the shaft, the iron core, the plurality of magnets, and the block are integrally molded using a resin material, and the shaft, the iron core, the plurality of magnets, and the block are fixed together using the connecting member; A method for manufacturing a rotor for an electric motor having the above structure.