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

Abstract

This method for manufacturing a bonded magnet comprises an injecting step for injecting a bonded magnet material containing magnetic powder from injection ports (62) into a molding die (60) provided with a die main body (61) that includes the injection ports (62) and a cylindrical cavity (63). The cavity (63) has first regions (64) and second regions (65) in a cross section orthogonal to a cylinder axis direction (CD) of the cavity (63). The second regions (65) are regions that are different from the first regions (64) in the circumferential direction of the cavity (63). In the radial direction of the cavity (63), the length of each first region (64) is less than the length of each second region (65). The injection ports (62) are provided in the first regions (64).

Description

Method for manufacturing bonded magnet, rotor, motor, blower, and refrigeration device

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

[0002] Patent Document 1 discloses an anisotropic bonded magnet. In the bonded magnet disclosed in Patent Document 1, the orientation and magnetization direction of magnetic powder are controlled by an orientation magnet provided on the inner circumference of an annular bonded magnet.

[0003] Japanese Unexamined Patent Application Publication No. 2018-142635

[0004] In Patent Document 1, the orientation of magnetic powder in injection molding is not considered. In a bonded magnet molded by injection molding, there is room for improvement in adjusting the orientation rate of magnetic powder.

[0005] A method for manufacturing a bonded magnet according to a first aspect of the present disclosure includes an injection step of injecting a bonded magnet material containing magnetic powder into a molding die including a die body having an injection port and a cylindrical cavity from the injection port. The cavity has a first region and a second region in a cross section orthogonal to the axial direction of the cavity cylinder. The second region is a region different from the first region in the circumferential direction of the cavity. In the radial direction of the cavity, the length of the first region is shorter than the length of the second region, and the injection port is provided in the first region.

[0006] According to the above configuration, by injecting the bonded magnet material from the injection port provided in the first region, the orientation rate of magnetic powder along the direction spreading from the first region to the second region can be improved.

[0007] A method for manufacturing a bonded magnet according to a second aspect is the method for manufacturing a bonded magnet according to the first aspect, wherein the molding die is disposed on the inner surface side or the outer surface side of the cavity in the radial direction, and further includes a magnetic field generating unit that generates a magnetic field in the cavity. The magnetic field generating unit has 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, since the injection port is provided in a first region facing the center of the magnetic pole of the magnetic field generating section in the radial direction, the orientation rate of the magnetic powder along the magnetic flux of the magnetic field generating section can be improved. The manufacturing method of a bonded magnet according to the third aspect is that, in the manufacturing method of a bonded magnet according to the second aspect, the bonded magnet material is injected into the injection port from the direction of the cylindrical axis in the injection step.

[0009] According to the above configuration, a bonded magnet can be suitably formed by injecting the bonded magnet material from the direction of the cylindrical axis. The fourth aspect of the method for manufacturing a bonded magnet is the method for manufacturing a bonded magnet according to the third aspect, wherein the injection port is provided on the end face of the cavity in the direction of the cylindrical axis.

[0010] According to the above configuration, in the injection step, a bonded magnet can be suitably formed by injecting the bonded magnet material from the end face of the cavity in the direction of the cylindrical axis. The method for manufacturing a bonded magnet according to the fifth aspect further comprises a magnetization step of magnetizing the bonded magnet in any one of the methods for manufacturing a bonded magnet according to the first to fourth aspects, wherein the magnetization step is performed after the injection step.

[0011] According to the above configuration, the bonded magnet can be suitably magnetized by the magnetization process. A rotor of a motor according to a sixth aspect of one aspect of the present disclosure comprises a cylindrical bonded magnet, the bonded magnet contains magnetic powder whose length in a second direction perpendicular to the easy magnetization axis is longer than its length in a first direction along the easy magnetization axis, the bonded magnet is an anisotropic magnet having two or more adjacent magnetic poles in the circumferential direction of the bonded magnet, the bonded magnet has a first portion containing the magnetic poles and a second portion located between the adjacent magnetic poles in the circumferential direction, the length of the first portion is shorter than the length of the second portion in the radial direction of the bonded magnet, and a gate mark formed in the first portion where the bonded magnet material has been injected.

[0012] According to the above configuration, the bonded magnet is injection-molded near the first portion containing the magnetic poles. Therefore, the orientation ratio of the magnetic powder in injection molding can be improved. In the rotor of the seventh view, in the rotor of the sixth view, the outer circumferential surface of the second portion is located radially outward from the outer circumferential surface of the first portion.

[0013] According to the above configuration, the magnetic particles are oriented to match the shape of the outer circumferential surface of the second portion. Therefore, the orientation rate of the magnetic particles can be improved. In the rotor of the eighth viewpoint, in the rotor of the seventh viewpoint, the inner circumferential surface of the first portion is located inward in the radial direction compared to the inner circumferential surface of the second portion.

[0014] According to the above configuration, the magnetic particles are oriented to match the shape of the inner circumferential surface of the second part. Therefore, the orientation rate of the magnetic particles can be improved. In the rotor of the ninth view, in the rotor of the sixth view, the ratio of the length of the first part to the length of the second part in the radial direction is 0.5 or more and less than 1.0.

[0015] According to the above configuration, the orientation rate of the magnetic powder can be improved by a shape that facilitates the orientation of the magnetic powder. In the rotor of the tenth aspect, in the rotor of the sixth aspect, the first orientation rate of the magnetic powder with respect to the radial direction in the magnetic pole of the first part is greater than the second orientation rate of the magnetic powder with respect to the circumferential direction in the second part.

[0016] According to the above configuration, the orientation ratio of magnetic particles in the gate trace can be improved. In the rotor of the 11th aspect, in any one rotor of the 6th to 10th aspects, in the first part, the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented radially is greater than the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented circumferentially, and in the second part, the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented circumferentially is greater than the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented radially.

[0017] According to the above configuration, the orientation ratio of the magnetic powder can be improved by aligning the easy magnetization axis of the magnetic powder in a suitable direction. In the rotor of the twelfth view, in any one of the rotors of the sixth to eleventh views, the gate mark is formed on the end face of the bonded magnet in the axial direction of the bonded magnet.

[0018] According to the above configuration, bonded magnets can be formed by injection molding from the axial direction. In the rotor of the 13th view, the bonded magnet is covered with resin in any one of the rotors from the 6th to the 12th views.

[0019] According to the above configuration, the strength of the bonded magnet can be improved by the resin. The motor of the 14th aspect comprises a rotor and a stator, which are one of the rotors of the 6th to 13th aspects.

[0020] According to the above configuration, the motor's performance can be improved by a rotor containing bonded magnets with an improved magnetic particle orientation ratio. The blower according to the 15th aspect comprises the motor according to the 14th aspect and a fan section driven by the motor.

[0021] According to the above configuration, the blower can effectively blow air by driving the fan section with a motor with improved performance. The refrigeration device according to the 16th aspect is equipped with the motor according to the 14th aspect.

[0022] According to the above configuration, the energy utilization efficiency of the refrigeration system can be improved by using a motor with improved performance.

[0023] This is a schematic diagram of the indoor unit for the refrigeration system of the embodiment. This is a cross-sectional view showing the motor and fan of the indoor unit for the refrigeration system of Figure 1. This is a plan view of the mold for the bonded magnet provided on the rotor of the motor of Figure 2. This is a cross-sectional view of the mold for the bonded magnet along the line D4-D4 of Figure 3. This is a cross-sectional view of the mold for the bonded magnet along the line D5-D5 of Figure 4. This is a perspective view of the bonded magnet provided on the rotor of the motor of Figure 2. This is a plan view of the bonded magnet of Figure 6. This is an enlarged plan view of a part of the bonded magnet of Figure 7. This is an enlarged plan view of a part of the bonded magnet of the modified example. This is a cross-sectional view of the bonded magnet of the modified example.

[0024] <Embodiment> Referring to Figures 1 to 8, the manufacturing method of the bonded magnet 50 according to the embodiment, the rotor 40 of the motor 20, the motor 20, the blower 10, and the refrigeration device will be described.

[0025] The refrigeration system includes a motor 20. Examples of refrigeration systems include an air conditioner, a water heater, a chiller unit, and a cooling device for cooling the air inside the storage area. The air conditioner is either a dedicated refrigeration unit, a dedicated heating unit, or a heating and cooling unit that can switch between cooling and heating. The air inside the storage area is the air inside refrigerators, freezers, display cases, and containers. In this embodiment, the refrigeration system will be described as an air conditioner.

[0026] Figure 1 shows the indoor unit 1 of an air conditioner. In this embodiment, the motor 20 is provided in the indoor unit 1. The indoor unit 1 is, for example, a wall-mounted type that is attached to the wall of a room. The indoor unit 1 is connected to the outdoor unit of the air conditioner by refrigerant piping.

[0027] The indoor unit 1 includes a heat exchanger that exchanges heat with the air drawn in from the intake port, a blower 10, and a casing 2 that supports the heat exchanger and the blower 10. The heat exchanger and the blower 10 are arranged in the internal space of the casing 2.

[0028] The blower 10 comprises a motor 20 and a fan unit 11 driven by the motor 20. The fan unit 11 is located downstream of the heat exchanger in the airflow path from the intake to the 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 turbo fans and sirocco fans. In this embodiment, the fan unit 11 is a cross-flow fan.

[0029] <Motor> As shown in Figure 2, the motor 20 is, for example, an outer rotor type motor. The motor 20 comprises a rotor 40 and a stator 30.

[0030] The stator 30 comprises a stator body 30A, a stator core 31, and a coil 32. These components constituting the stator 30 are integrally molded using resin molding. The stator body 30A is positioned radially inward of the rotor 40.

[0031] The stator core 31 is formed by laminating conductive steel plates. The steel plates are soft magnetic materials. The stator core 31 has multiple teeth. The coil 32 is formed by winding wire around the teeth of the stator core 31. The winding wire is copper wire or aluminum wire. The winding wire is covered with an insulating material such as enamel resin.

[0032] 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 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.

[0033] The stator 30 further includes a cylindrical stator outer periphery 33 and a connecting portion 34 that connects the stator body 30A and the stator outer periphery 33. The stator outer periphery 33 is provided on the radially outer side of the stator body 30A. The connecting portion 34 connects the stator body 30A and the stator outer periphery 33. A housing chamber 35 is formed between the stator body 30A and the stator outer periphery 33. The housing chamber 35 is configured in an annular shape when viewed from the axial direction AD of the bonded magnet 50.

[0034] The motor 20 further comprises a rotating shaft 21. The stator 30 has a through hole 36 in which the rotating shaft 21 is positioned. At least one bearing 22 is positioned in the through hole 36. The bearing 22 supports the rotating shaft 21 so that it 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 two bearings 22 so as to be rotatable relative to the stator 30.

[0035] The rotor 40 is equipped with a cylindrical bonded magnet 50. At least a portion of the bonded magnet 50 is placed in the housing chamber 35. The bonded magnet 50 is positioned radially outward of the stator body 30A. The bonded magnet 50 is positioned radially inward of the outer circumference 33 of the stator.

[0036] The rotor 40 further comprises a cover member 41. The bonded magnet 50 is formed separately from the cover member 41 and is attached to the cover member 41 so as to rotate integrally with the cover member 41. The cover member 41 is provided at one end of the bonded magnet 50 in the axial direction AD of the bonded magnet 50. The bonded magnet 50 is attached to the cover member 41, for example, by mounting claws. The bonded magnet 50 may also be attached to the cover member 41 by adhesive or the like.

[0037] The cover member 41 is formed from a resin material. Preferably, the resin material forming the cover member 41 is the same as the resin material used for the binder in the bonded magnet 50. However, the resin material forming the cover member 41 may be different from the resin material used for the binder in the bonded magnet 50.

[0038] The cover member 41 has an axial cover portion 41A and a radial cover portion 41B extending from the axial cover portion 41A in the axial direction AD. The axial cover portion 41A is connected to one end of the bonded magnet 50 in the axial direction AD. The radial cover portion 41B covers at least partially the radially outer side of the bonded magnet 50 and the stator 30.

[0039] <Bonded Magnet> The bonded magnet 50 will be described with reference to Figures 6 to 8. The bonded magnet 50 is a polar anisotropic magnet having two or more adjacent magnetic poles in the circumferential direction of the bonded magnet 50. The bonded magnet 50 is formed from a bonded magnet material. The bonded magnet material includes magnetic powder and a binder.

[0040] The magnetic powder has an easy magnetization axis. The length of the magnetic powder in the second direction perpendicular to the easy magnetization axis is longer than the length in the first direction along the easy magnetization axis. The magnetic powder has a flat shape. The magnetic powder is in the form of fine powder or grains. The magnetic powder is ferrite magnetic powder or rare earth-based magnetic powder. The rare earth-based magnetic powder includes NdFeB-based magnetic powder or SmCo-based magnetic powder.

[0041] Binders such as nylon resin and PPS (Poly Phenylene Sulfide) resin are used. Examples of nylon resin include 12 nylon, 6 nylon, 6,6 nylon, 11 nylon, 6,12 nylon, 6,10 nylon, 6,66 nylon, nylon MXD6, etc. Various nylon resins may be used alone or in combination of multiple types.

[0042] The bonded magnet 50 has a first portion 51 including magnetic poles and a second portion 52 located in the middle of adjacent magnetic poles in the circumferential direction. The second portion 52 is a portion different from the first portion 51 in the circumferential direction of the bonded magnet 50. The second portion 52 may be partially provided in the middle of adjacent magnetic poles in the circumferential direction.

[0043] A gate mark 53 into which a bonded magnet material is injected is formed in the first portion 51. The gate mark 53 is an injection mark of the bonded magnet material formed corresponding to the position of an injection port 62 provided in a mold 60 described later. The gate mark 53 is formed on the end face 50A of the bonded magnet 50 in the axial direction AD of the bonded magnet 50.

[0044] The d-axis shown in FIG. 8 is an axis passing through the center of the magnetic poles of the bonded magnet 50. The q-axis shown in FIG. 8 is an axis electrically and magnetically orthogonal to the d-axis. The d-axis is located at the center of the first portion 51 in the circumferential direction. The q-axis is located at the center of the second portion 52 in the circumferential direction. At least a part of the gate mark 53 passes through, for example, the d-axis.

[0045] 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. In the radial direction of the bonded magnet 50, the length of the maximum portion of the first portion 51 is shorter than the length of the minimum portion of the second portion 52. In the radial direction of the bonded magnet 50, the ratio of the length of the maximum portion of the first portion 51 to the length of the minimum portion of the second portion 52 is 0.5 or more and less than 1.0.

[0046] The first portion 51 has an outer peripheral surface 51A and an inner peripheral surface 51B. The second portion 52 has an outer peripheral surface 52A and an inner peripheral surface 52B. The outer peripheral surface 52A of the second portion 52 is located outside the outer peripheral surface 51A of the first portion 51 in the radial direction of the bonded magnet 50. The outer peripheral surface 52A in the minimum portion of the second portion 52 is located outside the outer peripheral surface 51A in the maximum portion of the first portion 51 in the radial direction of the bonded magnet 50. The inner peripheral surface 51B of the first portion 51 is continuous with the inner peripheral surface 52B of the second portion 52.

[0047] In the present embodiment, "orientation" means that the easy magnetization axis of the magnetic powder contained in the bonded magnet material is along a predetermined direction. The orientation ratio is defined by the following formula (1) as the average value of the orientation components of each magnetic powder with respect to the predetermined direction.

[0048]

[0049] In formula (1), X is the orientation ratio. In formula (1), N is the total number of magnetic powders contained in an arbitrary region. In formula (1), θ is the angle formed by the predetermined direction and the easy magnetization axis of each magnetic powder. The arbitrary region is set, for example, by the observation range of a scanning electron microscope (SEM: Scanning Electron Microscope).

[0050] The first orientation ratio of the magnetic particles in the magnetic poles of the bonded magnet 50 with respect to the radial direction is greater than the second orientation ratio of the magnetic particles in the circumferential direction in the second part 52. The magnetic flux of the bonded magnet 50 at the magnetic poles is substantially along the radial direction of the bonded magnet 50. Therefore, the closer to the magnetic poles of the bonded magnet 50, the more the easy magnetization axis of the magnetic particles aligns with the magnetic flux of the magnetic field generating unit 66. The first orientation ratio is calculated, for example, as the average value of the orientation components of each magnetic particle with respect to the radial direction at the magnetic poles of the first part 51. The second orientation ratio is calculated as the average value of the orientation components of each magnetic particle with respect to the circumferential direction in the second part 52.

[0051] In the first part 51, the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented radially to the bonded magnet 50 is greater than the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented circumferentially. In the second part 52, the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented circumferentially is greater than the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented radially to the bonded magnet 50.

[0052] <Method for Manufacturing Bonded Magnets> The method for manufacturing bonded magnets 50 will be described with reference to Figures 3 to 8. Bonded magnets 50 are formed by a mold 60. The mold 60 comprises a mold body 61. The mold body 61 has an injection port 62 and a cylindrical cavity 63. The injection port 62 is circular. The injection port 62 is provided at the end face 63A of the cavity 63 in the direction CD in the cylindrical axis direction. The end face 63A of the cavity 63 in the direction CD in the cylindrical axis direction is annular.

[0053] The cavity 63 has a first region 64 and a second region 65 in a cross section perpendicular to the cylindrical axis 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.

[0054] At least a portion of the inlet 62 is provided in the first region 64. In this embodiment, the entire inlet 62 is provided in the first region 64. In the circumferential direction of the cavity 63, the length of the first region 64 is greater than or equal to the length of the inlet 62.

[0055] The molding die 60 further includes a magnetic field generating unit 66 that is positioned on the inner side 63B or the outer side 63C of the cavity 63 in the radial direction and generates a magnetic field within the cavity 63. In this embodiment, the magnetic field generating unit 66 is positioned on the inner side 63B of the cavity 63. The magnetic field generating unit 66 has magnetic poles arranged side by side in the circumferential direction. On the outer circumference of the magnetic field generating unit 66, the south poles and north poles are arranged alternately in the circumferential direction.

[0056] The number of magnetic poles of the bonded 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 as many as two or more even natural poles. The first region 64 faces the center of the magnetic poles in the radial direction of the cavity 63.

[0057] The cavity 63 is composed of alternating first regions 64 and second regions 65. 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. In the radial direction of the cavity 63, the length of the maximum portion of the first region 64 is shorter than the length of the minimum portion of the second region 65. In the radial direction of the cavity 63, the ratio of the length of the minimum portion of the first region 64 to the length of the maximum portion of the second region 65 is 0.5 or greater and less than 1.0.

[0058] The first region 64 has an outward surface 64A and an inward surface 64B. In the radial direction of the cavity 63, the distance from each end of the outward surface 64A of the first region 64 to the magnetic pole is greater than or equal to the distance from the middle portion of the outward surface 64A of the first region 64 to the magnetic pole. In the radial direction of the cavity 63, the outward surface 64A of the first region 64 curves from the middle portion of the outward surface 64A of the first region 64 toward each end of the outward surface 64A of the first region 64.

[0059] 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 inward from the rest 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 inlet 62 is shorter than the distance from the rest of the outer surface 65A of the second region 65 to the inlet 62. The outer surface 65A of the second region 65 curves further 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.

[0060] The outer surface 65A of the second region 65 is located outside the outer surface 64A of the first region 64 in the radial direction of the cavity 63. The outer surface 65A of the smallest part of the second region 65 is located outside the outer surface 64A of the largest part of the first region 64 in the radial direction of the cavity 63. In this embodiment, the cavity 63 has a petal shape. The cavity 63 has a shape that follows the flow of magnetic powder of the bonded magnet material. The cavity 63 has a shape such that the first region 64 is smoothly connected to the second region 65. The cavity 63 has a shape such that the width in the radial direction increases monotonically from the first region 64 to the second region 65. The cavity 63 has a shape such that the width in the radial direction decreases monotonically from the second region 65 to the first region 64.

[0061] The mold 60 includes a movable part 68 configured to be movable relative to the mold body 61. The movable part 68 has an injection port 68A and a runner 68B. Bonded magnet material containing magnetic powder is injected into the injection port 68A. The runner 68B is arranged on the movable part 68 so as to spread radially. The bonded magnet material injected from the injection port 68A is injected into the cavity 63 via the runner 68B and the injection port 62.

[0062] The manufacturing method for the bonded magnet 50 includes an injection step in which bonded magnet material containing magnetic powder is injected into a mold 60 through an injection port 62. The injection step is a step for injection molding the bonded magnet 50. In the injection step, the bonded magnet material is injected into the injection port 62 from the cylindrical axis direction CD. In the injection step, once the bonded magnet material is injected from the injection port 68A, it is injected through the runner 68B into the cavity 63 from the injection port 62.

[0063] During the injection process, the bonded magnet material flows downward from the injection port 62 and expands circumferentially, filling the cavity 63. The bonded magnet material injected from the injection port 62 flows so as to expand from the first region 64 to the second region 65, and the easy magnetization axis of the magnetic powder is oriented in the direction of expansion from the first region 64 to the second region 65. The arrows in Figure 5 indicate the flow of the bonded magnet material. Welds are formed where the bonded magnet material injected from each injection port 62 comes into contact with each other. The positions where the welds are formed substantially correspond to the q-axis of the bonded magnet 50.

[0064] The manufacturing method for the bonded magnet 50 further includes a separation step in which the movable part 68 is moved away from the mold body 61. The separation step is performed after the injection step is completed and after the bonded magnet material has hardened. The separation step separates the bonded magnet material in the cavity 63 from the bonded magnet material in the runner 68B.

[0065] The method for manufacturing the bonded magnet 50 further comprises an extraction step in which the bonded magnet 50 is removed from the cavity 63. The method for manufacturing the bonded magnet 50 further comprises a magnetization step in which the bonded magnet 50 is magnetized. The magnetization step is performed after the injection step. Preferably, the magnetization step is performed after the extraction step.

[0066] <Operation of the Embodiment> The operation of this embodiment will now be described. In this embodiment, since the injection port 62 is located in the first region 64, during the injection process, the bonded magnet material flows in a manner that spreads from the first region 64 toward the second region 65. Therefore, the easy magnetization axis of the magnetic powder is oriented in the direction of spreading from the first region 64 toward the second region 65.

[0067] <Effects of the Embodiment> The effects of the embodiment will be described. (1) The manufacturing method of the bonded magnet 50 includes an injection step of injecting bonded magnet material containing magnetic powder into a mold 60 which has 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 the cylindrical axis direction CD of the cavity 63. The second region 65 is a different region 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.

[0068] According to the above configuration, by injecting bonded magnet material from the injection port 62 provided in the first region 64, the orientation ratio of magnetic powder along the direction of spreading from the first region 64 toward the second region 65 can be improved.

[0069] (2) The mold 60 is further provided with a magnetic field generating unit 66 which is located on the inner side 63B or the outer side 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 arranged in the circumferential direction. The first region 64 faces the center of the magnetic poles in the radial direction.

[0070] According to the above configuration, since 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, the orientation ratio of the magnetic powder along the magnetic flux of the magnetic field generating unit 66 can be improved.

[0071] (3) In the injection process, the bonded magnet material is injected into the injection port 62 from the cylindrical axis CD. With the above configuration, the bonded magnet 50 can be suitably formed by injecting the bonded magnet material from the cylindrical axis CD.

[0072] (4) The injection port 62 is provided on the end face 63A of the cavity 63 in the cylindrical axis direction CD. With the above configuration, in the injection process, the bonded magnet 50 can be suitably formed by injecting the bonded magnet material from the end face 63A of the cavity 63 in the cylindrical axis direction CD.

[0073] (5) The method for manufacturing the bonded magnet 50 further comprises a magnetization step of magnetizing the bonded magnet 50. The magnetization step is performed after the injection step. With the above configuration, the bonded magnet 50 can be suitably magnetized by the magnetization step.

[0074] (6) The rotor 40 of the motor 20 is equipped with a cylindrical bonded magnet 50. The bonded magnet 50 contains magnetic powder whose length in a second direction perpendicular to the easy magnetization axis is longer than its length in a first direction along the easy magnetization axis. The bonded magnet 50 is an anisotropic magnet having two or more adjacent magnetic poles in the circumferential direction of the bonded magnet 50. The bonded magnet 50 has a first portion 51 containing magnetic poles and a second portion 52 located midway between 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 into which the bonded magnet material has been injected is formed in the first portion 51.

[0075] According to the above configuration, the bonded magnet 50 is injection molded near the first portion 51 which includes the magnetic poles. Therefore, the orientation ratio of the magnetic powder in injection molding can be improved. (7) The outer circumferential surface 52A of the second portion 52 is located radially outward from the outer circumferential surface 51A of the first portion 51.

[0076] According to the above configuration, the magnetic powder is oriented to match the shape of the outer surface 52A of the second portion 52. Therefore, the orientation rate of the magnetic powder can be improved. (8) In the radial direction, the ratio of the length of the first portion 51 to the length of the second portion 52 is 0.5 or more and less than 1.0.

[0077] According to the above configuration, the orientation rate of the magnetic powder can be improved by a shape that facilitates the orientation of the magnetic powder. (9) The first orientation rate of the magnetic powder in the radial direction at the magnetic pole of the first portion 51 is greater than the second orientation rate of the magnetic powder in the circumferential direction at the second portion 52.

[0078] According to the above configuration, the orientation ratio of magnetic particles in the gate trace 53 can be improved. (10) In the first part 51, the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented radially is greater than the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented circumferentially. In the second part 52, the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented circumferentially is greater than the number of magnetic particles in a unit volume where the easy magnetization axis of the magnetic particles is oriented radially.

[0079] According to the above configuration, the orientation of the magnetic powder can be improved by aligning the easy magnetization axis of the magnetic powder in a suitable direction. (11) The gate marks 53 are formed on the end face 50A of the bonded magnet 50 in the axial direction AD of the bonded magnet 50.

[0080] According to the above configuration, the bonded magnet 50 can be formed by injection molding from the axial direction AD. (12) The motor 20 comprises a rotor 40 and a stator 30.

[0081] According to the above configuration, the motor 20 can improve its performance with a rotor 40 that includes a bonded magnet 50 in which the orientation ratio of magnetic powder is improved. (13) The blower 10 comprises a motor 20 and a fan section 11 driven by the motor 20.

[0082] According to the above configuration, the blower 10 can blow air effectively by driving the fan section 11 with the improved performance motor 20. (14) The refrigeration system is equipped with the motor 20.

[0083] According to the above configuration, the refrigeration system can improve its energy utilization efficiency with the improved performance of the motor 20. <Examples of modifications> The manufacturing method of the bonded magnet 50, the rotor 40 of the motor 20, the motor 20, the blower 10, and the refrigeration system of this disclosure may be, in addition to the above embodiments, for example, the modified examples shown below and a combination of at least two mutually non-contradictory modified examples.

[0084] As shown in Figure 9, the inner circumferential surface 51B of the first portion 51 may be located radially inward from 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 from the inner circumferential surface 52B of the second portion 52, the magnetic particles are oriented to match the shape of the inner circumferential surface 52B of the second portion 52. Therefore, the orientation rate of the magnetic particles can be improved.

[0085] As shown in Figure 10, the bonded magnet 50 may be covered with resin 70. The resin 70 covering the bonded magnet 50 may be the same resin material as the binder of the bonded magnet 50, or it may be a different resin material. Because the bonded magnet 50 is covered with resin 70, the strength of the bonded magnet 50 can be improved by the resin 70. In Figure 10, the welds of the bonded magnet 50 and the resin 70 are schematically shown by dashed lines. In the circumferential direction of the bonded magnet 50, the position of the resin 70 welds is formed to be different from the position of the welds of the bonded magnet 50. This improves the strength of the bonded magnet 50.

[0086] - The magnetization process may be omitted. In this case, for example, the bonded magnet 50 is magnetized by the magnetic field generating unit 66. - The motor 20 may be an inner rotor type motor.

[0087] The motor 20 may be used in an outdoor unit for a refrigeration system or as a compressor for a refrigeration system. The manufacturing method of the bonded magnet 50, the rotor 40 of the motor 20, the motor 20, the blower 10, and embodiments of the refrigeration system have been described above, but it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the manufacturing method of the bonded magnet 50, the rotor 40 of the motor 20, the motor 20, the blower 10, and the refrigeration system as described in the claims.

[0088] 10... Blower, 11... Fan section, 20... Motor, 30... Stator, 40... Rotor, 50... Bonded magnet, 50A... End face, 51... First part, 51A... Outer surface, 51B... Inner surface, 52... Second part, 52A... Outer surface, 52B... Inner surface, 53... Gate mark, 60... Molding die, 61... Mold body, 62... Injection port, 63... Cavity, 63A... End face, 63B... Inner surface, 63C... Outer surface, 64... First region, 65... Second region, 66... ​​Magnetic field generating section, 70... Resin.

Claims

1. A method for manufacturing a bonded magnet (50), comprising an injection step of injecting a bonded magnet material containing magnetic powder into a mold (60) having a mold body (61) having an injection port (62) and a cylindrical cavity (63) through the injection port (62), wherein 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 different region from the first region (64) in the circumferential direction of the cavity (63), the length of the first region (64) is shorter than the length of the second region (65) in the radial direction of the cavity (63), and the injection port (62) is provided in the first region (64).

2. The molding die (60) further comprises a magnetic field generating unit (66) which is arranged on the inner side (63B) or outer side (63C) of the cavity (63) in the radial direction and generates a magnetic field within the cavity (63), the magnetic field generating unit (66) having magnetic poles arranged in the circumferential direction, and the first region (64) facing the center of the magnetic poles in the radial direction, the method for manufacturing a bonded magnet according to claim 1.

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

4. The method for manufacturing a bonded magnet according to claim 3, wherein the injection port (62) is provided on the end face (63A) of the cavity (63) in the cylindrical axis direction (CD).

5. A method for manufacturing a bonded magnet according to any one of claims 1 to 4, further comprising a magnetization step of magnetizing the bonded magnet (50), wherein the magnetization step is performed after the injection step.

6. A rotor (40) of a motor (20), wherein the rotor (40) comprises a cylindrical bonded magnet (50), the bonded magnet (50) contains magnetic powder whose length in a second direction perpendicular to the easy magnetization axis is longer than its length in a first direction along the easy magnetization axis, the bonded magnet (50) is an anisotropic magnet having two or more adjacent magnetic poles in the circumferential direction of the bonded magnet (50), the bonded magnet (50) comprises a first portion (51) containing the magnetic poles and a second portion (52) located midway between the adjacent magnetic poles in the circumferential direction, the length of the first portion (51) is shorter than the length of the second portion (52) in the radial direction of the bonded magnet (50), and a gate mark (53) formed in the first portion (51) by the injection of bonded magnet material.

7. The rotor according to claim 6, wherein the outer circumferential surface (52A) of the second portion (52) is located outside the outer circumferential surface (51A) of the first portion (51) in the radial direction.

8. The rotor according to claim 7, wherein the inner circumferential surface (51B) of the first portion (51) is located inward in the radial direction than the inner circumferential surface (52B) of the second portion (52).

9. The rotor according to claim 6, wherein, in the radial direction, the ratio of the length of the first portion (51) to the length of the second portion (52) is 0.5 or more and less than 1.

0.

10. The rotor according to claim 6, wherein the first orientation ratio of the magnetic particles in the radial direction at the magnetic pole of the first portion (51) is greater than the second orientation ratio of the magnetic particles in the circumferential direction at the second portion (52).

11. The rotor according to any one of claims 6 to 10, wherein in the first portion (51), the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented radially is greater than the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented circumferentially, and in the second portion (52), the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented circumferentially is greater than the number of magnetic particles in a unit volume in which the easy magnetization axis of the magnetic particles is oriented radially.

12. The rotor according to any one of claims 6 to 11, wherein the gate mark (53) is formed on the end face (50A) of the bonded magnet (50) in the axial direction (AD) of the bonded magnet (50).

13. The rotor according to any one of claims 6 to 12, wherein the bonded magnet (50) is covered with resin (70).

14. A motor comprising a rotor (40) and a stator (30) as described in any one of claims 6 to 13.

15. A blower comprising a motor (20) as described in claim 14, and a fan section (11) driven by the motor (20).

16. A refrigeration apparatus comprising the motor (20) described in claim 14.

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