Bonded magnet manufacturing method, rotor, motor, blower, and refrigeration device

Abstract

In bonded magnets formed by injection molding, there is room for improvement in adjusting the orientation rate of magnetic powder. [Solution] A method for manufacturing a bonded magnet includes an injection step of injecting a bonded magnet material containing magnetic powder through an injection port 62 into a molding die 60 having a mold body 61 with an injection port 62 and a cylindrical cavity 63. The cavity 63 has a first region 64 and a second region 65 in a cross section perpendicular to the cylindrical axis direction CD of the cavity 63. The second region 65 is a region different from the first region 64 in the circumferential direction of the cavity 63. In the radial direction of the cavity 63, the length of the first region 64 is shorter than the length of the second region 65. The injection port 62 is provided in the first region 64.

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a bonded magnet, a rotor, a motor, a blower, and a refrigeration device. [Background technology]

[0002] An anisotropic bonded magnet is disclosed in Patent Document 1. In the bonded magnet disclosed in Patent Document 1, the orientation and magnetization direction of the magnetic powder are controlled by an orienting magnet provided on the inner periphery of the annular bonded magnet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-142635 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not take into consideration the orientation of magnetic powder during injection molding. There is room for improvement in adjusting the orientation rate of magnetic powder in bonded magnets formed by injection molding. [Means for solving the problem]

[0005] A first aspect of the method for manufacturing a bonded magnet that solves the above problem includes an injection step of injecting a bonded magnet material containing magnetic powder into a molding die having a mold body with an injection port and a cylindrical cavity through the injection port, wherein the cavity has a first region and a second region in a cross section perpendicular to the cylindrical axis of the cavity, the second region being a region different from the first region in the circumferential direction of the cavity, the length of the first region being shorter than the length of the second region in the radial direction of the cavity, and the injection port being provided in the first region.

[0006] According to the above configuration, by injecting the bond magnet material through the injection port provided in the first region, it is possible to improve the orientation rate of the magnetic powder along the direction spreading from the first region toward the second region.

[0007] A second aspect of the method for manufacturing a bonded magnet is the method for manufacturing a bonded magnet of the first aspect, wherein the molding die is arranged on the inner or outer surface side of the cavity in the radial direction and further includes a magnetic field generating unit that generates a magnetic field within the cavity, the magnetic field generating unit having magnetic poles arranged side by side in the circumferential direction, and the first region faces the center of the magnetic poles in the radial direction.

[0008] According to the above configuration, the injection port is provided in the first region facing the center of the magnetic pole of the magnetic field generating unit in the radial direction, so that the orientation rate of the magnetic powder along the magnetic flux of the magnetic field generating unit can be improved.

[0009] A third aspect of the invention relates to a method for producing a bonded magnet, in which in the injecting step, the bonded magnet material is injected into the injection port from the cylindrical axis direction.

[0010] According to the above configuration, the bonded magnet can be suitably molded by injecting the bonded magnet material from the cylindrical axis direction.

[0011] A fourth aspect of the invention relates to a method for producing a bonded magnet, in which the injection port is provided on an end face of the cavity in the cylindrical axis direction.

[0012] According to the above configuration, in the injection step, the bonded magnet material is injected from the end face of the cavity in the cylindrical axis direction, thereby making it possible to suitably mold the bonded magnet.

[0013] A fifth aspect of the method for manufacturing a bonded magnet is the method for manufacturing a bonded magnet of any one of the first to fourth aspects, further comprising a magnetizing step of magnetizing the bonded magnet, the magnetizing step being carried out after the injection step.

[0014] According to the above configuration, the bonded magnet can be suitably magnetized in the magnetizing step.

[0015] A sixth aspect of the present invention provides a motor rotor that solves the above-described problems, the motor rotor comprising a cylindrical bonded magnet, the bonded magnet including magnetic powder that is longer in a second direction perpendicular to the easy axis of magnetization than in a first direction along the easy axis of magnetization, the bonded magnet being a polar anisotropic magnet having two or more magnetic poles that are adjacent in the circumferential direction of the bonded magnet, the bonded magnet having a first portion that includes the magnetic poles and a second portion that is located midway between the adjacent magnetic poles in the circumferential direction, the length of the first portion being shorter than the length of the second portion in the radial direction of the bonded magnet, and the first portion having gate marks formed thereon where bonded magnet material was injected.

[0016] According to the above configuration, the bonded magnet is injection molded near the first portion including the magnetic poles, which makes it possible to improve the orientation rate of the magnetic powder during injection molding.

[0017] A rotor according to a seventh aspect is the rotor according to the sixth aspect, wherein an outer peripheral surface of the second portion is positioned outside an outer peripheral surface of the first portion in the radial direction.

[0018] According to the above configuration, the magnetic powder is oriented in accordance with the shape of the outer peripheral surface of the second portion, thereby improving the orientation rate of the magnetic powder.

[0019] A rotor according to an eighth aspect is the rotor according to the seventh aspect, wherein an inner circumferential surface of the first portion is located more inward than an inner circumferential surface of the second portion in the radial direction.

[0020] According to the above configuration, the magnetic powder is oriented in accordance with the shape of the inner circumferential surface of the second portion, thereby improving the orientation rate of the magnetic powder.

[0021] A rotor according to a ninth aspect is the rotor according to the sixth aspect, wherein the ratio of the length of the first portion to the length of the second portion in the radial direction is equal to or greater than 0.5 and less than 1.0.

[0022] According to the above configuration, the shape allows the magnetic powder to be easily oriented in a suitable manner, thereby improving the orientation rate of the magnetic powder.

[0023] A rotor according to a tenth aspect is the rotor according to the sixth aspect, wherein a first orientation ratio of the magnetic powder in the radial direction in the magnetic poles of the first portion is greater than a second orientation ratio of the magnetic powder in the circumferential direction in the second portion.

[0024] According to the above configuration, the orientation rate of the magnetic powder in the gate trace can be improved.

[0025] A rotor of an eleventh aspect is a rotor of any one of the sixth to tenth aspects, wherein in the first portion, the number of magnetic particles in a unit volume where the easy magnetic axes of the magnetic particles face the radial direction is greater than the number of magnetic particles in a unit volume where the easy magnetic axes of the magnetic particles face the circumferential direction, and in the second portion, the number of magnetic particles in a unit volume where the easy magnetic axes of the magnetic particles face the circumferential direction is greater than the number of magnetic particles in a unit volume where the easy magnetic axes of the magnetic particles face the radial direction.

[0026] According to the above configuration, the easy magnetization axis of the magnetic powder is oriented in a preferred direction, thereby improving the orientation rate of the magnetic powder.

[0027] A rotor according to a twelfth aspect is the rotor according to any one of the sixth to eleventh aspects, wherein the gate marks are formed on an end face of the bonded magnet in the axial direction of the bonded magnet.

[0028] According to the above configuration, the bonded magnet can be formed by injection molding from the axial direction.

[0029] A rotor according to a thirteenth aspect is the rotor according to any one of the sixth to twelfth aspects, wherein the bonded magnets are covered with resin.

[0030] According to the above configuration, the strength of the bonded magnet can be improved by the resin.

[0031] A motor according to a fourteenth aspect includes the rotor according to any one of the sixth to thirteenth aspects and a stator.

[0032] According to the above configuration, the motor can improve its performance by using a rotor including a bonded magnet with an improved orientation rate of magnetic powder.

[0033] A fifteenth aspect of the present invention provides a blower including the motor of the fourteenth aspect and a fan unit driven by the motor.

[0034] According to the above configuration, the blower can preferably blow air by driving the fan portion with a motor having improved performance.

[0035] A refrigeration device according to a sixteenth aspect includes the motor according to the fourteenth aspect.

[0036] According to the above configuration, the refrigeration apparatus can improve the energy utilization efficiency of the refrigeration apparatus by using a motor with improved performance. [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a schematic diagram of an indoor unit for a refrigeration device according to an embodiment. [Figure 2] 2 is a cross-sectional view showing a motor and a fan of an indoor unit for the refrigeration apparatus of FIG. 1. [Figure 3] FIG. 3 is a plan view of a mold for forming a bonded magnet to be provided in the rotor of the motor of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of the mold for the bonded magnet taken along line D4-D4 in FIG. [Figure 5] FIG. 5 is a cross-sectional view of the mold for the bonded magnet taken along line D5-D5 in FIG. [Figure 6] FIG. 3 is a perspective view of a bonded magnet provided in the rotor of the motor of FIG. 2. [Figure 7] FIG. 7 is a plan view of the bonded magnet of FIG. 6. [Figure 8] FIG. 8 is an enlarged plan view of a portion of the bonded magnet of FIG. 7. [Figure 9] FIG. 10 is an enlarged plan view of a portion of a modified bonded magnet. [Figure 10] FIG. 10 is a cross-sectional view of a modified bonded magnet. DETAILED DESCRIPTION OF THE INVENTION

[0038] <Embodiment> A method for manufacturing bonded magnet 50 of the embodiment, rotor 40 of motor 20, motor 20, blower 10, and a refrigeration device will be described with reference to FIGS. 1 to 8. FIG.

[0039] The refrigeration device includes a motor 20. Examples of refrigeration devices include air conditioners, water heaters, chiller units, and cooling devices that cool the air inside a storage unit. The air conditioner is either a dedicated refrigeration unit, a dedicated heating unit, or a cooling / heating unit that can switch between cooling and heating. The air inside the storage unit is the air inside a refrigerator, a freezer, a showcase, a container, etc. In this embodiment, the refrigeration device will be described as an air conditioner.

[0040] 1 shows an indoor unit 1 of an air conditioner. In this embodiment, a motor 20 is provided in the indoor unit 1. The indoor unit 1 is, for example, a wall-mounted type that is attached to a wall inside a room. The indoor unit 1 is connected to an outdoor unit of the air conditioner by a refrigerant pipe.

[0041] The indoor unit 1 has a heat exchanger that exchanges heat with the air drawn in through the air inlet, a blower 10, and a casing 2 that supports the heat exchanger and the blower 10. The heat exchanger and the blower 10 are disposed in the internal space of the casing 2.

[0042] The blower 10 includes a motor 20 and a fan unit 11 driven by the motor 20. The fan unit 11 is provided downstream of the heat exchanger in the air flow path from the air inlet to the air outlet of the indoor unit 1. The fan unit 11 is a propeller fan, a centrifugal fan, or a cross-flow fan. Examples of centrifugal fans include a turbo fan and a sirocco fan. In this embodiment, the fan unit 11 is a cross-flow fan.

[0043] <Motor> 2, the motor 20 is, for example, an outer rotor type motor. The motor 20 includes a rotor 40 and a stator 30.

[0044] The stator 30 has a stator body 30A, a stator core 31, and coils 32. These members constituting the stator 30 are integrally formed by resin molding. The stator body 30A is disposed radially inside the rotor 40.

[0045] The stator core 31 is formed by laminating conductive steel plates. The steel plates are soft magnetic materials. The stator core 31 has a plurality of teeth. The coil 32 is formed by winding a wire around the teeth of the stator core 31. The wire is made of copper wire or aluminum wire. The wire is covered with an insulating material such as enamel resin.

[0046] An insulator is provided between the stator core 31 and the coil 32. The insulator is made of an insulating resin material. The insulator insulates between the stator core 31 and the coil 32 so that the current flowing through the coil 32 is not transmitted to the stator core 31.

[0047] Stator 30 further has a cylindrical stator outer periphery 33 and a connecting portion 34 that connects stator main body 30A and stator outer periphery 33. Stator outer periphery 33 is provided radially outside stator main body 30A. Connecting portion 34 connects stator main body 30A and stator outer periphery 33. A housing chamber 35 is formed between stator main body 30A and stator outer periphery 33. Housing chamber 35 is configured in an annular shape when viewed from the axial direction AD of bonded magnet 50.

[0048] The motor 20 further includes a rotating shaft 21. The stator 30 has a through hole 36 in which the rotating shaft 21 is disposed. At least one bearing 22 is disposed in the through hole 36. The bearing 22 supports the rotating shaft 21 so that the rotating shaft 21 rotates relative to the stator 30. A rotor 40 is attached to one end of the rotating shaft 21. In this embodiment, the rotating shaft 21 is supported by the two bearings 22 so as to be rotatable relative to the stator 30.

[0049] Rotor 40 includes cylindrical bonded magnet 50. At least a portion of bonded magnet 50 is disposed in housing chamber 35. Bonded magnet 50 is disposed radially outside stator body 30A. Bonded magnet 50 is disposed radially inside stator outer periphery 33.

[0050] Rotor 40 further includes cover member 41. Bond magnet 50 is formed separately from cover member 41 and is attached to cover member 41 so as to rotate integrally with cover member 41. Cover member 41 is provided at one end of bond magnet 50 in the axial direction AD of bond magnet 50. Bond magnet 50 is attached to cover member 41 by, for example, an attachment claw. Bond magnet 50 may also be attached to cover member 41 by an adhesive or the like.

[0051] Cover member 41 is made of a resin material. The resin material that forms cover member 41 is preferably the same as the resin material of the binder used in bonded magnet 50. The resin material that forms cover member 41 may be different from the resin material of the binder used in bonded magnet 50.

[0052] Cover member 41 has axial cover portion 41A and radial cover portion 41B extending from axial cover portion 41A in axial direction AD. Axial cover portion 41A is connected to one end of bonded magnet 50 in axial direction AD. Radial cover portion 41B at least partially covers bonded magnet 50 and the radial outside of stator 30.

[0053] <Bonded magnet> 6 to 8, bonded magnet 50 will be described. Bonded magnet 50 is a polar anisotropic magnet having two or more magnetic poles adjacent in the circumferential direction of bonded magnet 50. Bonded magnet 50 is formed from a bonded magnet material. The bonded magnet material includes magnetic powder and a binder.

[0054] The magnetic powder has an easy axis of magnetization. The length of the magnetic powder in a second direction perpendicular to the easy axis of magnetization is longer than the length in a first direction along the easy axis of magnetization. The magnetic powder has a flat shape. The magnetic powder is in the form of a fine powder or particles. The magnetic powder is a ferrite magnetic powder or a rare earth magnetic powder. The rare earth magnetic powder includes an NdFeB magnetic powder or an SmCo magnetic powder.

[0055] As the binder, nylon resin, PPS (Poly Phenylene Sulfide) resin, etc. Examples of nylon resin include nylon 12, nylon 6, nylon 6,6, nylon 11, nylon 6,12, nylon 6,10, nylon 6,66, nylon MXD6, etc. Various nylon resins may be used alone or in combination.

[0056] Bonded magnet 50 has first portion 51 including a magnetic pole and second portion 52 located midway between circumferentially adjacent magnetic poles. Second portion 52 is a portion that differs from first portion 51 in the circumferential direction of bonded magnet 50. Second portion 52 may be partially located midway between circumferentially adjacent magnetic poles.

[0057] Gate mark 53, where bond magnet material was injected, is formed in first portion 51. Gate mark 53 is an injection mark of bond magnet material formed corresponding to the position of injection port 62 provided in molding die 60, which will be described later. Gate mark 53 is formed on end face 50A of bond magnet 50 in axial direction AD of bond magnet 50.

[0058] The d-axis shown in FIG. 8 is an axis that passes through the center of the magnetic pole of bonded magnet 50. The q-axis shown in FIG. 8 is an axis that is electrically and magnetically perpendicular to the d-axis. The d-axis is located at the center of first portion 51 in the circumferential direction. The q-axis is located at the center of second portion 52 in the circumferential direction. At least a portion of gate mark 53 passes through the d-axis, for example.

[0059] In the radial direction of bonded magnet 50, the length of first portion 51 is shorter than the length of second portion 52. In the radial direction of bonded magnet 50, the length of the maximum portion of first portion 51 is shorter than the length of the minimum portion of second portion 52. In the radial direction of bonded magnet 50, the ratio of the length of the maximum portion of first portion 51 to the length of the minimum portion of second portion 52 is greater than or equal to 0.5 and less than 1.0.

[0060] First portion 51 has an outer peripheral surface 51A and an inner peripheral surface 51B. Second portion 52 has an outer peripheral surface 52A and an inner peripheral surface 52B. Outer peripheral surface 52A of second portion 52 is located outward from outer peripheral surface 51A of first portion 51 in the radial direction of bonded magnet 50. Outer peripheral surface 52A at the smallest portion of second portion 52 is located outward from outer peripheral surface 51A of first portion 51 at the largest portion in the radial direction of bonded magnet 50. Inner peripheral surface 51B of first portion 51 is continuous with inner peripheral surface 52B of second portion 52.

[0061] In this embodiment, orientation means that the easy axis of magnetization of the magnetic particles contained in the bonded magnet material is aligned along a specific direction. The orientation rate is defined as the average value of the orientation component of each magnetic particle relative to the specific direction by the following equation (1).

number

[0062] In formula (1), X is the orientation rate. In formula (1), N is the total number of magnetic particles contained in an arbitrary region. In formula (1), θ is the angle between a predetermined direction and the easy axis of magnetization of each magnetic particle. The arbitrary region is set, for example, by the observation range of a scanning electron microscope (SEM).

[0063] The first orientation ratio of the magnetic powder in the radial direction of bonded magnet 50 in the magnetic pole of first portion 51 is greater than the second orientation ratio of the magnetic powder in the circumferential direction in second portion 52. The magnetic flux of bonded magnet 50 in the magnetic pole is substantially aligned with the radial direction of bonded magnet 50. Therefore, the closer to the magnetic pole of bonded magnet 50, the more the magnetization easy axis of the magnetic powder is aligned with the magnetic flux of magnetic field generating unit 66. The first orientation ratio is calculated, for example, as the average value of the orientation components of each magnetic powder in the radial direction in the magnetic pole of first portion 51. The second orientation ratio is calculated as the average value of the orientation components of each magnetic powder in the circumferential direction in second portion 52.

[0064] In first portion 51, the number of magnetic particles in a unit volume where the easy axis of magnetization of the magnetic particles faces the radial direction of bonded magnet 50 is greater than the number of magnetic particles in a unit volume where the easy axis of magnetization of the magnetic particles faces the circumferential direction. In second portion 52, the number of magnetic particles in a unit volume where the easy axis of magnetization of the magnetic particles faces the circumferential direction is greater than the number of magnetic particles in a unit volume where the easy axis of magnetization of the magnetic particles faces the radial direction of bonded magnet 50.

[0065] <Manufacturing method of bonded magnets> A method for manufacturing bonded magnet 50 will be described with reference to FIGS.

[0066] Bond magnet 50 is molded using molding die 60. Molding die 60 includes a mold body 61. Mold body 61 has an injection port 62 and a cylindrical cavity 63. Inlet 62 is circular. Inlet 62 is provided on end face 63A of cavity 63 in the cylindrical axis direction CD. End face 63A of cavity 63 in the cylindrical axis direction CD is annular.

[0067] The cavity 63 has a first region 64 and a second region 65 in a cross section perpendicular to the cylinder axis direction CD of the cavity 63. The second region 65 is a region different from the first region 64 in the circumferential direction of the cavity 63. In the radial direction of the cavity 63, the length of the first region 64 is shorter than the length of the second region 65. The first region 64 is adjacent to the second region 65 in the circumferential direction.

[0068] At least a portion of the injection port 62 is provided in the first region 64. In this embodiment, the entire injection port 62 is provided in the first region 64. In the circumferential direction of the cavity 63, the length of the first region 64 is equal to or greater than the length of the injection port 62.

[0069] The molding die 60 further includes a magnetic field generating unit 66 that is disposed on the inner surface 63B side or the outer surface 63C side of the cavity 63 in the radial direction of the cavity 63 and that generates a magnetic field within the cavity 63. In this embodiment, the magnetic field generating unit 66 is disposed on the inner surface 63B side of the cavity 63. The magnetic field generating unit 66 has magnetic poles that are arranged side by side in the circumferential direction. The magnetic field generating unit 66 has south poles and north poles that are arranged alternately in the circumferential direction on the outer periphery of the magnetic field generating unit 66.

[0070] The number of magnetic poles of the bond magnet 50 corresponds to the number of magnetic poles of the magnetic field generating unit 66. In this embodiment, the number of magnetic poles of the magnetic field generating unit 66 is 10. The number of magnetic poles of the magnetic field generating unit 66 is not limited to 10. The magnetic field generating unit 66 may have magnetic poles equal to a natural even number greater than or equal to 2. The first region 64 faces the center of the magnetic poles in the radial direction of the cavity 63.

[0071] In the cavity 63, first regions 64 and second regions 65 are alternately arranged. In the radial direction of the cavity 63, the length of the first regions 64 is shorter than the length of the second regions 65. In the radial direction of the cavity 63, the length of the maximum portion of the first regions 64 is shorter than the length of the minimum portion of the second regions 65. In the radial direction of the cavity 63, the ratio of the length of the minimum portion of the first regions 64 to the length of the maximum portion of the second regions 65 is equal to or greater than 0.5 and less than 1.0.

[0072] The first region 64 has an outer surface 64A and an inner surface 64B. In the radial direction of the cavity 63, the distance from each end of the outer surface 64A of the first region 64 to the magnetic pole is equal to or greater than the distance from the middle portion of the outer surface 64A of the first region 64 to the magnetic pole. In the radial direction of the cavity 63, the outer surface 64A of the first region 64 curves from the middle portion of the outer surface 64A of the first region 64 toward each end of the outer surface 64A of the first region 64.

[0073] The second region 65 has an outer surface 65A and an inner surface 65B. The outer surface 65A of the second region 65 is curved with a higher curvature than the inner surface 65B of the second region 65. In the radial direction of the cavity 63, each end of the outer surface 65A of the second region 65 is located more inward than the remaining portions of the outer surface 65A of the second region 65. In the radial direction of the cavity 63, the distance from each end of the outer surface 65A of the second region 65 to the injection port 62 is closer than the distance from the remaining portions of the outer surface 65A of the second region 65 to the injection port 62. The outer surface 65A of the second region 65 is curved such that it moves away from the end of the outer surface 65A of the second region 65 in the circumferential direction of the cavity 63 as it moves radially outward from the end of the outer surface 65A of the second region 65.

[0074] The outer surface 65A of the second region 65 is located outward in the radial direction of the cavity 63 than the outer surface 64A of the first region 64. The outer surface 65A of the second region 65 at its smallest portion is located outward in the radial direction of the cavity 63 than the outer surface 64A of the first region 64 at its largest portion. In this embodiment, the cavity 63 has a petal shape. The cavity 63 has a shape that follows the flow of magnetic powder in the bonded magnet material. The cavity 63 has a shape that smoothly connects the first region 64 to the second region 65. The cavity 63 has a shape such that its radial width monotonically increases from the first region 64 to the second region 65. The cavity 63 has a shape such that its radial width monotonically decreases from the second region 65 to the first region 64.

[0075] The molding die 60 includes a movable part 68 that is configured to be movable relative to the mold body 61. The movable part 68 has an injection port 68A and a runner 68B. A bonded magnet material containing magnetic powder is injected into the injection port 68A. The runners 68B are arranged on the movable part 68 so that they spread radially. The bonded magnet material injected from the injection port 68A is injected into the cavity 63 via the runners 68B and the injection port 62.

[0076] The manufacturing method of bonded magnet 50 includes an injection step of injecting bonded magnet material containing magnetic powder into molding die 60 through injection port 62. The injection step is a step for injection molding bonded magnet 50. In the injection step, the bonded magnet material is injected into injection port 62 from the cylindrical axis direction CD. In the injection step, once the bonded magnet material is injected from injection port 68A, it passes through runner 68B and is injected into cavity 63 from injection port 62.

[0077] During the injection process, the bond magnet material flows downward from the injection port 62 and in a direction spreading circumferentially, filling the cavity 63. The bond magnet material injected from the injection port 62 flows so as to spread from the first region 64 toward the second region 65, and the magnetization easy axis of the magnetic powder faces in the direction spreading from the first region 64 toward the second region 65. The arrows in FIG. 5 indicate the flow of the bond magnet material. A weld is formed where the bond magnet materials injected from each injection port 62 come into contact with each other. The position where the weld is formed substantially corresponds to the q-axis of the bond magnet 50.

[0078] The manufacturing method of bonded magnet 50 further includes a separation step in which movable part 68 is moved in a direction away from mold body 61. The separation step is performed after the injection step is completed and the bonded magnet material has hardened. By the separation step, the bonded magnet material in cavity 63 is separated from the bonded magnet material in runner 68B.

[0079] The manufacturing method of bonded magnet 50 further comprises a removal step in which bonded magnet 50 is removed from cavity 63. The manufacturing method of bonded magnet 50 further comprises a magnetizing step in which bonded magnet 50 is magnetized. The magnetizing step is performed after the injection step. Preferably, the magnetizing step is performed after the removal step.

[0080] <Operation of the embodiment> The operation of this embodiment will be described. In this embodiment, since the injection port 62 is located in the first region 64, during the injection process the bond magnet material flows so as to spread from the first region 64 towards the second region 65. Therefore, the easy axis of magnetization of the magnetic powder faces in the direction spreading from the first region 64 towards the second region 65.

[0081] <Effects of the embodiment> The effects of the embodiment will be described. (1) The manufacturing method of bonded magnet 50 includes an injection step of injecting a bonded magnet material containing magnetic powder through injection port 62 into a molding die 60 having a mold body 61 with injection port 62 and a cylindrical cavity 63. Cavity 63 has a first region 64 and a second region 65 in a cross section perpendicular to the cylindrical axis direction CD of cavity 63. Second region 65 is a region different from first region 64 in the circumferential direction of cavity 63. In the radial direction of cavity 63, the length of first region 64 is shorter than the length of second region 65. Injection port 62 is provided in first region 64.

[0082] According to the above configuration, by injecting the bond magnet material from the injection port 62 provided in the first region 64, the orientation rate of the magnetic powder along the direction spreading from the first region 64 toward the second region 65 can be improved.

[0083] (2) The molding die 60 further includes a magnetic field generating unit 66 that is disposed on the inner surface 63B or outer surface 63C of the cavity 63 in the radial direction and generates a magnetic field within the cavity 63. The magnetic field generating unit 66 has magnetic poles that are arranged side by side in the circumferential direction. The first region 64 faces the center of the magnetic poles in the radial direction.

[0084] According to the above configuration, the injection port 62 is provided in the first region 64 that faces the center of the magnetic pole of the magnetic field generating unit 66 in the radial direction, thereby improving the orientation rate of the magnetic powder along the magnetic flux of the magnetic field generating unit 66.

[0085] (3) In the injection step, the bond magnet material is injected into the injection port 62 from the cylinder axis direction CD.

[0086] According to the above configuration, bonded magnet 50 can be suitably molded by injecting the bonded magnet material from the cylinder axis direction CD.

[0087] (4) The injection port 62 is provided on the end surface 63A of the cavity 63 in the cylindrical axis direction CD.

[0088] According to the above configuration, in the injection step, bond magnet material is injected from end surface 63A of cavity 63 in the cylinder axis direction CD, thereby making it possible to suitably mold bond magnet 50.

[0089] (5) The method for manufacturing bonded magnet 50 further includes a magnetizing step of magnetizing bonded magnet 50. The magnetizing step is carried out after the injection step.

[0090] According to the above configuration, bond magnet 50 can be suitably magnetized in the magnetizing step.

[0091] (6) The rotor 40 of the motor 20 includes a cylindrical bonded magnet 50. The bonded magnet 50 includes magnetic powder whose length in a second direction perpendicular to the easy axis of magnetization is longer than its length in a first direction along the easy axis of magnetization. The bonded magnet 50 is a polar anisotropic magnet having two or more magnetic poles adjacent in the circumferential direction of the bonded magnet 50. The bonded magnet 50 has a first portion 51 including the magnetic poles and a second portion 52 located midway between the adjacent magnetic poles in the circumferential direction. In the radial direction of the bonded magnet 50, the length of the first portion 51 is shorter than the length of the second portion 52. A gate mark 53 where the bonded magnet material was injected is formed in the first portion 51.

[0092] According to the above configuration, bonded magnet 50 is injection molded near first portion 51, which includes the magnetic poles. Therefore, the orientation rate of the magnetic powder during injection molding can be improved.

[0093] (7) The outer circumferential surface 52A of the second portion 52 is located radially outward of the outer circumferential surface 51A of the first portion 51.

[0094] According to the above configuration, the magnetic powder is oriented in accordance with the shape of the outer circumferential surface 52A of the second portion 52. Therefore, the orientation rate of the magnetic powder can be improved.

[0095] (8) In the radial direction, the ratio of the length of the first portion 51 to the length of the second portion 52 is equal to or greater than 0.5 and less than 1.0.

[0096] According to the above configuration, the shape allows the magnetic powder to be easily oriented in a suitable manner, thereby improving the orientation rate of the magnetic powder.

[0097] (9) The first orientation ratio of the magnetic powder in the radial direction of the magnetic pole of the first portion 51 is greater than the second orientation ratio of the magnetic powder in the circumferential direction of the second portion 52.

[0098] According to the above configuration, the orientation rate of the magnetic powder in the gate marks 53 can be improved.

[0099] (10) In the first portion 51, the number of magnetic particles in a unit volume whose easy magnetic axes are oriented in the radial direction is greater than the number of magnetic particles in a unit volume whose easy magnetic axes are oriented in the circumferential direction. In the second portion 52, the number of magnetic particles in a unit volume whose easy magnetic axes are oriented in the circumferential direction is greater than the number of magnetic particles in a unit volume whose easy magnetic axes are oriented in the radial direction.

[0100] According to the above configuration, the easy magnetization axis of the magnetic powder is oriented in a preferred direction, thereby improving the orientation rate of the magnetic powder.

[0101] (11) Gate mark 53 is formed on end surface 50A of bonded magnet 50 in axial direction AD of bonded magnet 50.

[0102] According to the above configuration, bonded magnet 50 can be formed by injection molding from the axial direction AD.

[0103] (12) The motor 20 includes a rotor 40 and a stator 30.

[0104] According to the above configuration, the motor 20 can improve its performance by using the rotor 40 including the bonded magnet 50 with an improved orientation rate of the magnetic powder.

[0105] (13) The blower 10 includes a motor 20 and a fan unit 11 driven by the motor 20 .

[0106] According to the above configuration, blower 10 can preferably blow air by driving fan section 11 with motor 20 having improved performance.

[0107] (14) The refrigeration device includes a motor 20.

[0108] According to the above configuration, the refrigeration apparatus can improve the energy utilization efficiency of the refrigeration apparatus by using the motor 20 with improved performance.

[0109] <Example of change> In addition to the above-described embodiments, the manufacturing method of bonded magnet 50, rotor 40 of motor 20, motor 20, blower 10, and refrigeration device of the present disclosure may also be configured in a form that combines, for example, the modified examples shown below and at least two modified examples that are not mutually contradictory.

[0110] 9, the inner circumferential surface 51B of the first portion 51 may be located radially inward of the inner circumferential surface 52B of the second portion 52. By having the inner circumferential surface 51B of the first portion 51 located radially inward of the inner circumferential surface 52B of the second portion 52, the magnetic powder is oriented in accordance with the shape of the inner circumferential surface 52B of the second portion 52. This improves the orientation rate of the magnetic powder.

[0111] As shown in FIG. 10, bond magnet 50 may be covered with resin 70. Resin 70 covering bond magnet 50 may be the same resin material as the binder of bond magnet 50, or it may be a different resin material. Because bond magnet 50 is covered with resin 70, resin 70 can improve the strength of bond magnet 50. In FIG. 10, the welds in bond magnet 50 and resin 70 are schematically shown by dashed lines. In the circumferential direction of bond magnet 50, the welds in resin 70 are formed so that the positions of the welds in bond magnet 50 are different from the positions of the welds in bond magnet 50. This can improve the strength of bond magnet 50.

[0112] The magnetization step may be omitted. In this case, for example, the bond magnet 50 is magnetized by the magnetic field generation unit 66.

[0113] The motor 20 may be an inner rotor type motor.

[0114] The motor 20 may be used in an outdoor unit of a refrigeration device or a compressor of a refrigeration device.

[0115] The above describes embodiments of the method for manufacturing bonded magnet 50, rotor 40 of motor 20, motor 20, blower 10, and refrigeration device. However, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the method for manufacturing bonded magnet 50, rotor 40 of motor 20, motor 20, blower 10, and refrigeration device as set forth in the claims. [Explanation of symbols]

[0116] 10...blower, 11...fan portion, 20...motor, 30...stator, 40...rotor, 50...bonded magnet, 50A...end surface, 51...first portion, 51A...outer surface, 51B...inner surface, 52...second portion, 52A...outer surface, 52B...inner surface, 53...gate mark, 60...molding mold, 61...mold body, 62...injection port, 63...cavity, 63A...end surface, 63B...inner surface, 63C...outer surface, 64...first region, 65...second region, 66...magnetic field generating portion, 70...resin.

Claims

1. A method for manufacturing a bonded magnet (50), comprising: The method includes an injection step of injecting a bonded magnet material containing magnetic powder into a molding die (60) having a mold body (61) having an injection port (62) and a cylindrical cavity (63) through the injection port (62), The cavity (63) has a first region (64) and a second region (65) in a cross section perpendicular to a cylinder axis direction (CD) of the cavity (63), The second region (65) is a region different from the first region (64) in the circumferential direction of the cavity (63), In the radial direction of the cavity (63), the length of the first region (64) is shorter than the length of the second region (65), The inlet (62) is provided in the first region (64). Manufacturing method of bonded magnets.

2. The molding die (60) further includes a magnetic field generating unit (66) that is arranged on an inner surface (63B) side or an outer surface (63C) side of the cavity (63) in the radial direction and generates a magnetic field within the cavity (63), The magnetic field generating unit (66) has magnetic poles arranged side by side in the circumferential direction, The first region (64) faces the center of the magnetic pole in the radial direction. A method for manufacturing the bonded magnet according to claim 1.

3. In the injection step, the bonded magnet material is injected into the injection port (62) from the cylinder axis direction (CD). The method for manufacturing the bonded magnet according to claim 2.

4. The injection port (62) is provided on an end surface (63A) of the cavity (63) in the cylinder axis direction (CD). The method for manufacturing the bonded magnet according to claim 3.

5. The method further comprises a magnetizing step of magnetizing the bonded magnet (50), The magnetizing step is performed after the injection step. A method for manufacturing the bonded magnet according to claim 1.

6. A rotor (40) of a motor (20), The rotor (40) includes a cylindrical bonded magnet (50), The bonded magnet (50) includes magnetic powder whose length in a second direction perpendicular to the easy axis of magnetization is longer than its length in a first direction along the easy axis of magnetization, The bonded magnet (50) is a polar anisotropic magnet having two or more magnetic poles adjacent to each other in the circumferential direction of the bonded magnet (50), The bonded magnet (50) has a first portion (51) including the magnetic poles and a second portion (52) located midway between the magnetic poles adjacent to each other in the circumferential direction, In the radial direction of the bonded magnet (50), the length of the first portion (51) is shorter than the length of the second portion (52), A gate mark (53) formed by injecting a bonded magnet material is formed in the first portion (51). Rotor.

7. An outer peripheral surface (52A) of the second portion (52) is located outside an outer peripheral surface (51A) of the first portion (51) in the radial direction. The rotor of claim 6.

8. An inner circumferential surface (51B) of the first portion (51) is located more inward than an inner circumferential surface (52B) of the second portion (52) in the radial direction. The rotor of claim 7.

9. In the radial direction, a ratio of the length of the first portion (51) to the length of the second portion (52) is equal to or greater than 0.5 and less than 1.

0. The rotor of claim 6.

10. a first orientation ratio of the magnetic powder in the magnetic pole of the first portion (51) with respect to the radial direction is greater than a second orientation ratio of the magnetic powder in the magnetic pole of the second portion (52) with respect to the circumferential direction; The rotor of claim 6.

11. In the first portion (51), the number of the magnetic particles in a unit volume in which the easy magnetic axes of the magnetic particles are oriented in the radial direction is greater than the number of the magnetic particles in a unit volume in which the easy magnetic axes of the magnetic particles are oriented in the circumferential direction, In the second portion (52), the number of magnetic particles in a unit volume in which the magnetic easy axes of the magnetic particles are oriented in the circumferential direction is greater than the number of magnetic particles in a unit volume in which the magnetic easy axes of the magnetic particles are oriented in the radial direction. The rotor of claim 6.

12. The gate mark (53) is formed on an end surface (50A) of the bonded magnet (50) in the axial direction (AD) of the bonded magnet (50). The rotor of claim 6.

13. The bonded magnet (50) is covered with a resin (70). The rotor of claim 6.

14. A rotor (40) according to any one of claims 6 to 13; a stator (30); Motor.

15. A motor (20) according to claim 14; and a fan unit (11) driven by the motor (20). Blower.

16. A motor (20) according to claim 14, Refrigeration equipment.

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