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

Abstract

In bonded magnets formed by injection molding, there is room for improvement in adjusting the orientation ratio of the magnetic powder. [Solution] A method for manufacturing a bonded magnet, comprising an injection step of injecting 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. 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 injection port 62 is provided in the first region 64.

Description

Technical Field

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

Background Art

[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.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0005] A method for manufacturing a bonded magnet according to a first aspect for solving the above problems includes an injection step of injecting a bonded magnet material containing magnetic powder into a mold having a mold 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. The injection port is provided in the first region.

[0006] According to the above configuration, by injecting bonded magnet material from an injection port provided in the first region, the orientation ratio of magnetic powder along the direction of 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 a first aspect, wherein the mold is further provided with a magnetic field generating unit that is arranged on the inner or outer side of the cavity in the radial direction and generates a magnetic field within the cavity, the magnetic field generating unit has magnetic poles arranged 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 ratio of magnetic powder along the magnetic flux of the magnetic field generating section can be improved.

[0009] The third aspect of the method for manufacturing a bonded magnet is the method for manufacturing a bonded magnet according to the second aspect, wherein in the injection step, the bonded magnet material is injected into the injection port from the direction of the cylindrical axis.

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

[0011] 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 axial direction.

[0012] According to the above configuration, in the injection process, bonded magnets can be suitably formed by injecting bonded magnet material from the end face of the cavity in the cylindrical axis direction.

[0013] The fifth aspect of the method for manufacturing a bonded magnet is the method for manufacturing a bonded magnet according to any one of the first to fourth aspects, further comprising a magnetization step of magnetizing the bonded magnet, wherein the magnetization step is performed after the injection step.

[0014] According to the above configuration, the bonded magnet can be suitably magnetized by the magnetization process.

[0015] The rotor of the motor according to the sixth aspect for solving the above problems 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 midway 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.

[0016] According to the above configuration, the bonded magnet is injection-molded near the first portion containing the magnetic poles. Therefore, the orientation of the magnetic powder in injection molding can be improved.

[0017] In the rotor of the seventh viewpoint, the outer circumferential surface of the second portion is located radially outward from the outer circumferential surface of the first portion in the rotor of the sixth viewpoint.

[0018] According to the above configuration, the magnetic powder is oriented to match the shape of the outer surface of the second part. Therefore, the orientation rate of the magnetic powder can be improved.

[0019] In the rotor of the eighth 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.

[0020] According to the above configuration, the magnetic powder is oriented to match the shape of the inner surface of the second part. Therefore, the orientation rate of the magnetic powder can be improved.

[0021] In the rotor of the ninth aspect, in the rotor of the sixth aspect, 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.

[0022] According to the above configuration, the orientation rate of the magnetic powder can be improved by a shape in which the magnetic powder is preferably oriented easily.

[0023] The rotor of the tenth aspect is the rotor of the sixth aspect, and the first orientation rate of the magnetic powder with respect to the radial direction in the magnetic pole of the first portion is larger than the second orientation rate of the magnetic powder with respect to the circumferential direction in the second portion.

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

[0025] The rotor of the eleventh aspect is the rotor of any one of the sixth to tenth aspects. In the first portion, the number of magnetic powder in the unit volume in which the easy magnetization axis of the magnetic powder faces the radial direction is larger than the number of magnetic powder in the unit volume in which the easy magnetization axis of the magnetic powder faces the circumferential direction. In the second portion, the number of magnetic powder in the unit volume in which the easy magnetization axis of the magnetic powder faces the circumferential direction is larger than the number of magnetic powder in the unit volume in which the easy magnetization axis of the magnetic powder faces the radial direction.

[0026] According to the above configuration, the orientation rate of the magnetic powder can be improved by the easy magnetization axis of the magnetic powder facing a suitable direction.

[0027] The rotor of the twelfth aspect is the rotor of any one of the sixth to eleventh aspects, and the gate mark is formed on the 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] The rotor of the thirteenth aspect is the rotor of any one of the sixth to twelfth aspects, and the bonded magnet is covered with resin.

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

[0031] The motor of the 14th aspect comprises a rotor of any one of the 6th to 13th aspects, and a stator.

[0032] According to the above configuration, the motor's performance can be improved by using a rotor that includes bonded magnets with an improved magnetic particle orientation ratio.

[0033] The blower according to the 15th viewpoint comprises the motor according to the 14th viewpoint and a fan section driven by the motor.

[0034] With the above configuration, the blower can effectively blow air by driving the fan section with a motor with improved performance.

[0035] The refrigeration system of the 16th aspect is equipped with the motor of the 14th aspect.

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

[0037] [Figure 1] This is a schematic diagram of the indoor unit for the refrigeration system of the embodiment. [Figure 2] Figure 1 is a cross-sectional view showing the motor and fan of the indoor unit for a refrigeration system. [Figure 3] Figure 2 is a plan view of the mold for the bonded magnet that will be installed on the rotor of the motor. [Figure 4] This is a cross-sectional view of the mold for a bonded magnet along the line D4-D4 in Figure 3. [Figure 5] This is a cross-sectional view of the mold for a bonded magnet along the line D5-D5 in Figure 4. [Figure 6] Figure 2 is a perspective view of the bonded magnet provided on the rotor of the motor. [Figure 7] Figure 6 is a plan view of the bonded magnet. [Figure 8] Figure 7 is a magnified plan view of a portion of the bonded magnet. [Figure 9] This is a magnified plan view of a portion of the modified bonded magnet. [Figure 10] This is a cross-sectional view of the modified bonded magnet. [Modes for carrying out the invention]

[0038] <Embodiment> Referring to Figures 1 to 8, the manufacturing method of the bonded magnet 50 of the embodiment, the rotor 40 of the motor 20, the motor 20, the blower 10, and the refrigeration device will be described.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 port to the outlet port 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.

[0043] <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.

[0044] 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.

[0045] 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.

[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 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] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

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

[0054] Magnetic powder has an easy magnetization axis. The length of the magnetic powder in a second direction perpendicular to the easy magnetization axis is longer than the length in a first direction along the easy magnetization axis. The magnetic powder has a flattened shape. The magnetic powder is in the form of fine powder or granules. The magnetic powder is either ferrite magnetic powder or rare-earth magnetic powder. Rare-earth magnetic powders include NdFeB-based magnetic powder or SmCo-based magnetic powder.

[0055] Binders such as nylon resin and PPS (Polyphenylene Sulfide) resin are used. Examples of nylon resins include nylon 12, nylon 6, nylon 6,6, nylon 11, nylon 6,12, nylon 6,10, nylon 6,66, and nylon MXD6. Various types of nylon resins may be used individually or in mixtures of multiple types.

[0056] The bonded magnet 50 has a first portion 51 that includes magnetic poles and a second portion 52 that is located midway between adjacent magnetic poles in the circumferential direction. The second portion 52 is a portion of the bonded magnet 50 that is different from the first portion 51 in the circumferential direction. The second portion 52 may be partially provided midway between adjacent magnetic poles in the circumferential direction.

[0057] A gate mark 53 is formed in the first part 51 where bond magnet material has been injected. The gate mark 53 is an injection mark of bond magnet material formed in a position corresponding to the injection port 62 provided in the mold 60, which will be described later. The gate mark 53 is formed on the end face 50A of the bond magnet 50 in the axial direction AD of the bond magnet 50.

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

[0059] 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 greater and less than 1.0.

[0060] The first portion 51 has an outer circumferential surface 51A and an inner circumferential surface 51B. The second portion 52 has an outer circumferential surface 52A and an inner circumferential surface 52B. The outer circumferential surface 52A of the second portion 52 is located further outward than the outer circumferential surface 51A of the first portion 51 in the radial direction of the bonded magnet 50. The outer circumferential surface 52A at the smallest portion of the second portion 52 is located further outward than the outer circumferential surface 51A at the largest portion of the first portion 51 in the radial direction of the bonded magnet 50. The inner circumferential surface 51B of the first portion 51 is continuous with the inner circumferential surface 52B of the second portion 52.

[0061] In this embodiment, orientation means that the easy magnetization axis of the magnetic powder contained in the bonded magnet material is aligned in a predetermined direction. The orientation ratio is defined by the following equation (1) as the average value of the orientation component of each magnetic powder with respect to the predetermined direction.

number

[0062] In equation (1), X is the orientation factor. In equation (1), N is the total number of magnetic particles contained in any given region. In equation (1), θ is the angle between a given direction and the easy magnetization axis of each magnetic particle. Any given region is defined, for example, by the observation range of a scanning electron microscope (SEM).

[0063] 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 magnetic poles of the second part 52 with respect to the circumferential direction. 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 at the second part 52.

[0064] 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.

[0065] <Method for manufacturing bonded magnets> The manufacturing method of the bonded magnet 50 will be described with reference to Figures 3 to 8.

[0066] The bonded magnet 50 is 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 located 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.

[0067] 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.

[0068] 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.

[0069] The mold 60 further comprises 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.

[0070] 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 2 or more even natural poles. The first region 64 faces the center of the magnetic poles in the radial direction of the cavity 63.

[0071] 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.

[0072] 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.

[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 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.

[0074] 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.

[0075] 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 through the runner 68B and the injection port 62.

[0076] 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.

[0077] 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 location where the welds are formed substantially corresponds to the q-axis of the bonded magnet 50.

[0078] 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.

[0079] 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.

[0080] <Operation of the Embodiment> The operation of this embodiment will now be explained. In this embodiment, since the injection port 62 is located in the first region 64, the bonded magnet material flows in a manner that spreads from the first region 64 toward the second region 65 during the injection process. Therefore, the easy magnetization axis of the magnetic powder is oriented in the direction that it spreads from the first region 64 toward the second region 65.

[0081] <Effects of the Embodiment> The effects of the embodiment will be explained. (1) The method for manufacturing the bonded magnet 50 includes an injection step of injecting bonded magnet material containing magnetic powder into a mold 60, which is equipped with 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 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.

[0082] 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.

[0083] (2) The mold 60 is further equipped with a magnetic field generating unit 66 which 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. 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.

[0084] With 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.

[0085] (3) In the injection process, bonded magnet material is injected into the injection port 62 from the cylindrical axis CD.

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

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

[0088] According to 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.

[0089] (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.

[0090] According to the above configuration, the bonded magnet 50 can be suitably magnetized by the magnetization process.

[0091] (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.

[0092] 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 rate of the magnetic powder in injection molding can be improved.

[0093] (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.

[0094] According to the above configuration, the magnetic powder is oriented to match the shape of the outer surface 52A of the second part 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 part 51 to the length of the second part 52 is 0.5 or more and less than 1.0.

[0096] According to the above configuration, the orientation rate of magnetic powder can be improved by using a shape that facilitates the orientation of magnetic powder.

[0097] (9) The first orientation ratio of magnetic particles in the radial direction at the magnetic poles of the first part 51 is greater than the second orientation ratio of magnetic particles in the circumferential direction at the second part 52.

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

[0099] (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.

[0100] According to the above configuration, the orientation rate of the magnetic powder can be improved by aligning the easy magnetization axis of the magnetic powder in a suitable direction.

[0101] (11) 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.

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

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

[0104] According to the above configuration, the motor 20 can improve its performance by including a rotor 40 that contains a bonded magnet 50 with an improved magnetic particle orientation ratio.

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

[0106] With the above configuration, the blower 10 can effectively blow air by driving the fan section 11 with the improved performance motor 20.

[0107] (14) The refrigeration unit is equipped with a motor 20.

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

[0109] <Example of changes> The manufacturing method for the bonded magnet 50, the rotor 40 of the motor 20, the motor 20, the blower 10, and the refrigeration device of the present disclosure may also be, in addition to the embodiments described above, for example, the modified examples shown below and a combination of at least two mutually non-inconsistent modified examples.

[0110] As shown in Figure 9, the inner surface 51B of the first portion 51 may be located radially inward from the inner surface 52B of the second portion 52. By having the inner surface 51B of the first portion 51 located radially inward from the inner surface 52B of the second portion 52, the magnetic particles are oriented to conform to the shape of the inner surface 52B of the second portion 52. Therefore, the orientation rate of the magnetic particles can be improved.

[0111] 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 welds of the resin 70 is formed to be different from the position of the welds of the bonded magnet 50. This can improve the strength of the bonded magnet 50.

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

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

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

[0115] The above describes the manufacturing method of the bonded magnet 50, the rotor 40 of the motor 20, the motor 20, the blower 10, and the embodiment of the refrigeration device. It should 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 device as described in the claims. [Explanation of Symbols]

[0116] 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), A molding die (60) is provided with a mold body (61) having an injection port (62) and a cylindrical cavity (63), and an injection step is provided in which a bonded magnet material containing magnetic powder is injected 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 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), A method for manufacturing bonded magnets.

2. The mold (60) is further provided with a magnetic field generating unit (66) which is positioned 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) has magnetic poles arranged in the circumferential direction, The first region (64) is, in the radial direction, facing the center of the magnetic pole, A method for manufacturing a bonded magnet according to claim 1.

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

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

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

6. The rotor (40) of the motor (20), The rotor (40) 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 a polar 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) including the 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) is formed in the first portion (51) where bonded magnet material is injected. Rotor.

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

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

9. 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. The rotor according to claim 6.

10. 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). The rotor according to claim 6.

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

12. 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). The rotor according to claim 6.

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

14. A rotor (40) according to any one of claims 6 to 13, A stator (30) and a stator (30) are provided. Motor.

15. The motor (20) described in claim 14, The system comprises a fan section (11) driven by the motor (20), Blower.

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

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