Rotor, motor, blower, air-conditioning device, and method for manufacturing rotor

Abstract

A rotor according to the present disclosure comprises: a shaft; an annular rotor core that is fixed to the shaft, the annular rotor core having a magnet hole and surrounding the shaft from the outer side in the radial direction of the shaft; a bond magnet provided in the magnet hole; and a first resin part provided to an end surface of the rotor core in the axial direction of the shaft. A gate mark is formed on an axial end surface of the bond magnet, and the first resin part covers the gate mark of the bond magnet.

Description

Rotor, motor, blower, air conditioner, and method of manufacturing rotor

[0001] The present disclosure relates to a rotor, a motor, a blower, an air conditioner, and a method for manufacturing a rotor.

[0002] Conventionally, rotors with bonded magnets in their rotor cores have been known. Bonded magnets are formed by filling magnet holes formed in the rotor core with resin mixed with magnetic powder (see, for example, Patent Document 1).

[0003] JP 2018-19524 A (see abstract)

[0004] Gate marks remain on the axial end face of the bonded magnet at positions corresponding to the gates of the mold. If the resin pieces that make up the gate marks break off and fall off the rotor, they can become trapped between the rotor and stator, causing motor malfunctions.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to prevent resin pieces that form gate marks from falling off from a rotor.

[0006] The rotor of the present disclosure includes a shaft, an annular rotor core fixed to the shaft, having magnet holes and surrounding the shaft from the outside in the radial direction, bonded magnets provided in the magnet holes, and a first resin portion provided on an end face of the rotor core in the axial direction of the shaft. A gate mark is formed on the axial end face of the bonded magnet, and the first resin portion covers the gate mark of the bonded magnet.

[0007] According to the present disclosure, the first resin portion covers the gate marks of the bonded magnet, thereby preventing the resin pieces that make up the gate marks from falling off the rotor.

[0008] 10 is a longitudinal cross-sectional view showing a motor according to a first embodiment. FIG. 11 is a cross-sectional view showing a motor according to the first embodiment. FIG. 12 is a cross-sectional view showing a rotor according to the first embodiment. FIG. 13 is a plan view (A) and a longitudinal cross-sectional view (B) showing a rotor according to the first embodiment. FIG. 14 is a longitudinal cross-sectional view showing a rotor and a stator according to the first embodiment. FIG. 15 is a flowchart showing a manufacturing process of the rotor according to the first embodiment. FIG. 16 is a longitudinal cross-sectional view showing a mold for molding the bonded magnet according to the first embodiment. FIG. 17 is a longitudinal cross-sectional view showing a state in which the bonded magnet has been molded using the mold of FIG. 8. FIG. 18 is a longitudinal cross-sectional view showing a mold for molding the first resin portion according to the first embodiment. FIG. 19 is a longitudinal cross-sectional view (A) and a bottom view (B) showing a rotor according to a second embodiment. FIG. 19 is a flowchart showing a manufacturing process of the rotor according to the second embodiment. FIG. 11 is a longitudinal cross-sectional view showing a mold for molding the first resin portion according to the second embodiment. FIG. 12 is a longitudinal cross-sectional view showing a motor according to the second embodiment. FIG. 13 is a plan view (A) and a longitudinal cross-sectional view (B) showing a rotor according to a third embodiment. FIG. 14 is a plan view (A) and a longitudinal cross-sectional view (B) showing a rotor according to a fourth embodiment. Fig. 10 is a plan view (A) and a longitudinal cross-sectional view (B) showing a rotor of embodiment 5. Fig. 11 is a cross-sectional view showing a rotor of embodiment 6. Fig. 12 is a cross-sectional view showing a rotor of embodiment 7. Fig. 13 is a plan view (A) and a longitudinal cross-sectional view (B) showing a rotor of embodiment 7. Fig. 14 is a diagram showing an air conditioner to which the motors of each embodiment can be applied, and Fig. 15 is a diagram showing an outdoor unit of the air conditioner.

[0009] Embodiment 1. <Overall Configuration of Motor 1> A motor according to embodiment 1 will now be described. Fig. 1 is a longitudinal cross-sectional view showing motor 1 according to embodiment 1. Motor 1 is a permanent magnet synchronous motor, and is used, for example, in a blower of an air conditioning device 500 (Fig. 21(A)).

[0010] The motor 1 includes a rotor 2 having a shaft 10, and a stator 5 surrounding the rotor 2. The motor 1 also includes bearings 91 and 92 that support the shaft 10, and a molded resin part 60 that covers the stator 5. The central axis Ax of the shaft 10 defines the center of rotation of the rotor 2. The stator 5 and the molded resin part 60 constitute a molded stator 6.

[0011] Hereinafter, the direction of the central axis Ax will be referred to as the "axial direction." The radial direction centered on the central axis Ax will be referred to as the "radial direction." The circumferential direction centered on the central axis Ax will be referred to as the "circumferential direction." Furthermore, a cross-sectional view taken along a plane perpendicular to the central axis Ax will be referred to as a "transverse cross-sectional view," and a cross-sectional view taken along a plane parallel to the central axis Ax will be referred to as a "longitudinal cross-sectional view."

[0012] The shaft 10 protrudes from the molded stator 6 to one side in the axial direction. For example, an impeller 511 of a blower (FIG. 21(B)) is attached to the tip 101 of the shaft 10 on the protruding side. Therefore, the side from which the shaft 10 protrudes is referred to as the "load side," and the opposite side is referred to as the "anti-load side."

[0013] <Configuration of molded stator 6> As described above, the molded stator 6 includes the stator 5 and the molded resin portion 60. The molded resin portion 60 is formed of a thermosetting resin such as an unsaturated polyester resin or an epoxy resin. The unsaturated polyester resin is, for example, a bulk molding compound (BMC).

[0014] The molded resin part 60 is an outer shell member that covers the radially outer side and the anti-load side of the stator 5. The molded resin part 60 has an opening 61 on the load side and a bottom 62 on the anti-load side. The rotor 2 is inserted into the inside of the stator 5 through the opening 61.

[0015] A metal bracket 93 that supports the load-side bearing 91 is attached to the opening 61 of the molded resin part 60. The bracket 93 is an annular member that holds the bearing 91 at its radial center. A bottom 62 of the molded resin part 60 is formed to cover the anti-load side of the stator 5. A recess 63 that houses the anti-load side bearing 92 is formed in the bottom 62.

[0016] A circuit board 65 is disposed on the anti-load side of the stator 5. The circuit board 65 is annular and held by the molded resin part 60. Elements 66 such as a drive circuit are mounted on the circuit board 65, and lead wires 67 are wired to the circuit board 65. The lead wires 67 are drawn out from lead-out parts 68 provided on the outer periphery of the molded resin part 60.

[0017] The outer casing member covering the stator 5 and the circuit board 65 is not limited to the molded resin part 60, but may be, for example, a metal shell. In this case, the stator core 50 can be fixed to the shell by shrink fitting or the like. The circuit board 65 may also be provided separately from the motor 1.

[0018] Fig. 2 is a cross-sectional view showing the motor 1. The molded resin portion 60 is omitted in Fig. 2. The stator 5 has a stator core 50, a coil 55 wound around the stator core 50, and an insulating portion 54 provided therebetween.

[0019] The stator core 50 is a laminated body formed by stacking multiple magnetic core sheets in the axial direction. The core sheets are thin plates primarily composed of iron, more specifically, electromagnetic steel sheets. The thickness of the core sheets is, for example, 0.2 mm to 0.5 mm. Instead of a laminated body of core sheets, a processed block primarily composed of iron may be used.

[0020] The stator core 50 has an annular yoke 51 and a plurality of teeth 52 extending radially inward from the yoke 51. The number of teeth 52 is 12 in this example, but is not limited to this. Tips 52a that face the rotor 2 are formed at the tips of the teeth 52.

[0021] A slot 53 is formed between circumferentially adjacent teeth 52. Coils 55 are wound around teeth 52 with insulating portions 54 interposed therebetween and housed in slots 53.

[0022] The insulating portion 54 is made of insulating resin such as PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), or liquid crystal polymer (LCP). An insulating film may also be provided to cover the inner surface of the slot 53. The insulating film is made of PET (polyethylene terephthalate), for example, and has a thickness of 0.035 to 0.4 mm.

[0023] The coils 55 are wound around the teeth 52 and housed in the slots 53. The coils 55 have a conductor, such as a copper wire or an aluminum wire, and an insulating coating covering the conductor. The coils 55 may be wound by either concentrated winding or distributed winding.

[0024] <Configuration of Rotor 2> Fig. 3 is a cross-sectional view showing the rotor 2. As shown in Fig. 3, the rotor 2 has a rotor core 20 fixed to the shaft 10 and a bonded magnet 30 provided in the rotor core 20.

[0025] The rotor core 20 is an annular member centered on the central axis Ax, and has an outer periphery 20a and an inner periphery 20b. The rotor core 20 is a laminate formed by stacking a plurality of magnetic core sheets in the axial direction. The core sheets are thin plates containing Fe as a main component, and more specifically, electromagnetic steel sheets. The thickness of the core sheets is, for example, 0.2 mm to 0.5 mm.

[0026] The rotor core 20 has a plurality of magnet holes 21 in the circumferential direction. The magnet holes 21 are arranged at equal intervals in the circumferential direction and at equal distances from the central axis Ax. The magnet holes 21 also penetrate the rotor core 20 in the axial direction. The number of magnet holes 21 is 10 here, but may be two or more.

[0027] Each magnet hole 21 is provided with one bonded magnet 30. A bonded magnet is a magnet made by mixing magnetic powder and resin, molding it, and solidifying it.

[0028] The bonded magnet 30 is preferably a rare earth bonded magnet. The rare earth magnet may be, for example, a neodymium magnet containing Nd (neodymium), Fe (iron), and B (boron), or a samarium-iron-nitrogen magnet containing Sm (samarium), Fe, and N (nitrogen). Alternatively, a ferrite bonded magnet may be used instead of a rare earth bonded magnet. The resin for the bonded magnet may be, for example, nylon, PPS, or epoxy resin.

[0029] In rotor 2, one bonded magnet 30 constitutes one magnetic pole. The number of poles in rotor 2 is 10 here, but may be two or more. A radial line passing through the circumferential center of bonded magnet 30 is defined as a pole center line CL. The intersection of pole center line CL and outer periphery 20a of rotor core 20 defines a pole center P of rotor 2.

[0030] Bonded magnet 30 has a shape in which its circumferential center protrudes radially inward (i.e., toward central axis Ax), i.e., a curved shape that is convex radially inward. More specifically, bonded magnet 30 has, for example, an arc-shaped cross section in a plane perpendicular to the axial direction.

[0031] The cross-sectional shape of bonded magnet 30 is not limited to an arc shape, and may be, for example, rectangular, U-shaped, or V-shaped. In order to increase the area of ​​magnetic pole faces 30a, 30b of bonded magnet 30, it is desirable for bonded magnet 30 to have a curved shape that is convex radially inward.

[0032] Bonded magnet 30 has a magnetic pole face 30a facing the pole center P, a magnetic pole face 30b on the opposite side, and an end face portion 30c facing the outer periphery 20a of rotor core 20. Magnetic pole face 30a is, for example, a north pole, and magnetic pole face 30b is, for example, a south pole, although the opposite is also possible. Magnetic pole face 30a is also referred to as a first magnetic pole face, and magnetic pole face 30b is also referred to as a second magnetic pole face.

[0033] Gate mark 31 is formed at the circumferential center (i.e., on pole center line CL) of bonded magnet 30. Gate mark 31 is formed at a position corresponding to gate 73a of mold 70 in the molding process of bonded magnet 30 (FIGS. 6 and 7), which will be described later. Gate mark 31 may be a recessed or protruding portion.

[0034] As will be described later, bonded magnet 30 is molded by injecting resin into magnet hole 21 of rotor core 20. Therefore, the cross-sectional shape of magnet hole 21 in a plane perpendicular to the axial direction is the same as the cross-sectional shape of bonded magnet 30.

[0035] As shown in Fig. 2, the outer periphery 20a and inner periphery 20b of the rotor core 20 are, for example, circular about the central axis Ax, but they do not necessarily have to be circular. The shaft 10 is fixed to the inner periphery 20b of the rotor core 20 by press fitting or the like. The shaft 10 is formed of a metal such as carbon steel for mechanical structures (S45C). A resin portion may be provided between the shaft 10 and the inner periphery 20b of the rotor core 20, which will be described in the second embodiment.

[0036] Fig. 4(A) is a plan view showing the rotor 2. Fig. 4(B) is a cross-sectional view of the rotor 2 taken along line 4B-4B in Fig. 4(A). As shown in Figs. 4(A) and 4(B), the rotor core 20 has a first end face 20c which is one end face in the axial direction, and a second end face 20d which is the other end face in the axial direction.

[0037] The rotor 2 has a first resin portion 11 that covers the first end face 20c of the rotor core 20. The first resin portion 11 is formed of an engineering plastic or super engineering plastic that has excellent heat resistance. More specifically, the first resin portion 11 is formed of a thermoplastic resin such as PBT, PA (polyamide), PEEK (polyether ether ketone), or LCP.

[0038] The first resin portion 11 has an outer periphery 11a and an inner periphery 11b. The outer periphery 11a and the inner periphery 11b are, for example, circular and centered on the central axis Ax, but they do not necessarily have to be circular. The inner periphery 11b is in contact with the shaft 10. The axial thickness of the first resin portion 11 is preferably 0.5 mm or more and 10 mm or less.

[0039] First resin portion 11 is formed so as to cover at least a portion of bonded magnet 30. In other words, first resin portion 11 has the effect of regulating the axial position of bonded magnet 30 within magnet hole 21.

[0040] 4(B), distance R1 from central axis Ax to outer periphery 11a of first resin portion 11 and distance R2 from central axis Ax to gate mark 31 satisfy R1>R2. In other words, first resin portion 11 is provided so as to cover gate mark 31 of bonded magnet 30. In other words, first resin portion 11 is provided so as to overlap gate mark 31 of bonded magnet 30 in the axial direction.

[0041] Furthermore, a distance R1 from the central axis Ax to the outer periphery 11 a of the first resin portion 11 and a distance R3 from the central axis Ax to the outer periphery 20 a of the rotor core 20 satisfy R1 < R3. In other words, the outer periphery 11 a of the first resin portion 11 is located radially inward of the outer periphery 20 a of the rotor core 20.

[0042] When the gate mark 31 is a recess, it is desirable that the first resin part 11 penetrates into the gate mark 31. When the gate mark 31 is a protrusion, it is desirable that the first resin part 11 surrounds the gate mark 31 from the periphery.

[0043] The size of gate mark 31, i.e., the size in a plane perpendicular to the axial direction (here, the outer diameter), is, for example, 1 mm. The size of gate mark 31 is not limited to 1 mm, and may be any size that allows stable molding of bonded magnet 30.

[0044] Fig. 5 is a longitudinal cross-sectional view showing the rotor 2 and the stator 5. Note that the insulating portion 54 and the coils 55 of the stator 5 are omitted in Fig. 5. As shown in Fig. 5, the axial length L1 of the rotor core 20 is longer than the axial length L2 of the stator core 50.

[0045] Rotor core 20 protrudes in the axial direction from stator core 50. Bond magnets 30 provided in magnet holes 21 of rotor core 20 also protrude in the axial direction from stator core 50. Here, rotor core 20 and bond magnets 30 protrude on both axial sides of stator core 50, but they may also protrude on only one axial side.

[0046] Gate mark 31 is formed at one axial end of bond magnet 30. Therefore, gate mark 31 protrudes in the axial direction further than stator core 50. In other words, gate mark 31 is located axially outward from the axial end face of stator core 50.

[0047] <Method of Manufacturing the Motor> Next, a method of manufacturing the motor 1 will be described. Fig. 6 is a flowchart showing the manufacturing process of the motor 1.

[0048] In step S101, core sheets such as electromagnetic steel sheets are stacked and fixed by caulking or the like to form the rotor core 20.

[0049] In step S102, rotor core 20 is placed in mold 70 (FIG. 7) which serves as a first mold used to mold bonded magnet 30. Bonded magnet 30 is molded by, for example, injection molding.

[0050] 7 is a cross-sectional view showing a mold 70 used to mold bonded magnet 30. Mold 70 has a lower mold 71 and an upper mold 72. Upper mold 72 is provided so as to be movable relative to lower mold 71. Lower mold 71 has an accommodating portion 71a which is a cylindrical recess that accommodates rotor core 20, and a center core portion 71b that fits into the inner periphery of rotor core 20.

[0051] The upper mold 72 has a supply path 73 that supplies molten material to the accommodation portion 71a of the lower mold 71. The supply path 73 has a sprue 73c that is connected to a nozzle at the upper end of the upper mold 72, a plurality of runners 73b that branch off and extend from the sprue 73c, and gates 73a that extend from each runner 73b to the molding space.

[0052] The number of gates 73a is the same as the number of bond magnets 30 of the motor 1. The gates 73a are arranged equidistant from the central axis Ax and at equal intervals in the circumferential direction. The positions of the gates 73a coincide with the circumferential centers of the magnet holes 21 of the rotor core 20 accommodated in the accommodation portion 71a of the lower mold 71.

[0053] The upper die 72 is raised to open the accommodation portion 71a of the lower die 71, and the rotor core 20 is accommodated in the accommodation portion 71a of the lower die 71. Next, the upper die 72 is lowered to clamp the lower die 71 and the upper die 72 together.

[0054] In step S103, the material of bond magnet 30 is filled into magnet hole 21 of rotor core 20 to form a compact, which is a precursor of bond magnet 30. Specifically, molten resin obtained by melting resin powder at high temperature and mixing it with magnetic powder is supplied from a nozzle to sprue 73c of mold 70.

[0055] The molten resin supplied to the sprue 73c flows through the runner 73b to the gate 73a. The gate 73a faces the magnet holes 21 of the rotor core 20 arranged in the housing portion 71a, and the molten resin is filled into the magnet holes 21 from the gate 73a.

[0056] After the molten resin is filled into magnet holes 21 of rotor core 20, lower die 71 and upper die 72 are cooled, whereby the molten resin hardens and a compact, which is the precursor of bond magnet 30, is formed.

[0057] 8, the upper die 72 is raised to open the accommodation portion 71a of the lower die 71, and the rotor core 20 is removed from the accommodation portion 71a. At this time, a gate mark 31 is formed on the upper end surface of the compact at a position opposite the gate 73a, as indicated by the symbol B.

[0058] In step S104, the rotor core 20 and the shaft 10 are fixed together. The shaft 10 is fixed to the inner periphery 20b of the rotor core 20 by press-fitting, caulking, or the like. The rotor core 20 and the shaft 10 may be integrally molded using a resin such as an unsaturated polyester resin.

[0059] In step S105, the rotor core 20 and the shaft 10 are placed in a mold 80 (FIG. 9) that serves as a second mold used to mold the first resin portion 11. The first resin portion 11 is molded by, for example, injection molding.

[0060] 9 is a cross-sectional view showing a mold 80 used to mold the first resin portion 11. The mold 80 has a lower mold 81 and an upper mold 82. The upper mold 82 is provided so as to be movable relative to the lower mold 81. The lower mold 81 has a cylindrical housing portion 81a that houses the rotor core 20, and a hole 81b that accommodates the lower end of the shaft 10. The hole 81b is formed at the radial center of the housing portion 81a.

[0061] The upper mold 82 has a recess 82a facing the accommodation portion 81a, a hole 82b that accommodates the upper end of the shaft 10, and a supply path 83 that supplies molten material to the recess 82a. The recess 82a is used to form a hollow portion H1 for molding the first resin portion 11. The hole 82b is formed at the radial center of the recess 82a.

[0062] The supply path 83 has a sprue 83c connected to a nozzle (not shown) at the upper end of the upper mold 82, a plurality of runners 83b branching off and extending from the sprue 83c, and a gate 83a extending from each runner 83b to the recess 82a.

[0063] The number of gates 83a is four, and they are arranged equidistant from the central axis Ax and at equal intervals in the circumferential direction. The number of gates 83a is not limited to four, but may be two or more. The gates 83a are located radially inward of the magnet holes 21 of the rotor core 20.

[0064] The upper die 82 is raised to open the accommodation portion 81 a of the lower die 81, and the rotor core 20 is accommodated in the accommodation portion 81 a of the lower die 81, and the shaft 10 is accommodated in the hole portion 81 b. In this state, a hollow portion H1 for forming the first resin portion 11 is formed in the recess 82 a of the upper die 82, and the first end surface 20 c of the rotor core 20 faces this hollow portion H1.

[0065] In step S106, the molten resin, which is the material of the first resin portion 11, is filled into the recess 82a from the supply path 83. The molten resin passes through the sprue 83c, the runner 83b, and the gate 83a and fills the hollow portion H1 in the recess 82a.

[0066] Thereafter, the lower mold 81 and the upper mold 82 are cooled, whereby the molten resin in the cavity H1 hardens and the first resin portion 11 is molded. The first resin portion 11 is formed so as to cover the gate mark 31 on the first end face 20c of the rotor core 20. The inner periphery 11b of the first resin portion 11 is formed so as to contact the shaft 10.

[0067] In step S107, the compacts in magnet holes 21 of rotor core 20 are magnetized using, for example, a magnetizing yoke. The magnetized compacts become bonded magnets 30. In this way, rotor 2 is completed.

[0068] In parallel with steps S101 to S107, the stator 5 is manufactured. First, core sheets such as electromagnetic steel sheets are stacked in the axial direction to assemble the stator core 50. Next, the insulating portion 54 is attached to the stator core 50, and the coil 55 is wound around the stator core 50 with the insulating portion 54 interposed therebetween.

[0069] Next, the stator 5 and the circuit board 65 are placed in a third mold for the molded stator 6, and a molding resin such as BMC is poured into the mold and heated. In other words, molding is performed. This completes the molded stator 6 in which the stator 5 and the circuit board 65 are covered with the molding resin part 60.

[0070] Thereafter, bearings 91 and 92 are attached to shaft 10 of rotor 2, and the rotor is inserted into stator 5 of molded stator 6. Bracket 93 is attached to opening 61 of molded stator 6, and cap 14 is attached to shaft 10. This completes motor 1 shown in FIG. 1. Note that if stator 5 is attached to a shell or the like without using molded resin portion 60, the molding process can be omitted.

[0071] <Function> Next, the function of embodiment 1 will be explained. Permanent magnets are classified into sintered magnets and bonded magnets. Bonded magnets have a lower magnetic force than sintered magnets, but offer greater freedom in terms of shape. In embodiment 1, bonded magnet 30 is formed in an arc shape, and the area of ​​pole faces 30a, 30b is large relative to the circumferential width of bonded magnet 30 (i.e., the width of one magnetic pole). This increases the amount of magnetic flux emanating from or flowing into bonded magnet 30, thereby increasing the magnetic force.

[0072] 8, in the molding process of bonded magnet 30, gate mark 31 is formed on one axial end face of bonded magnet 30. Gate mark 31 may be a recess or a protrusion.

[0073] 10A and 10B are schematic diagrams illustrating two examples of gate marks 31. In the example shown in FIG. 10A, gate marks 31 are formed as recesses A. Burrs, which are tiny pieces of resin, are formed around recesses A. If the burrs break off and fall off from rotor 2 during rotation of rotor 2, the burrs may become caught in the gap between rotor 2 and stator 5, potentially causing a malfunction of motor 1.

[0074] 10B, the gate mark 31 is formed as a protrusion B. If the protrusion B breaks and falls off the rotor 2 while the rotor 2 is rotating, the resin piece that constitutes the protrusion B may become caught in the gap between the rotor 2 and the stator 5, possibly causing a malfunction of the motor 1.

[0075] Therefore, in the rotor 2 of the first embodiment, the first resin portion 11 is formed on the first end face 20c on the same side of the rotor core 20 as the gate mark 31. The first resin portion 11 is formed so as to cover the gate mark 31.

[0076] 10A , when the gate mark 31 is a recess A, the first resin portion 11 is formed to fit into the recess A. This makes it possible to prevent the burr from breaking around the recess A. Even if the burr breaks, the first resin portion 11 prevents the burr from moving, preventing the burr from falling off the rotor 2.

[0077] 10B , when the gate mark 31 is a protrusion B, the first resin portion 11 is formed to surround the protrusion B. This makes it possible to prevent the protrusion B from breaking. Even if the protrusion B breaks, the movement of the resin piece is prevented by the first resin portion 11, so that the resin piece can be prevented from falling off the rotor 2.

[0078] In this way, in rotor 2 of embodiment 1, first resin part 11 is formed to cover gate mark 31 of bond magnet 30, thereby preventing defects caused by resin pieces falling off from gate mark 31.

[0079] Note that gate marks are also formed in the first resin portion 11 at positions corresponding to the gates 83a (FIG. 9). However, because the first resin portion 11 does not contain magnetic powder, the material is strong and unlikely to fall off. Even if a resin piece from the gate mark in the first resin portion 11 falls off the rotor 2, because the resin piece does not contain magnetic powder, it will not be attracted to the rotor 2 or the stator 5, and the impact on the motor 1 will be negligible. The gate marks in the first resin portion 11 will be described in embodiment 7.

[0080] As explained with reference to Figure 4(B), distance R1 from central axis Ax to outer periphery 11a of first resin portion 11 and distance R2 from central axis Ax to gate mark 31 satisfy R1 > R2. That is, first resin portion 11 covers gate mark 31 of bonded magnet 30. In other words, first resin portion 11 overlaps gate mark 31 of bonded magnet 30 in the axial direction. Therefore, it is possible to prevent resin pieces at gate mark 31 from falling off rotor 2.

[0081] Furthermore, the distance R1 from the central axis Ax to the outer periphery 11a of the first resin portion 11 and the distance R3 from the central axis Ax to the outer periphery 20a of the rotor core 20 satisfy the relationship R1 < R3. That is, the outer periphery 11a of the first resin portion 11 is located radially inward of the outer periphery 20a of the rotor core 20. This prevents the first resin portion 11 from protruding radially outward beyond the rotor core 20 and affecting the rotation of the rotor 2. Furthermore, the amount of resin used in the first resin portion 11 can be kept small.

[0082] Furthermore, the first resin portion 11 is fixed to the rotor core 20 through contact with the first end face 20c of the rotor core 20, and is also fixed to the shaft 10 through contact between the inner periphery 11b of the first resin portion 11 and the shaft 10. This improves the integrity of the first resin portion 11 with the rotor core 20 and the shaft 10.

[0083] Furthermore, if the thickness of the first resin portion 11 is too thin, a large force is required to fill the molten resin in step S106 ( FIG. 6 ) described above. On the other hand, if the thickness of the first resin portion 11 is too thick, it takes time for the molten resin to cool and harden, resulting in a long cycle time. To simplify the manufacturing process and shorten the cycle time, it is desirable that the thickness of the first resin portion 11 be 0.5 mm or more and 10 mm or less. Within this thickness range, the amount of resin used in the first resin portion 11 can be kept small.

[0084] Furthermore, as shown in Figure 5, by making the axial length L1 of the rotor core 20 longer than the axial length L2 of the stator core 50, the amount of magnetic flux flowing from the rotor 2 to the stator 5 increases, thereby improving motor efficiency.

[0085] Furthermore, gate mark 31 is located at the circumferential center of bonded magnet 30. This is because gate 73a of mold 70 was located at the circumferential center of magnet hole 21 when bonded magnet 30 was molded. Therefore, the molten resin injected into magnet hole 21 from gate 73a spreads evenly to both sides of magnet hole 21 in the circumferential direction.

[0086] If the shape of bonded magnet 30 becomes asymmetric, the attractive force between rotor 2 and stator 5 will become uneven, which may result in vibration and noise. By positioning gate 73a at the circumferential center of magnet hole 21, bonded magnet 30 can be formed into a shape that is symmetrical in the circumferential direction. This makes it possible to suppress vibration and noise.

[0087] Furthermore, because the shape of gate marks 31 is prone to variation, there is a possibility that the shape of gate marks 31 will vary among the multiple bonded magnets 30 of rotor 2. When the shape of gate marks 31 varies in this way, the amount of magnetic flux flowing into stator core 50 will vary for each magnetic pole of rotor 2, which may result in vibration and noise.

[0088] 5 , in the first embodiment, gate marks 31 are located axially outward (indicated by arrow Z) from the axial end face of stator core 50. Since the magnetic flux flowing into stator core 50 from the portion of bond magnet 30 that protrudes axially from stator core 50 is relatively small, even if there is variation in the shape of gate marks 31 among multiple bond magnets 30 of rotor 2, the effect on the magnetic flux flowing into stator core 50 is small, and therefore vibration and noise can be suppressed.

[0089] Furthermore, since bond magnet 30 has a curved shape (e.g., an arc shape) that is convex radially inward, i.e., toward central axis Ax, the area of ​​pole faces 30a, 30b can be increased, thereby increasing the magnetic force.

[0090] Although the example in which the first resin portion 11 is molded integrally with the rotor core 20 has been described, the first resin portion 11 may be molded separately from the rotor core 20 and fixed to the shaft 10 by a method such as press fitting.

[0091] Effect of First Embodiment As described above, rotor 2 in the first embodiment has annular rotor core 20 having magnet holes 21, bond magnets 30 provided in magnet holes 21, and first resin portion 11 provided on first axial end face 20c of rotor core 20. Gate mark 31 is formed on one axial end face of bond magnet 30. First resin portion 11 is formed so as to cover gate mark 31 of bond magnet 30. Therefore, first resin portion 11 suppresses resin pieces of gate mark 31 from falling off rotor 2, and can prevent malfunctions of motor 1.

[0092] Embodiment 2. Fig. 11(A) is a longitudinal cross-sectional view showing a rotor 2A according to embodiment 2. Fig. 11(B) is a bottom view showing the rotor 2A according to embodiment 2. The rotor 2A according to embodiment 2 has a first resin portion 11 on the first end face 20c of the rotor core 20, and also a second resin portion 12 on the second end face 20d.

[0093] The second resin part 12 is preferably formed of the same resin as the first resin part 11. The second resin part 12 is formed of, for example, an engineering plastic having excellent heat resistance, more specifically, a thermoplastic resin such as PBT, PA, PEEK, or LCP.

[0094] The second resin portion 12 has an outer periphery 12a and an inner periphery 12b. Here, the outer periphery 12a and the inner periphery 12b are circular and centered on the central axis Ax, but they do not necessarily have to be circular. The inner periphery 12b is in contact with the shaft 10. The axial thickness of the second resin portion 12 is preferably 0.5 mm or more and 10 mm or less.

[0095] Second resin portion 12 is formed so as to cover at least a portion of the axial end face of bonded magnet 30. In other words, second resin portion 12 has the effect of regulating the axial position of bonded magnet 30 within magnet hole 21.

[0096] In addition, in the second embodiment, the inner periphery 20b of the rotor core 20 is spaced apart from the shaft 10. The third resin portion 13 is formed between the inner periphery 20b of the rotor core 20 and the shaft 10. The third resin portion 13 serves to hold the rotor core 20 and the shaft 10 together.

[0097] The third resin part 13 is preferably formed from the same resin as the first resin part 11. The third resin part 13 is formed from, for example, an engineering plastic with excellent heat resistance, more specifically, a thermoplastic resin such as PBT, PA, PEEK, or LCP. Here, a case will be described in which the first resin part 11, the second resin part 12, and the third resin part 13 are formed from the same material. Therefore, these resin parts 11, 12, and 13 can be molded in a single molding process.

[0098] Fig. 12 is a flowchart showing a method for manufacturing rotor 2A according to embodiment 2. In steps S101 to S103 shown in Fig. 12, similar to steps S101 to S103 (Fig. 6) according to embodiment 1, rotor core 20 is formed, and a compact, which is a precursor of bonded magnet 30, is molded into magnet hole 21 of rotor core 20.

[0099] In the next step S201, the rotor core 20 and the shaft 10 are placed in a mold 80A, which serves as a second mold for forming the resin portions 11, 12, and 13.

[0100] Fig. 13 is a cross-sectional view showing a mold 80A used to mold the resin portions 11, 12, and 13. The mold 80A is configured similarly to the mold 80 shown in Fig. 9. However, the lower mold 81 is formed with a step portion 81d for holding the rotor core 20 at a position spaced apart from the bottom surface 81c of the accommodation portion 81a.

[0101] When the rotor core 20 is accommodated in the accommodation portion 81a of the lower mold 81 and the shaft 10 is accommodated in the hole portion 81b, a cavity H1 for forming the first resin portion 11 is formed above the first end face 20c of the rotor core 20. Furthermore, a cavity H2 for forming the second resin portion 12 is formed between the second end face 20d of the rotor core 20 and the bottom surface 81c of the accommodation portion 81a. Furthermore, a cavity H3 for forming the third resin portion 13 is formed between the inner periphery 20b of the rotor core 20 and the shaft 10. These cavities H1, H2, and H3 are continuous.

[0102] In step S202, the molten resin that is the material of the resin portions 11, 12, and 13 is filled into the cavities H1, H2, and H3 from the supply path 83 of the mold 80A. The first resin portion 11 is molded in the cavity H1, the second resin portion 12 is molded in the cavity H2, and the third resin portion 13 is molded in the cavity H3.

[0103] In the following step S107, similar to step S107 (FIG. 6) in the first embodiment, the compacts in magnet holes 21 of rotor core 20 are magnetized. The magnetized compacts become bonded magnets 30. In this way, rotor 2A is completed.

[0104] In embodiment 2, the first resin part 11 covers at least a portion of one axial end face of the bonded magnet 30, and the second resin part 12 covers at least a portion of the other axial end face of the bonded magnet 30, so that the axial position of the bonded magnet 30 within the magnet hole 21 can be regulated and the bonded magnet 30 can be prevented from falling out of the magnet hole 21.

[0105] Furthermore, since the rotor core 20 and the shaft 10 are fixed by molding the third resin part 13, the process of fixing the shaft 10 to the rotor core 20 by pressing, caulking, etc. is not required, simplifying the manufacturing process.

[0106] In this example, the third resin portion 13 is formed so as to fill the gap between the rotor core 20 and the shaft 10, but a hollow portion may be provided in the third resin portion 13 (see FIG. 18 described later).

[0107] Fig. 14 is a longitudinal cross-sectional view showing a motor 1A according to embodiment 2. As shown in Fig. 14, in motor 1A, rotor core 20 and shaft 10 of rotor 2A are held by third resin portion 13. Furthermore, first resin portion 11 is formed on one axial side of rotor core 20, and second resin portion 12 is formed on the other axial side.

[0108] The rotor core 20 and shaft 10 of the rotor 2A are held together by the third resin portion 13, which is formed by injection molding, allowing for a high degree of freedom in shape. By changing the shape of the third resin portion 13, the natural frequency of the rotor 2A can be adjusted, thereby reducing vibrations of the motor 1A. Furthermore, the amount of core sheet (e.g., electromagnetic steel sheet) used to make up the rotor core 20 can be reduced, thereby reducing manufacturing costs.

[0109] Except for the points mentioned above, the rotor 2A of the second embodiment is configured similarly to the rotor 2 of the first embodiment.

[0110] As explained above, in rotor 2A of embodiment 2, first resin portion 11 is formed on first end face 20c of rotor core 20, and second resin portion 12 is formed on second end face 20d. First resin portion 11 covers at least a portion of one axial end face of bonded magnet 30, and second resin portion 12 covers at least a portion of the other axial end face of bonded magnet 30. This restricts the axial position of bonded magnet 30 within magnet hole 21 of rotor core 20, making it possible to prevent bonded magnet 30 from falling off.

[0111] Furthermore, since the rotor 2A has a third resin part 13 between the rotor core 20 and the shaft 10, processes such as pressing the shaft 10 into the rotor core 20 are not required, and vibration of the motor 1A can be reduced.

[0112] Furthermore, if the first resin part 11, the second resin part 12, and the third resin part 13 are formed from the same material, they can be molded in a single molding process, thereby simplifying the manufacturing process of the rotor 2A.

[0113] Embodiment 3. Figure 15(A) is a plan view showing a rotor 2B according to embodiment 3. Figure 15(B) is a cross-sectional view of rotor 2B taken along line 15B-15B in Figure 15(A). Rotor 2B according to embodiment 3 differs from rotor 2 according to embodiment 1 in that it has resin portions 15 within magnet holes 21 of rotor core 20.

[0114] Resin portion 15, which serves as the fourth resin portion, is provided between the inner surface of magnet hole 21 of rotor core 20 and bonded magnet 30. Resin portion 15 is preferably formed from the same resin as first resin portion 11. Resin portion 15 is formed from, for example, an engineering plastic with excellent heat resistance, more specifically, a thermoplastic resin such as PBT, PA, PEEK, or LCP.

[0115] As shown in Fig. 15(B), the resin part 15 is formed at one axial end of the magnet hole 21. However, the resin part 15 may be provided at both axial ends of the magnet hole 21 (see Fig. 16(B)), or may pass through the magnet hole 21 in the axial direction (see Fig. 17(B)).

[0116] 15(A), resin portion 15 is formed along pole surface 30b of bonded magnet 30. Therefore, resin portion 15 has a curved shape in a plane perpendicular to the axial direction, similar to pole surface 30b of bonded magnet 30. However, it is sufficient that resin portion 15 is provided in at least one location on at least one side of pole surface 30a and pole surface 30b of bonded magnet 30.

[0117] When bond magnet 30 is molded in magnet hole 21 of rotor core 20, the difference in thermal contraction between rotor core 20 and bond magnet 30 after molding may cause gap C (FIG. 15(B)) to form between the inner surface of magnet hole 21 and bond magnet 30. Due to this gap C, bond magnet 30 may move within magnet hole 21 when rotor 2B rotates, causing a collision sound and increasing noise.

[0118] In embodiment 3, a resin portion 15 is formed in the gap C between the inner surface of magnet hole 21 and bond magnet 30, thereby suppressing movement of bond magnet 30 within magnet hole 21 and reducing noise.

[0119] The resin part 15 is formed when the first resin part 11 is formed using the mold 80 described with reference to Figure 9, and part of the material forming the first resin part 11 flows into the gap C between the bond magnet 30 and the magnet hole 21.

[0120] Except for the points mentioned above, the rotor 2B of the third embodiment is configured similarly to the rotor 2 of the first embodiment.

[0121] As explained above, rotor 2B of embodiment 3 has resin portion 15 between the inner surface of magnet hole 21 of rotor core 20 and bonded magnet 30. Therefore, even if gap C occurs between bonded magnet 30 and the inner surface of magnet hole 21, resin portion 15 can restrict the movement of bonded magnet 30, thereby reducing noise.

[0122] Furthermore, since the resin portion 15 is molded in the magnet hole 21 during the molding process of the first resin portion 11, the noise reduction effect can be obtained without complicating the manufacturing process of the rotor 2B.

[0123] Embodiment 4. Figure 16(A) is a plan view showing a rotor 2C according to embodiment 4. Figure 16(B) is a cross-sectional view of rotor 2C taken along line 16B-16B in Figure 16(A). Rotor 2C according to embodiment 4 differs from rotor 2B according to embodiment 3 in that it has second resin portion 12 and third resin portion 13, and in that resin portion 15 is formed at both axial ends of magnet hole 21.

[0124] Resin portion 15, which serves as the fourth resin portion, is provided between the inner surface of magnet hole 21 of rotor core 20 and bonded magnet 30. Resin portion 15 is preferably formed from the same resin as first resin portion 11. Resin portion 15 is formed from, for example, an engineering plastic with excellent heat resistance, more specifically, a thermoplastic resin such as PBT, PA, PEEK, or LCP.

[0125] As shown in FIG. 16B, the resin portion 15 is formed at both axial ends of the magnet hole 21.

[0126] 16(A), resin portion 15 is formed along magnetic pole surface 30b of bonded magnet 30. However, it is sufficient that resin portion 15 is provided in at least one location on at least one side of magnetic pole surface 30a and magnetic pole surface 30b of bonded magnet 30.

[0127] Like rotor 2A of embodiment 2, rotor 2C has a first resin part 11 formed on the first end face 20c of rotor core 20, a second resin part 12 formed on the second end face 20d of rotor core 20, and a third resin part 13 formed between rotor core 20 and shaft 10.

[0128] By forming resin portion 15 in gap C between the inner surface of magnet hole 21 and bonded magnet 30, it is possible to suppress movement of bonded magnet 30 within magnet hole 21 and reduce noise. In particular, by forming resin portion 15 at both axial ends of magnet hole 21, it is possible to more effectively suppress movement of bonded magnet 30 within magnet hole 21 and enhance the noise reduction effect.

[0129] Resin portion 15 is formed when resin portions 11, 12, and 13 are molded using mold 80A described with reference to Fig. 13. That is, part of the material forming resin portions 11, 12, and 13 flows into gap C between bond magnet 30 and the inner surface of magnet hole 21 from both axial sides, thereby forming resin portion 15 at both axial ends of rotor core 20.

[0130] Except for the points mentioned above, the rotor 2C of the fourth embodiment is configured similarly to the rotor 2 of the first embodiment.

[0131] As explained above, rotor 2C of embodiment 4 has resin portion 15 between the inner surface of magnet hole 21 of rotor core 20 and bonded magnet 30, and resin portion 15 is provided at both axial ends of magnet hole 21. This can enhance the effect of restricting the movement of bonded magnet 30, thereby improving the effect of reducing noise.

[0132] Furthermore, since the resin portion 15 is molded in the magnet hole 21 during the molding process of the resin portions 11, 12, and 13, the noise reduction effect can be obtained without complicating the manufacturing process of the rotor 2C.

[0133] Fifth Embodiment Figure 17(A) is a plan view showing a rotor 2D according to a fifth embodiment. Figure 17(B) is a cross-sectional view of rotor 2D taken along line 17B-17B in Figure 17(A). Rotor 2D according to the fifth embodiment differs from rotor 2C according to the fourth embodiment in that resin portion 15 is formed so as to axially penetrate magnet hole 21.

[0134] Resin portion 15, which serves as the fourth resin portion, is provided between the inner surface of magnet hole 21 of rotor core 20 and bonded magnet 30. Resin portion 15 is preferably formed from the same resin as first resin portion 11. Resin portion 15 is formed from, for example, an engineering plastic with excellent heat resistance, more specifically, a thermoplastic resin such as PBT, PA, PEEK, or LCP.

[0135] As shown in FIG. 17B, the resin portion 15 is formed so as to penetrate the magnet hole 21 in the axial direction.

[0136] 17(A), resin portion 15 is formed along magnetic pole surface 30b of bonded magnet 30. However, it is sufficient that resin portion 15 is provided in at least one location on at least one side of magnetic pole surface 30a and magnetic pole surface 30b of bonded magnet 30.

[0137] Like rotor 2C of embodiment 3, rotor 2D has a first resin part 11 formed on the first end face 20c of rotor core 20, a second resin part 12 formed on the second end face 20d of rotor core 20, and a third resin part 13 formed between rotor core 20 and shaft 10.

[0138] By forming resin portion 15 in gap C between the inner surface of magnet hole 21 and bonded magnet 30, it is possible to suppress movement of bonded magnet 30 within magnet hole 21 and reduce noise. In particular, by forming resin portion 15 so as to pass through magnet hole 21 in the axial direction, it is possible to more effectively suppress movement of bonded magnet 30 within magnet hole 21 and enhance the noise reduction effect.

[0139] Resin portion 15 is formed when resin portions 11, 12, and 13 are molded using mold 80A described with reference to Fig. 13. That is, part of the material of resin portions 11, 12, and 13 flows into the entire gap C between bond magnet 30 and the inner surface of magnet hole 21, thereby forming resin portion 15 so as to penetrate magnet hole 21.

[0140] 17A and 17B, the gate mark 11e is indicated by the symbol 11e on the surface of the first resin portion 11. The gate mark 11e is formed at a position corresponding to the gate 83a of the mold 80A shown in FIG.

[0141] Gate mark 11e is desirably located radially inward of bond magnet 30. In other words, gate 83a (FIG. 13) of mold 80A is desirably located radially inward of bond magnet 30.

[0142] The injection pressure applied when molding resin portions 11, 12, and 13 acts in the axial direction from gate 83a. If gate 83a is positioned radially inward of bond magnet 30, the injection pressure can be prevented from acting on bond magnet 30. This prevents bond magnet 30 from breaking due to the injection pressure and falling out of magnet hole 21.

[0143] Furthermore, it is more desirable that the gate mark 11e be located radially inward of the inner periphery 20b of the rotor core 20. In other words, it is desirable that the gate 83a (FIG. 13) of the mold 80A be located radially inward of the inner periphery 20b of the rotor core 20.

[0144] In the mold 80A (FIG. 13), the third resin portion 13 is molded radially inward of the inner periphery 20b of the rotor core 20. Therefore, the injection pressure from the gate 83a can be received by the bottom surface 81c of the lower mold 81 of the mold 80A. The mold 80A is made of high-strength steel and therefore has sufficient durability against high injection pressure.

[0145] In this way, by preventing the injection pressure from being directly applied to bonded magnet 30 and rotor core 20, it is possible to prevent breakage of bonded magnet 30, and deformation and change in magnetic properties of rotor core 20.

[0146] Except for the points mentioned above, the rotor 2D of the fifth embodiment is configured similarly to the rotor 2 of the first embodiment.

[0147] As described above, the rotor 2D of embodiment 5 has a resin portion 15 formed so as to penetrate the magnet hole 21 of the rotor core 20, thereby enhancing the effect of restricting the movement of the bond magnet 30 and enhancing the effect of reducing noise.

[0148] Furthermore, by positioning gate mark 11e radially inward of bond magnet 30, fracture of bond magnet 30 due to injection pressure can be prevented.

[0149] Furthermore, by positioning the gate mark 11e radially inward of the inner periphery 20b of the rotor core 20, deformation of the rotor core 20 and changes in magnetic properties due to injection pressure can be suppressed.

[0150] The aspect in which gate mark 11e is located radially inward of bond magnet 30 can also be applied to rotors 2, 2A to 2C of the first to fourth embodiments.

[0151] The aspect in which the gate mark 11e is located radially inward of the inner periphery 20b of the rotor core 20 can also be applied to the rotors 2A and 2C of the second and fourth embodiments.

[0152] Sixth Embodiment Figure 18 is a cross-sectional view showing a rotor 2E according to a sixth embodiment. The rotor 2E according to the sixth embodiment differs from the rotor 2A according to the second embodiment in the shape of the third resin portion 17. The rotor 2E, like the rotor 2A, has a first resin portion 11 and a second resin portion 12 (Figure 13).

[0153] 18 , the third resin portion 17 is formed between the rotor core 20 and the shaft 10. The third resin portion 17 has an inner cylindrical portion 17a fixed to the outer periphery of the shaft 10, an outer cylindrical portion 17c fixed to the inner periphery 20b of the rotor core 20, and a plurality of ribs 17b connecting the inner cylindrical portion 17a and the outer cylindrical portion 17c. The ribs 17b extend radially from the inner cylindrical portion 17a. A cavity 17d is formed between adjacent ribs 17b in the circumferential direction.

[0154] Since the hollow portion 17d is formed in the third resin portion 17, the amount of resin used can be reduced compared to the third resin portion 13 (FIG. 11A) of the second embodiment, thereby reducing the manufacturing cost of the rotor 2E.

[0155] The number of ribs 17b is eight in this example. Of the eight ribs 17b, the above-described gate marks 11e are formed in the axial direction on four of the ribs 17b. Note that since the gate marks 11e are formed on the first resin portion 11 (see FIG. 17A), they are indicated by dashed lines in FIG.

[0156] Because gate mark 11e is located axially relative to rib 17b, the injection pressure applied from gate 83a (FIG. 13) of mold 80A can be received by lower mold 81 (FIG. 13). This prevents fracture of bonded magnet 30 due to the injection pressure, as well as deformation or change in magnetic properties of rotor core 20.

[0157] The number of ribs 17b is not limited to eight, but may be two or more. To improve the rotational balance of rotor 2E, it is desirable to form ribs 17b at equal intervals in the circumferential direction. The rotor 2E of embodiment 6 may also include resin portion 15 described in embodiments 3 to 5.

[0158] Except for the points described above, rotor 2E of embodiment 6 is configured similarly to rotor 2A of embodiment 2. Note that rotor 2E does not necessarily have to have second resin portion 12 as long as it has first resin portion 11 ( FIG. 11A ) and third resin portion 17.

[0159] As described above, in the rotor 2E of embodiment 6, the third resin portion 13 has a hollow portion, so that the amount of resin used can be reduced, and the manufacturing cost of the rotor 2E can be reduced.

[0160] 19 is a cross-sectional view showing a rotor 2F of embodiment 7. The rotor 2F of embodiment 7 differs from the rotor 2A of embodiment 2 in the shapes of the rotor core 40 and the bonded magnet 35.

[0161] The rotor core 40 is configured by combining a plurality of core segments 42 in the circumferential direction. The number of core segments 42 is, for example, 10. Each core segment 42 has a shape obtained by dividing a cylinder into equal circumferential segments. Both circumferential end faces of the core segment 42 are surfaces parallel to the axial and radial directions.

[0162] Figure 20(A) is a plan view showing a rotor 2F of embodiment 7. Figure 20(B) is a cross-sectional view taken along line 20B-20B in Figure 20(A). As shown in Figures 20(A) and 20(B), annular portions 43 that connect ten core segments 42 are formed on the outer periphery at both axial ends of the rotor core 40.

[0163] That is, ten core segments 42 are connected by annular portions 43 to form rotor core 40. Grooves 41 in which bond magnets 35 are housed are formed between adjacent core segments 42.

[0164] Bond magnet 35 is provided in groove 41 between adjacent core segments 42. The material of bond magnet 35 is the same as that of bond magnet 30 in the first to sixth embodiments.

[0165] As shown in Figure 19, bond magnet 35 is flat and has pole face 35a facing one side in the circumferential direction and pole face 35b facing the opposite side. Pole face 35a is, for example, a north pole, and pole face 35b is, for example, a south pole, but the pole faces may be reversed. Bond magnets 35 adjacent in the circumferential direction are magnetized so that pole faces of the same polarity (for example, pole face 35a) face each other. Pole face 35a is also referred to as the first pole face, and pole face 35b is also referred to as the second pole face.

[0166] 19 , bond magnet 35 extends from a position corresponding to inner periphery 40b of rotor core 40 to a position corresponding to outer periphery 40a of rotor core 40. The width direction of bond magnet 35 coincides with the radial direction of rotor core 40, and the thickness direction coincides with the circumferential direction of rotor core 40.

[0167] 20(A) and 20(B), gate mark 36 is formed on one axial end face of bonded magnet 35. Gate mark 36 is desirably formed at the center of bonded magnet 35 in the radial direction.

[0168] The rotor 2F has a first resin portion 11 formed on a first end face 40c, which is one axial end face of the rotor core 40, a second resin portion 12 formed on a second end face 40d, which is the other axial end face of the rotor core 40, and a third resin portion 13 formed between the rotor core 40 and the shaft 10. The resin portions 11, 12, and 13 are formed of, for example, an engineering plastic having excellent heat resistance, more specifically, a thermoplastic resin such as PBT, PA, PEEK, or LCP.

[0169] First resin portion 11 is formed to cover at least a portion of one axial end face of bonded magnet 35, and also to cover gate marks 36. Second resin portion 12 is formed to cover at least a portion of the other axial end face of bonded magnet 35. Third resin portion 13 is formed to connect rotor core 40 and bonded magnet 35 to shaft 10.

[0170] Furthermore, a resin portion 19 serving as a fourth resin portion is formed between the inner surface of groove portion 41 of rotor core 40 and bonded magnet 35. Resin portion 19 is preferably formed from the same material as resin portions 11, 12, and 13. Resin portion 19 is formed, for example, from an engineering plastic with excellent heat resistance, more specifically, from a thermoplastic resin such as PBT, PA, PEEK, or LCP.

[0171] The resin part 19 may be formed at one axial end of the rotor core 40 as in the resin part 15 shown in Figure 15(B), or may be formed at both axial ends of the rotor core 40 as in the resin part 15 shown in Figure 16(B), or may penetrate the rotor core 40 in the axial direction as in the resin part 15 shown in Figure 17(B).

[0172] In the manufacturing process of rotor 2F, rotor core 40 is placed in mold 70 (Figure 7) as a first mold, and grooves 41 between adjacent core segments 42 are filled with material for bonded magnet 35 to form a molded body that is a precursor of bonded magnet 35.

[0173] Then, the rotor core 40 and the shaft 10 are placed in the mold 80A (Figure 13), and the molten resin that is the material for the resin portions 11, 12, and 13 is filled into the hollow portions H1, H2, and H3 from the supply path 83 of the mold 80A.

[0174] The first resin portion 11 is molded in the cavity H1, the second resin portion 12 is molded in the cavity H2, and the third resin portion 13 is molded in the cavity H3. The material of the resin portions 11, 12, and 13 also enters the groove 41 to form the resin portion 19. The molded body in the groove 41 of the rotor core 40 is then magnetized to manufacture the rotor 2F.

[0175] In this seventh embodiment as well, it is desirable that gate mark 11e be located radially inward of bond magnet 30. This makes it possible to prevent bond magnet 30 from breaking due to the injection pressure and falling out of magnet hole 21.

[0176] Furthermore, it is more desirable that the gate mark 11e be located radially inward of the inner periphery 20b of the rotor core 40. This prevents the injection pressure from being directly applied to the rotor core 40, thereby suppressing deformation of the rotor core 40 and changes in its magnetic properties.

[0177] Except for the points described above, the rotor 2F of embodiment 7 is configured similarly to the rotor 2A of embodiment 2. A cavity like the cavity 17d of embodiment 6 may be provided in the resin portion 13. Furthermore, the rotor 2F may not have the second resin portion 12 of the first resin portion 11 and the second resin portion 12.

[0178] As described above, in the rotor 2F of embodiment 7, the rotor core 40 has a plurality of core segments 42 in the circumferential direction, and the bonded magnet 35 is formed in the groove portion 41 between adjacent core segments 42. However, since the first resin portion 11 is formed to cover the gate mark 36 of the bonded magnet 35, it is possible to prevent the resin piece of the gate mark 36 from falling off.

[0179] <Air Conditioning Apparatus> Next, an air conditioning apparatus to which the motors of the above-described embodiments can be applied will be described. Fig. 21(A) is a diagram showing the configuration of an air conditioning apparatus 500 to which the motor 1 of embodiment 1 is applied. The air conditioning apparatus 500 includes an outdoor unit 501 and an indoor unit 502. The outdoor unit 501 and the indoor unit 502 are connected by a refrigerant pipe 503.

[0180] The outdoor unit 501 includes a compressor 504, a condenser 505, and an outdoor blower 510. The outdoor blower 510 is, for example, a propeller fan. The outdoor blower 510 has an impeller 511 and a motor 1A that drives the impeller 511.

[0181] The indoor unit 502 includes an evaporator 506 and an indoor blower 520. The indoor blower 520 is, for example, a cross-flow fan. The indoor blower 520 has an impeller 521 and a motor 1B that drives the impeller 521.

[0182] 21(B) is a vertical cross-sectional view of the outdoor unit 501. The motor 1A is supported by a frame 509 disposed within a housing 508 of the outdoor unit 501. An impeller 511 is attached to the shaft 10 of the motor 1A via a hub 512.

[0183] The outdoor blower 510 blows air to the outside by rotating an impeller 511 driven by a motor 1A. During cooling operation of the air conditioner 500, the heat released when the refrigerant compressed by the compressor 504 condenses in the condenser 505 is released to the outside by the air blown by the outdoor blower 510.

[0184] The indoor fan 520 (FIG. 21A) blows air into the room by rotating an impeller 521 with a motor 1B. During cooling operation of the air conditioner 500, the indoor fan 520 blows air cooled when the refrigerant evaporates in the evaporator 506 into the room.

[0185] Motors 1A and 1B are configured as motor 1 according to embodiment 1. Motor 1 according to embodiment 1 has high reliability due to prevention of resin pieces from gate mark 31 from falling off. This improves the reliability of outdoor blower 510 and indoor blower 520, thereby improving the reliability of air conditioning apparatus 500.

[0186] Motors 1A and 1B are not limited to motor 1 of embodiment 1, but may be motors having rotors of embodiments 2 to 7. Also, although the motors of each embodiment are used in both outdoor fan 510 and indoor fan 520 here, they may be used in only one of them.

[0187] Furthermore, the motors of the first to seventh embodiments are not limited to being used in blowers, but may also be used as motors for compressors or other devices.

[0188] Although the preferred embodiments have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various improvements and modifications can be made.

[0189] DESCRIPTION OF SYMBOLS 1, 1A Motor, 2, 2A, 2B, 2C, 2D, 2E, 2F Rotor, 5 Stator, 6 Molded stator, 10 Shaft, 11 First resin portion, 11a Outer periphery, 11b Inner periphery, 11e Gate mark, 12 Second resin portion, 13 Third resin portion, 15, 19 Resin portion (fourth resin portion), 20 Rotor core, 20c First end face, 20d Second end face, 21 Magnet hole, 30 Bonded magnet, 30a Magnetic pole surface (first magnetic pole surface), 30b Magnetic pole surface (second magnetic pole surface), 31 Gate mark, 40 Rotor core, 40c First end face, 40d Second end face, 41 Groove portion, 42 Core segment, 43 Annular portion (connecting portion), 50 Stator core, 55 Coil, 70 Mold, 71 Lower mold, 72 Upper mold, 73a Gate, 80, 80A Mold, 81 Lower mold, 82 Upper mold, 83a Gate, 500 Air conditioning device, 501 Outdoor unit, 502 Indoor unit, 510 Outdoor blower (blower), 511 Impeller, 520 Indoor blower (blower), 521 Impeller.

Claims

1. A rotor comprising: a shaft; an annular rotor core fixed to the shaft, having magnet holes and surrounding the shaft from the radial outside; a bonded magnet provided in the magnet hole; and a first resin portion provided on an end face of the rotor core in the axial direction of the shaft, wherein a gate mark is formed on the axial end face of the bonded magnet, and the first resin portion covers the gate mark of the bonded magnet.

2. The rotor according to claim 1, wherein a minimum distance R1 from a central axis of the shaft to an outer periphery of the first resin portion and a minimum distance R2 from the central axis to the gate mark satisfy R1 > R2.

3. The rotor according to claim 1 or 2, wherein a minimum distance R1 from the central axis of the shaft to the outer periphery of the first resin portion and a minimum distance R3 from the central axis to the outer periphery of the rotor core satisfy R1 < R3.

4. A rotor according to any one of claims 1 to 3, wherein the first resin portion is formed so as to be in contact with the shaft.

5. A rotor as claimed in any one of claims 1 to 4, further comprising a second resin portion formed on the end face of the rotor core opposite to the side on which the first resin portion is formed, the second resin portion covering at least a portion of the bonded magnet.

6. The rotor according to claim 5, further comprising a third resin portion between the rotor core and the shaft, the first resin portion, the second resin portion and the third resin portion being integrally formed.

7. A rotor according to any one of claims 1 to 6, further comprising a fourth resin portion between the inner surface of the magnet hole of the rotor core and the bonded magnet.

8. The rotor according to claim 7, wherein the fourth resin portion is formed at an end portion of the rotor core in the axial direction, the end portion being on the same side as the gate mark.

9. The rotor according to claim 7 or 8, wherein the fourth resin portion is formed at both ends of the rotor core in the axial direction.

10. A rotor according to any one of claims 7 to 9, wherein the fourth resin portion penetrates the rotor core in the axial direction.

11. A rotor as described in any one of claims 7 to 10, wherein the first resin portion, a second resin portion formed on the end face of the rotor core opposite to the side on which the first resin portion is formed, a third resin portion formed between the rotor core and the shaft, and the fourth resin portion are integrally formed.

12. A rotor as claimed in any one of claims 1 to 11, wherein a gate mark is formed in the first resin portion, and the gate mark in the first resin portion is formed radially inward from the shaft center relative to the bonded magnet.

13. A rotor as claimed in any one of claims 1 to 12, wherein a gate mark is formed in the first resin part, and the gate mark in the first resin part is formed radially inward from the shaft center rather than the inner circumference of the rotor core.

14. A rotor as claimed in any one of claims 1 to 13, wherein the rotor core has two or more core segments arranged in a circumferential direction around the shaft, and the magnet holes are grooves formed between two adjacent core segments.

15. A motor comprising: a rotor according to any one of claims 1 to 14; and a stator provided so as to surround the rotor.

16. The motor according to claim 15, wherein the gate marks of the bonded magnet are located outside the stator core of the stator in the axial direction.

17. A blower comprising: a motor according to claim 15 or 16; and an impeller rotated by said motor.

18. An air-conditioning apparatus comprising an outdoor unit and an indoor unit, at least one of the outdoor unit and the indoor unit having a blower according to claim 17.

19. A method for manufacturing a rotor, comprising the steps of: forming an annular rotor core having magnet holes; injecting a material containing magnetic powder and resin into the magnet holes to form a molded body; fixing the rotor core to a shaft provided radially inside the rotor core; forming a first resin portion on the axial end face of the shaft of the rotor core so as to cover a gate mark formed on the axial end face of the molded body; and magnetizing the molded body in the magnet holes to form a bonded magnet.

20. The method for manufacturing a rotor according to claim 19, further comprising the step of forming a second resin portion on the end face of the rotor core opposite to the end face on which the first resin portion is formed.

21. The method of manufacturing a rotor according to claim 20, further comprising the step of forming a third resin portion between the rotor core and the shaft, integrally with the first resin portion and the second resin portion.

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