Permanent magnet manufacturing device

Abstract

A permanent magnet manufacturing apparatus includes a compression molding mechanism and a magnetic field generating mechanism. The compression molding mechanism includes a pair of punches facing each other and a cylindrical die into which the pair of punches are inserted. The magnetic field generating mechanism includes a pair of coils. The compression molding mechanism is positioned between the pair of coils. Raw material containing magnet powder is supplied to the die. A magnetic field generated by at least one coil is applied to the raw material, and the raw material within the die is compressed using the pair of punches. The direction of the magnetic field applied to the raw material changes by at least one operation selected from the group consisting of movement of the entire magnetic field generating mechanism, rotation of the entire magnetic field generating mechanism, and rotation of at least one coil.

Description

Technical Field

[0001] The invention relates to a manufacturing device for a permanent magnet. Background Art

[0002] In the manufacture of anisotropic permanent magnets such as bonded magnets and sintered magnets, a raw material containing magnet powder (a plurality of magnet particles formed by a permanent magnet) is supplied to a mold. A magnetic field generated by a coil is applied to the raw material in the mold, and the mold is used to compress the raw material, thereby forming a compact from the raw material. Each magnet particle in the compact (the magnetic domain within each magnet particle) is magnetized and oriented along the magnetic field. (See Patent Documents 1 and 2 below.) For example, in a conventional method for manufacturing a permanent magnet, the mold is configured so that the portion with a high density of magnetic flux (magnetic lines of force) in the magnetic field passes through the raw material in the mold, and a magnetic field parallel to or perpendicular to the direction of pressurization (compression) of the raw material is applied to the raw material in the mold. As a result, the easy axis of magnetization (crystal axis) of each magnet particle (or each magnetic domain) in the permanent magnet is magnetized and oriented parallel to the magnetic field.

[0003] Nd-Fe-B magnets, a type of permanent magnet, are used as raw materials for both bonded magnets and sintered magnets. On the other hand, since the crystal structure of Sm-Fe-N magnets easily deteriorates at high temperatures (approximately 500°C), it is difficult to produce sintered magnets from Sm-Fe-N magnets. Therefore, Sm-Fe-N magnets are used as raw materials for bonded magnets, which can be produced by heating at low temperatures (thermosetting the thermosetting resin mixed with the magnet powder) while maintaining the crystal structure. Compared to Nd-Fe-B magnets, Sm-Fe-N magnets can be produced using inexpensive raw materials and have excellent magnetic properties.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-193189

[0007] Patent Document 2: Japanese Utility Model Application Laid-Open No. 6-79134 Summary of the Invention

[0008] Technical issues to be solved by the invention

[0009] Permanent magnets are used in various technical fields as parts that constitute motors or actuators. For example, permanent magnets are used in various industrial products such as electric vehicles, hybrid vehicles, smart phones, magnetic resonance imaging devices (MRI), digital cameras, thin TVs, hard disk drives, scanners, air conditioners, heat pumps, refrigerators, vacuum cleaners, washing machines, elevators and wind turbines. According to these various uses, the size, shape and magnetization direction (magnetization direction) required for permanent magnets are different. Therefore, in order to manufacture a variety of permanent magnets, it is expected that the magnetization direction of the permanent magnet can be easily changed according to the use, size and shape of the permanent magnet. In order to easily change the magnetization direction of the permanent magnet, it is expected that the direction and intensity of the magnetic field applied to the raw material in the mold can be easily changed and controlled. In particular, with the miniaturization of permanent magnets, it is necessary to accurately change and control the direction and intensity of the magnetic field in a narrow area (the area where the small mold containing the raw material is set). For example, the magnet powder in the raw material can be oriented along the magnetic field lines with a specified curvature. In other words, each magnetic region in the permanent magnet can be oriented along a curve with a specified curvature. The magnetic powder in the raw material can also be oriented along the magnetic lines of force while maintaining the angle between the direction of pressurization of the raw material and the magnetic lines of force at an arbitrary value. In other words, the angle between the direction of pressurization of the raw material and the orientation direction of the magnetic powder in the raw material can be adjusted to any value. The magnetic field can also be controlled so that a portion of the magnetic field with relatively low magnetic flux density is applied to the raw material in the mold.

[0010] However, in conventional permanent magnet manufacturing devices, the mold's movable range is limited, and the coil's position and orientation are fixed. Consequently, it's difficult to freely change the direction of the magnetic field applied by the coil to the raw material within the mold. In other words, it's difficult to freely change the magnetization direction of the permanent magnet using conventional permanent magnet manufacturing devices.

[0011] An object of one aspect of the present invention is to provide a permanent magnet manufacturing apparatus capable of easily changing the magnetization direction of the permanent magnet.

[0012] Means for solving technical problems

[0013] For example, one aspect of the present invention relates to a permanent magnet manufacturing apparatus described in any one of the following [1] to [5].

[0014] [1] A device for manufacturing a permanent magnet, wherein:

[0015] The manufacturing device includes a compression molding mechanism and a magnetic field generating mechanism.

[0016] The compression forming mechanism includes a pair of punches facing each other and a cylindrical die into which the pair of punches are inserted.

[0017] The magnetic field generating mechanism includes a pair of coils.

[0018] The compression molding mechanism is placed between a pair of coils.

[0019] The compression molding mechanism does not penetrate the inner sides of each of the pair of coils.

[0020] The raw material containing magnet powder is fed into the die,

[0021] A magnetic field is generated by at least one coil of a pair of coils,

[0022] A magnetic field is applied to the raw material in the die, and a pair of punches is used to compress the raw material in the die, thereby forming a compact from the raw material.

[0023] The direction of the magnetic field applied to the material in the die changes by at least one operation selected from the group consisting of movement of the entire magnetic field generating mechanism, rotation of the entire magnetic field generating mechanism, and rotation of at least one coil.

[0024] [2] A device for manufacturing a permanent magnet, wherein:

[0025] The manufacturing device includes a compression molding mechanism and a magnetic field generating mechanism.

[0026] The compression forming mechanism includes a pair of punches facing each other and a cylindrical die into which the pair of punches are inserted.

[0027] The magnetic field generating mechanism includes a pair of coils.

[0028] At least a portion of the compression molding mechanism is disposed inside each of the pair of coils.

[0029] The raw material containing magnet powder is fed into the die,

[0030] A magnetic field is generated by at least one coil of a pair of coils,

[0031] A magnetic field is applied to the raw material in the die, and the raw material in the die is compressed by a pair of punches, thereby forming a formed body from the raw material.

[0032] The direction of the magnetic field applied to the material in the die changes by at least one operation selected from the group consisting of movement of the entire magnetic field generating mechanism, rotation of the entire magnetic field generating mechanism, and rotation of at least one coil.

[0033] [3] The permanent magnet manufacturing device according to [1] or [2], wherein:

[0034] The pressing direction is defined as the direction in which a pair of punches face each other.

[0035] The entire magnetic field generating mechanism moves in at least one of a direction parallel to the pressurizing direction and a direction perpendicular to the pressurizing direction.

[0036] [4] The permanent magnet manufacturing device according to any one of [1] to [3], wherein

[0037] The pressing direction is defined as the direction in which a pair of punches face each other.

[0038] The distance from the rotation axis of the entire magnetic field generating mechanism to one coil is equal to the distance from the rotation axis to the other coil.

[0039] The rotation axis is perpendicular to the pressurizing direction.

[0040] The entire magnetic field generating mechanism rotates relative to the rotation axis.

[0041] [5] The permanent magnet manufacturing device according to any one of [1] to [4], wherein

[0042] The pressing direction is defined as the direction in which a pair of punches face each other.

[0043] At least one coil is rotated so that an angle between a central axis of the coil and the pressing direction changes.

[0044] Effects of the Invention

[0045] According to one aspect of the present invention, there is provided a permanent magnet manufacturing apparatus capable of easily changing the magnetization direction of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a schematic cross-sectional view of a manufacturing apparatus according to a first embodiment of the present invention. Figure 1 The cross section shown is parallel to the direction of pressing and passes through the pair of punches, the die and the pair of coils.

[0047] Figure 2 yes Figure 1 Schematic side view of the manufacturing apparatus shown.

[0048] Figure 3 yes Figure 1 The schematic top view of the manufacturing device shown in FIG. 1 shows the parts of the compression molding mechanism other than the die. Figure 3 is omitted.

[0049] Figure 4 Shown in Figure 1The overall movement state of the magnetic field generating mechanism in the manufacturing device is shown.

[0050] Figure 5 Shown in Figure 1 The entire magnetic field generating mechanism in the manufacturing apparatus shown is rotated.

[0051] Figure 6 Shown in Figure 1 The manufacturing apparatus shown is in a state where a pair of coils are rotating independently.

[0052] Figure 7 Show Figure 1 An example of a magnetic field applied to a workpiece by a pair of coils included in the manufacturing apparatus shown.

[0053] Figure 8 Show Figure 1 An example of a magnetic field applied to a workpiece by a pair of coils included in the manufacturing apparatus shown.

[0054] Figure 9 Show Figure 1 An example of a magnetic field applied to a workpiece by a pair of coils included in the manufacturing apparatus shown.

[0055] Figure 10 It shows Figure 1 This is an example of a magnetic field applied to a material by one coil included in the manufacturing apparatus shown.

[0056] Figure 11 Show Figure 1 An example of a magnetic field applied to a workpiece by a pair of coils included in the manufacturing apparatus shown.

[0057] Figure 12 is a schematic cross-sectional view of a manufacturing apparatus according to a second embodiment of the present invention. Figure 12 The cross section shown is parallel to the direction of pressing and passes through the pair of punches, the die and the pair of coils.

[0058] Figure 13 yes Figure 12 Schematic side view of the manufacturing apparatus shown.

[0059] Figure 14 yes Figure 12 The schematic top view of the manufacturing device shown in FIG. 1 shows the parts of the compression molding mechanism other than the die. Figure 14 is omitted.

[0060] Figure 15 Show Figure 12 An example of a magnetic field applied to a workpiece by a pair of coils included in the manufacturing apparatus shown.

[0061] Figure 16 Show Figure 12 An example of a magnetic field applied to a workpiece by a pair of coils included in the manufacturing apparatus shown. DETAILED DESCRIPTION

[0062] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used for the same components. The present invention is not limited to the following embodiments. Figures 1 to 16 The X, Y and Z axes shown in FIG. 1 are three mutually orthogonal coordinate axes. The directions of the X, Y and Z axes are the same as those in FIG. Figures 1 to 16 The "permanent magnet" described below refers to at least one anisotropic magnet among bonded magnets and sintered magnets.

[0063] (First embodiment)

[0064] Figures 1 to 11 A permanent magnet manufacturing apparatus 100 according to a first embodiment of the present invention is shown. Figure 1 A cross section of the manufacturing apparatus 100 is shown. Figure 1 The cross section shown is parallel to the front face of the manufacturing apparatus 100 . Figure 2 Show Figure 1 The manufacturing apparatus 100 is shown from the side. Figure 3 Show Figure 1 The upper surface of the manufacturing apparatus 100 is shown. Figures 4-11 The front side of the manufacturing device 100 is shown separately. Figures 4-11 (Each front view) shows a cross section of a raw material rm1 containing magnet powder and a cross section of a cylindrical die d1.

[0065] [Overview of Manufacturing Apparatus 100]

[0066] The permanent magnet manufacturing apparatus 100 includes a compression molding mechanism P10 and a magnetic field generating mechanism M10.

[0067] The compression forming mechanism P10 includes: a pair of punches (a first punch p1 and a second punch p2) facing each other; and a cylindrical die d1 into which the pair of punches are inserted. A first opening (first opening) is formed on the end surface of the die d1 opposite the first punch p1, and the first punch p1 is inserted into the first opening. A second opening (second opening) is formed on the end surface of the die d1 opposite the second punch p2, and the second punch p2 is inserted into the second opening. The second punch p2 inserted into the die d1 and the die d1 can form a cavity (concave). The first punch p1 can function as a core (convex).

[0068] The compression molding mechanism P10 also includes a first pressing mechanism p11 and a second pressing mechanism p21. For example, the first pressing mechanism p11 and the second pressing mechanism p21 can each be a hydraulic device. The first punch p1 is connected to the first pressing mechanism p11 and is freely driven by the first pressing mechanism p11. The second punch p2 is connected to the second pressing mechanism p21 and is freely driven by the second pressing mechanism p21. The die d1, the first pressing mechanism p11, and the second pressing mechanism p21 can be fixed in the manufacturing apparatus 100.

[0069] Raw material rm1 containing magnet powder is supplied to die d1. Raw material rm1 in die d1 is sandwiched between first punch p1 and second punch p2 and pressurized by the first punch p1 and second punch p2. Magnet powder can also be referred to as a plurality of magnet particles formed of permanent magnets.

[0070] The sizes and shapes of the first punch p1, the second punch p2, and the die d1 are not limited. For example, the sizes and shapes of the first punch p1, the second punch p2, and the die d1 can be changed according to the desired size and shape of the formed body (or permanent magnet). The compositions of the first punch p1, the second punch p2, and the die d1 are not limited. For example, the first punch p1, the second punch p2, and the die d1 can be made of metals that have sufficient mechanical strength to function as molds.

[0071] The pressing direction Dp (compression direction) is defined as the direction in which the pair of punches (first punch p1 and second punch p2) face each other. The pressing direction Dp (compression direction) can also be referred to as the direction in which the end faces of the pair of punches face each other or the direction perpendicular to the end faces of the pair of punches.

[0072] The magnetic field generating mechanism M10 includes a pair of coils (a first coil c1 and a second coil c2). The compression forming mechanism P10 is disposed between the pair of coils (the first coil c1 and the second coil c2). The compression forming mechanism P10 does not penetrate the inside of the pair of coils (the first coil c1 and the second coil c2).

[0073] Manufacturing apparatus 100 also includes an electric power supply mechanism. The first coil c1 and the second coil c2 are electrically connected to the power supply mechanism. The power supply mechanism freely controls the direction and absolute value of the first current Ic1 generated in the first coil c1 and the direction and absolute value of the second current Ic2 generated in the second coil c2. The power supply mechanism is omitted in the figures.

[0074] As long as the first coil c1 and the second coil c2 are conductors, the composition of the first coil c1 and the second coil c2 is not limited. The first coil c1 and the second coil c2 can be air core coils. An iron core (soft iron) can also be provided inside the first coil c1 and the second coil c2. The inner diameter and the number of turns (number of turns) of the first coil c1 and the second coil c2 are not limited. The inner diameters of the first coil c1 and the second coil c2 can be the same as each other. The inner diameters of the first coil c1 and the second coil c2 can also be different from each other. The number of turns of the first coil c1 and the second coil c2 can be the same as each other. The number of turns of the first coil c1 and the second coil c2 can also be different from each other.

[0075] In addition to a pair of coils (a first coil c1 and a second coil c2), the magnetic field generating mechanism M10 also includes a first rotating mechanism Ac1, a second rotating mechanism Ac2, a connecting member M5, and a third rotating mechanism AM10. The first coil c1 is disposed near one end of the connecting member M5 via the first rotating mechanism Ac1. The second coil c2 is disposed near the other end of the connecting member M5 via the second rotating mechanism Ac2. The manufacturing apparatus 100 also includes a moving mechanism. The connecting member M5 is connected to the moving mechanism via the third rotating mechanism AM10. The moving mechanism is omitted in the figures.

[0076] [Overall Movement of the Magnetic Field Generating Mechanism M10]

[0077] By means of the above-mentioned moving mechanism connected with the connecting part M5, the entire magnetic field generating mechanism M10 can move freely in at least one of a direction parallel to the pressurizing direction Dp and a direction perpendicular to the pressurizing direction Dp. In other words, the position of the magnetic field generating mechanism M10 is adjusted and fixed at a desired position by the moving mechanism. By means of the moving mechanism, the entire magnetic field generating mechanism M10 can move freely in two directions, a direction parallel to the pressurizing direction Dp and a direction perpendicular to the pressurizing direction Dp. However, the range of movement of the entire magnetic field generating mechanism M10 is limited to a range in which the magnetic field generating mechanism M10 does not physically interfere with the compression molding mechanism P10. The direction parallel to the pressurizing direction Dp can also be referred to as the Z-axis direction. The direction perpendicular to the pressurizing direction Dp can also be referred to as the direction parallel to the XY plane.

[0078] Figure 1 The arrangement of each of the first coil c1 and the second coil c2 before the entire magnetic field generating mechanism M10 moves is shown. Figure 4 An example of the arrangement of each of the first coil c1 and the second coil c2 after the entire magnetic field generating mechanism M10 has moved in both directions parallel to the pressurizing direction Dp and perpendicular to the pressurizing direction Dp is shown.

[0079] The specific structure of the moving mechanism is not limited as long as it has the function of moving the entire magnetic field generating mechanism M10 in at least one direction parallel to the pressurization direction Dp or perpendicular to the pressurization direction Dp. For example, the moving mechanism may include a first actuator (linear actuator) that moves the magnetic field generating mechanism M10 (connecting component M5) in a direction parallel to the pressurization direction Dp. The moving mechanism may include a second actuator (linear actuator) that moves the magnetic field generating mechanism M10 (connecting component M5) in a direction perpendicular to the pressurization direction Dp. The moving mechanism may be a multi-axis actuator that moves the magnetic field generating mechanism M10 in both directions parallel to the pressurization direction Dp and perpendicular to the pressurization direction Dp. For example, the multi-axis actuator may include a first actuator and a second actuator. For example, the magnetic field generating mechanism M10 (connecting component M5) may be directly driven by the first actuator, while the magnetic field generating mechanism M10 (connecting component M5) and the entire first actuator may be driven by the second actuator. The magnetic field generating mechanism M10 (connecting member M5) may be directly driven by the second actuator, and the magnetic field generating mechanism M10 (connecting member M5) and the second actuator may be driven as a whole by the first actuator. For example, each of the above actuators may be an electric actuator or a hydraulic actuator.

[0080] [Overall Rotation of the Magnetic Field Generating Mechanism M10]

[0081] The magnetic field generating mechanism M10 as a whole can rotate freely relative to the third rotation axis LM10 by the third rotating mechanism AM10 connected to the connecting member M5. After the magnetic field generating mechanism M10 rotates, the direction (inclination) of the magnetic field generating mechanism M10 as a whole is fixed. The third rotating mechanism AM10 and the third rotation axis LM10 are as follows: Figure 2 and Figure 3 As shown. For example, the third rotation mechanism AM10 may include a rotating shaft connected to the magnetic field generating mechanism M10 (connecting member M5), a bearing connected to the rotating shaft, and a motor that drives the rotating shaft. The overall rotation axis of the magnetic field generating mechanism M10 (third rotation axis LM10) is perpendicular to the pressurizing direction Dp. The overall rotation range of the magnetic field generating mechanism M10 is limited to an area where the magnetic field generating mechanism M10 does not physically interfere with the compression molding mechanism P10.

[0082] The distance from the overall rotation axis (third rotation axis LM10) of the magnetic field generating mechanism M10 to one coil (first coil c1) is equal to the distance from the third rotation axis LM10 to the other coil (second coil c2). For example, the distance from the overall rotation axis (third rotation axis LM10) of the magnetic field generating mechanism M10 to the first rotation axis Lc1 of the first coil c1 can be equal to the distance from the third rotation axis LM10 to the second rotation axis Lc2 of the second coil c2. For example, the distance from the overall rotation axis (third rotation axis LM10) of the magnetic field generating mechanism M10 to the center of gravity of the first coil c1 can be equal to the distance from the third rotation axis LM10 to the center of gravity of the second coil c2.

[0083] Figure 1 The arrangement of each of the first coil c1 and the second coil c2 before the entire magnetic field generating mechanism M10 rotates is shown. Figure 5 An example of the arrangement of each of the first coil c1 and the second coil c2 after the entire rotation of the magnetic field generating mechanism M10 is shown.

[0084] [Rotation of the coil]

[0085] At least one coil rotates so that the angle between the central axis of the coil and the pressure direction Dp changes. That is, by rotating the at least one coil, the angle between the central axis of the coil and the pressure direction Dp is adjusted to a desired value. Only one of the pair of coils (first coil c1 and second coil c2) can rotate. The pair of coils (first coil c1 and second coil c2) can rotate independently.

[0086] For example, through the first rotating mechanism Ac1, the first coil c1 rotates freely relative to the first rotation axis Lc1. Through the rotation of the first coil c1, the angle θ between the center axis of the first coil c1 (first center axis Cc1) and the pressurizing direction Dp changes freely. After the rotation of the first coil c1, the direction (tilt) of the first coil c1 is fixed. The range of rotation of the first coil c1 is limited to the range where the first coil c1 does not physically interfere with the compression molding mechanism P10. The rotation axis of the first coil c1 (first rotation axis Lc1) is perpendicular to the pressurizing direction Dp and parallel to the overall rotation axis (third rotation axis LM10) of the magnetic field generating mechanism M10. The first rotating mechanism Ac1 may include a rotating shaft connected to the first coil c1, a bearing connecting the rotating shaft, and a motor driving the rotating shaft.

[0087] For example, through the second rotating mechanism Ac2, the second coil c2 rotates freely relative to the second rotation axis Lc2. Through the rotation of the second coil c2, the angle between the center axis of the second coil c2 (second center axis Cc2) and the pressurization direction Dp changes freely. After the rotation of the second coil c2, the direction (inclination) of the second coil c2 is fixed. The range of rotation of the second coil c2 is limited to the range where the second coil c2 does not physically interfere with the compression molding mechanism P10. The rotation axis of the second coil c2 (second rotation axis Lc2) is perpendicular to the pressurization direction Dp and parallel to the overall rotation axis (third rotation axis LM10) of the magnetic field generating mechanism M10. The second rotating mechanism Ac2 may include a rotating shaft connected to the second coil c2, a bearing connecting the rotating shaft, and a motor driving the rotating shaft.

[0088] Figure 1 The directions (inclinations) of the first coil c1 and the second coil c2 before they are rotated are shown. Figure 6 An example of the directions (inclinations) of the first coil c1 and the second coil c2 after the first coil c1 and the second coil c2 have each rotated is shown.

[0089] [Method for Manufacturing Permanent Magnet Using Manufacturing Apparatus 100]

[0090] A magnetic field H is generated by at least one of a pair of coils (first coil c1 and second coil c2). This magnetic field H is applied to the raw material rm1 within the die d1, and the raw material rm1 within the die d1 is compressed by a pair of punches (first punch p1 and second punch p2). As a result, a compact is formed from the raw material rm1, and the individual magnetic particles (magnetic domains within each magnetic particle) within the compact are magnetized and oriented along the magnetic field H.

[0091] The magnetic field H can be synthesized by the magnetic fields generated by the first coil c1 and the second coil c2, and the synthesized magnetic field H can be applied to the raw material rm1 in the die d1. Alternatively, the magnetic field H generated by only one of the first coil c1 and the second coil c2 can be applied to the raw material rm1 in the die d1. The magnetic field H can be a static magnetic field (a magnetic field in which the distribution of magnetic flux does not change over time) or a pulsed magnetic field.

[0092] The direction of the magnetic field H applied to the raw material rm1 within the die d1 can be freely varied by at least one operation selected from the group consisting of: movement of the entire magnetic field generating mechanism M10; rotation of the entire magnetic field generating mechanism M10; and rotation of at least one of the first coil c1 and the second coil c2. Specifically, the direction of the magnetic field H applied to the raw material rm1 within the die d1 can be freely adjusted by any of the above operations before the application of the magnetic field H to the raw material rm1 within the die d1 begins. Therefore, the magnetization direction and orientation of each magnetic grain (magnetic domain within each magnetic grain) within the formed body can be freely controlled. The magnetization direction and orientation of each magnetic grain (magnetic domain within each magnetic grain) within the formed body are maintained in the finished permanent magnet. Therefore, by controlling the magnetization direction and orientation of each magnetic grain (magnetic domain within each magnetic grain) within the formed body, the magnetization direction of the permanent magnet can be easily varied and adjusted. In other words, according to the manufacturing apparatus 100, the magnetization direction of the permanent magnet can be easily varied and adjusted according to the application, size, and shape of the permanent magnet.

[0093] Below, reference Figures 7-11 , a specific example of the magnetic field H applied to the raw material rm1 in the die d1 is described.

[0094] exist Figure 7 In the manufacturing device 100 shown, the raw material rm1 in the die d1 is arranged between the first coil c1 and the second coil c2. The first coil c1 and the second coil c2 are opposite to each other. The central axes of the first coil c1 and the second coil c2 are consistent with each other, perpendicular to the pressing direction Dp, and pass through the center of the raw material rm1. The direction of the first current Ic1 in the first coil c1 is the same as the direction of the second current Ic2 in the second coil c2. Figure 7 In the manufacturing apparatus 100 shown, the magnetic flux density of the magnetic field H is highest between the first coil c1 and the second coil c2. The linear magnetic field H formed between the first coil c1 and the second coil c2 is applied to the raw material rm1. The magnetic field H applied to the raw material rm1 is perpendicular to the pressurization direction Dp. Therefore, each magnetic particle (the magnetic domain within each magnetic particle) in the formed body is also magnetized and oriented in a direction perpendicular to the pressurization direction Dp.

[0095] exist Figure 8In the manufacturing device 100 shown, the magnetic field generating mechanism M10 is maintained in an overall rotating state. The raw material rm1 in the die d1 is arranged between the first coil c1 and the second coil c2. The first coil c1 and the second coil c2 are opposite to each other. The central axes of the first coil c1 and the second coil c2 are consistent with each other, inclined relative to the pressurizing direction Dp, and pass through the center of the raw material rm1. The direction of the first current Ic1 in the first coil c1 is the same as the direction of the second current Ic2 in the second coil c2. Figure 8 In the manufacturing apparatus 100 shown, the magnetic flux density of the magnetic field H is highest between the first coil c1 and the second coil c2. A linear magnetic field H formed between the first coil c1 and the second coil c2 is applied to the raw material rm1. The magnetic field H applied to the raw material rm1 is inclined relative to the pressurization direction Dp. Consequently, the individual magnetic particles (magnetic domains within each magnetic particle) in the formed body are magnetized and oriented in a direction inclined relative to the pressurization direction Dp.

[0096] exist Figure 9 In the manufacturing apparatus 100 shown, the entire magnetic field generating mechanism M10 moves in a direction parallel to the pressurizing direction Dp (downward), while maintaining the first coil c1 and second coil c2 in a rotating state. The first coil c1 and second coil c2 are positioned below the raw material rm1 within the die d1. The central axes of each coil c1 and second coil c2 are parallel to the pressurizing direction Dp. That is, the angle between the central axes of each coil c1 and second coil c2 and the pressurizing direction Dp is zero degrees. The direction of the first current Ic1 flowing in the first coil c1 is opposite to the direction of the second current Ic2 flowing in the second coil c2. A curved magnetic flux extends from the upper end of the first coil c1 toward the upper end of the second coil c2. The density of this curved magnetic flux is relatively low in the area where the raw material rm1 is positioned. Because the curved magnetic field H (magnetic flux) is applied to the raw material rm1, the magnetic particles (magnetic domains within each magnetic particle) in the formed body are magnetized and oriented along the same curve as the magnetic field H (magnetic flux).

[0097] exist Figure 10In the manufacturing apparatus 100 shown, the entire magnetic field generating mechanism M10 moves in a direction parallel to the pressurizing direction Dp (downward) and in a direction perpendicular to the pressurizing direction Dp (rightward), while maintaining its overall rotational state. A first coil c1 and a second coil c2 are positioned below the material rm1 within the die d1. A first current Ic1 is generated in the first coil c1, but no second current Ic2 is generated in the second coil c2. Therefore, the magnetic field H is generated only by the first coil c1. A magnetic field H with a curved magnetic flux and relatively low magnetic flux density is applied to the material rm1, located outside the first coil c1. Because the curved magnetic field H (magnetic flux) is applied to the material rm1, the magnetic particles (magnetic domains within each magnetic particle) in the formed body are magnetized and oriented along the same curve as the magnetic field H (magnetic flux). Because the magnetic field H applied to the material rm1 is tilted relative to the pressurizing direction Dp, the magnetic particles (magnetic domains within each magnetic particle) in the formed body are also magnetized and oriented in a direction tilted relative to the pressurizing direction Dp.

[0098] exist Figure 11 In the manufacturing apparatus 100 shown, the entire magnetic field generating mechanism M10 rotates, maintaining the first coil c1 and second coil c2 in a state of independent rotation. The first coil c1 is positioned to the left of the die d1, and the second coil c2 is positioned below the die d1. The central axis of the first coil c1 is perpendicular to the pressurizing direction Dp. That is, the angle between the central axis of the first coil c1 and the pressurizing direction Dp is 90 degrees. The central axis of the second coil c2 is parallel to the pressurizing direction Dp. That is, the angle between the central axis of the second coil c2 and the pressurizing direction Dp is zero degrees. In the magnetic field H generated by the first coil c1 and the second coil c2, a curved magnetic flux extends from the upper end of the second coil c2 toward the right end of the first coil c1. Because the curved magnetic field H (magnetic flux) is applied to the raw material rm1, the magnetic particles (magnetic domains within each magnetic particle) in the formed body are magnetized and oriented along the same curve as the magnetic field H (magnetic flux). The magnetic field H applied to the raw material rm1 is inclined relative to the pressing direction Dp, so each magnet particle in the compact (the magnetic domain in each magnet particle) is also magnetized and oriented in a direction inclined relative to the pressing direction Dp.

[0099] The direction of the magnetic field H applied to the raw material rm1 in the die d1 is not limited to Figures 7-11The directions of the magnetic fields H are shown. By changing the placement and orientation of the first coil c1 and the second coil c2 through the above operations, the direction and intensity of the magnetic field H applied to the material rm1 within the die d1 can be freely varied and adjusted. The direction and absolute value of the first current Ic1 flowing through the first coil c1 and the direction and absolute value of the second current Ic2 flowing through the second coil c2 can also be freely varied and adjusted. The direction and intensity of the magnetic field H (the direction and density of the magnetic flux) can be easily calculated through simulation using commercially available software.

[0100] The magnet powder contained in the raw material rm1 may be, for example, a Nd-Fe-B system magnet (Nd2Fe 14 B alloys), samarium-iron-nitrogen magnets (Sm2Fe 17 N3 alloys), samarium cobalt magnets (Sm2Co 17 Alloys such as ferrite), cerium-based magnets (alloys such as PrCo5), or ferrite magnets. For example, Nd-Fe-B-based magnets are used as raw materials for both bonded magnets and sintered magnets. On the other hand, since the crystal structure of Sm-Fe-N-based magnets easily deteriorates at high temperatures (approximately 500°C), it is difficult to produce sintered magnets from Sm-Fe-N-based magnets. Therefore, Sm-Fe-N-based magnets are used as raw materials for bonded magnets that can be produced by heating at low temperatures (thermal curing of the thermosetting resin mixed with the magnet powder) while maintaining the crystal structure.

[0101] As a permanent magnet, in the case of manufacturing a bonded magnet, the raw material RM1 may contain, in addition to the magnet powder, a thermosetting resin, a curing agent, a curing accelerator (curing catalyst), a silane coupling agent, a wax (lubricant), a flame retardant, and an organic solvent. In addition to the thermosetting resin, the raw material RM1 for bonded magnets may also contain a thermoplastic resin. As a permanent magnet, in the case of manufacturing a sintered magnet, the raw material RM1 may contain, in addition to the magnet powder, a wax (lubricant) and other components. The raw material RM1 is pre-mixed roughly uniformly.

[0102] In the method for manufacturing a bonded magnet, after a molded body is formed by the above method, a magnetic field (demagnetic field) in a direction opposite to the magnetic field H is applied to the molded body, thereby demagnetizing the molded body. Even in the demagnetized molded body, the easy magnetization axis of each magnetic particle in the molded body is maintained in a state oriented in the same direction as the magnetic field H. The molded body can be demagnetized using the above-mentioned manufacturing device 100. That is, the molded body can be demagnetized by applying a magnetic field (demagnetic field) in a direction opposite to the magnetic field H to the molded body clamped by the first punch p1 and the second punch p2 in the die d1. After the molded body is removed from the die d1, the molded body can be demagnetized using a device different from the above-mentioned manufacturing device 100. In the method for manufacturing a bonded magnet, a cured product of the molded body can be formed by heating the demagnetized molded body. That is, a cured product of the molded body can be formed by thermal curing of the thermosetting resin in the molded body. In the bonded magnet manufacturing method, a magnetic field directed in the same direction as the magnetic field H is applied to the solidified product of the molded body, thereby magnetizing the solidified product. This magnetization of the solidified product yields a permanent magnet (an anisotropic magnet magnetized in a specific direction). The size and shape of the permanent magnet can be adjusted by cutting the permanent magnet.

[0103] In the method for manufacturing a sintered magnet, the formed body formed by the above method is sintered to form a sintered body. The sintered body can be used as a permanent magnet (anisotropic magnet magnetized in a specific direction). Before the formed body is sintered, it can be degreased by heating it at a temperature lower than the sintering temperature of the formed body. The sintered body is magnetized by applying a magnetic field in the same direction as the above-mentioned magnetic field H to the sintered body. The magnetized sintered body can be used as a permanent magnet. The size and shape of the permanent magnet can be adjusted by cutting the permanent magnet.

[0104] (Second embodiment)

[0105] Figures 12-16 A permanent magnet manufacturing apparatus 200 according to a second embodiment of the present invention is shown. Figure 12 A cross section of the manufacturing apparatus 200 is shown. Figure 12 The cross section shown is parallel to the front face of the manufacturing apparatus 200 . Figure 13 Show Figure 12 A side view of the manufacturing apparatus 200 is shown. Figure 14 Show Figure 12 The upper surface of the manufacturing apparatus 200 is shown. Figure 15 and Figure 16The front side of the manufacturing device 200 is shown separately. Figure 15 and Figure 16 (Each front view) shows a cross section of a raw material rm1 containing magnet powder and a cross section of a cylindrical die d1.

[0106] Hereinafter, the differences between the second embodiment and the first embodiment will be mainly described.

[0107] In the permanent magnet manufacturing apparatus 200, at least a portion of the compression molding mechanism P10 is disposed inside each of a pair of coils (the first coil c1 and the second coil c2). In other words, at least a portion of the compression molding mechanism P10 passes through each of the pair of coils. For example, Figure 12 As shown, the first punch p1 penetrates the inside of the first coil c1, and the second punch p2 penetrates the inside of the second coil c2. In the manufacturing apparatus 200, the entire compression molding mechanism P10 can be placed inside each of the pair of coils (the first coil c1 and the second coil c2).

[0108] The range of overall movement of the magnetic field generating mechanism M10 is limited to a range in which the compression molding mechanism P10 disposed inside each of the pair of coils does not physically interfere with the magnetic field generating mechanism M10 .

[0109] The range of the overall rotation of the magnetic field generating mechanism M10 is limited to a range in which the compression molding mechanism P10 disposed inside each of the pair of coils does not physically interfere with the magnetic field generating mechanism M10 .

[0110] The range in which the first coil c1 rotates is limited to a range in which the compression-molding mechanism P10 disposed inside the first coil c1 does not physically interfere with the first coil c1 .

[0111] The range in which the second coil c2 rotates is limited to a range in which the compression-molding mechanism P10 disposed inside the second coil c2 does not physically interfere with the second coil c2.

[0112] The manufacturing apparatus 200 according to the second embodiment is the same as the manufacturing apparatus 100 according to the first embodiment except for the above matters. The manufacturing method of a permanent magnet using the manufacturing apparatus 200 is the same as the manufacturing method of a permanent magnet using the manufacturing apparatus 100 except for the above matters.

[0113] In the manufacturing apparatus 200, the direction of the magnetic field H applied to the raw material rm1 within the die d1 can be freely varied by at least one operation selected from the group consisting of: movement of the entire magnetic field generating mechanism M10; rotation of the entire magnetic field generating mechanism M10; and rotation of at least one of the first coil c1 and the second coil c2. Specifically, the direction of the magnetic field H applied to the raw material rm1 within the die d1 can be freely adjusted by any of the above operations before the application of the magnetic field H to the raw material rm1 within the die d1 begins. Therefore, the magnetization direction and orientation of each magnetic grain (the magnetic domain within each magnetic grain) within the formed body can be freely controlled. The magnetization direction and orientation of each magnetic grain (the magnetic domain within each magnetic grain) within the formed body are maintained in the finished permanent magnet. Therefore, by controlling the magnetization direction and orientation of each magnetic grain (the magnetic domain within each magnetic grain) within the formed body, the magnetization direction of the permanent magnet can be easily varied and adjusted. In other words, according to the manufacturing apparatus 200 , the magnetization direction of the permanent magnet can be easily changed and adjusted according to the application, size, and shape of the permanent magnet.

[0114] For example, in Figure 15 In the manufacturing device 200 shown, the raw material rm1 in the die d1 is arranged between the first coil c1 and the second coil c2. The first coil c1 and the second coil c2 are opposite to each other. The central axes of the first coil c1 and the second coil c2 are consistent with each other, parallel to the pressurization direction Dp, and pass through the center of the raw material rm1. The direction of the first current Ic1 in the first coil c1 is the same as the direction of the second current Ic2 in the second coil c2. Figure 15 In the manufacturing apparatus 100 shown, the magnetic flux density of the magnetic field H is highest between the first coil c1 and the second coil c2. The linear magnetic field H formed between the first coil c1 and the second coil c2 is applied to the raw material rm1. The magnetic field H applied to the raw material rm1 is parallel to the pressurization direction Dp. Therefore, the individual magnetic particles (magnetic domains within each magnetic particle) in the formed body are also magnetized and oriented in a direction parallel to the pressurization direction Dp.

[0115] exist Figure 16 In the manufacturing device 200 shown, the overall rotation state of the magnetic field generating mechanism M10 is maintained. The raw material rm1 in the die d1 is arranged between the first coil c1 and the second coil c2. The first coil c1 and the second coil c2 are opposite to each other. The central axes of the first coil c1 and the second coil c2 are consistent with each other, inclined relative to the pressurizing direction Dp, and pass through the center of the raw material rm1. The direction of the first current Ic1 in the first coil c1 is the same as the direction of the second current Ic2 in the second coil c2. Figure 16In the manufacturing apparatus 200 shown, the magnetic flux density of the magnetic field H is highest between the first coil c1 and the second coil c2. A linear magnetic field H formed between the first coil c1 and the second coil c2 is applied to the raw material rm1. The magnetic field H applied to the raw material rm1 is inclined relative to the pressurization direction Dp. Consequently, the individual magnetic particles (magnetic domains within each magnetic particle) in the formed body are magnetized and oriented in a direction inclined relative to the pressurization direction Dp.

[0116] The direction of the magnetic field H applied to the raw material rm1 in the die d1 is not limited to Figure 15 and Figure 16 The directions of the magnetic fields H are shown.

[0117] The present invention is not necessarily limited to the above-described embodiment. Various modifications of the present invention can be made without departing from the spirit of the present invention, and these modifications are also included in the present invention.

[0118] For example, the manufacturing apparatus 100 and the manufacturing apparatus 200 may further include a heating mechanism (heater) for heating the raw material rm1 or the formed body in the die d1.

[0119] Industrial applicability

[0120] For example, a permanent magnet manufacturing apparatus according to one aspect of the present invention is used to manufacture bonded magnets or sintered magnets.

[0121] Explanation of symbols

[0122] 100, 200-permanent magnet manufacturing device, P10-compression molding mechanism, M10-magnetic field generating mechanism, LM10-the overall rotation axis of the magnetic field generating mechanism M10, AM10-the third rotation mechanism (the rotation mechanism of the magnetic field generating mechanism M10), p1-the first punch, p11-the first pressurizing mechanism (the pressurizing mechanism of the first punch p1), p2-the second punch, p21-the second pressurizing mechanism (the pressurizing mechanism of the second punch p2), Dp-pressurizing direction, d1-die, c1-the first coil, Cc1-the central axis of the first coil c1, Lc1-the rotation axis of the first coil c1, Ac1-the A rotating mechanism (rotating mechanism of the first coil c1), Ic1-the first current in the first coil c1 and its direction, c2-the second coil, Cc2-the central axis of the second coil c2, Lc2-the rotation axis of the second coil c2, Ac2-the second rotating mechanism (rotating mechanism of the second coil c2), Ic2-the second current in the second coil c2 and its direction, M5-connecting component, rm1-raw material containing magnet powder, H-the magnetic field applied to the raw material rm1 and its direction, θ-the angle between the central axis of the coil and the pressurizing direction Dp (the angle between the central axis Cc1 of the first coil c1 and the pressurizing direction Dp).

Claims

1. A device for manufacturing a permanent magnet, wherein: The manufacturing device includes a compression molding mechanism and a magnetic field generating mechanism. The compression forming mechanism includes a pair of punches facing each other and a cylindrical die into which the pair of punches are inserted. The magnetic field generating mechanism comprises a pair of coils, The compression molding mechanism is arranged between the pair of coils. The compression molding mechanism does not penetrate the inner sides of each of the pair of coils. A raw material containing magnet powder is supplied into the die, generating a magnetic field by at least one of the pair of coils, applying the magnetic field to the raw material in the die and compressing the raw material in the die with the pair of punches, thereby forming a formed body from the raw material, The direction of the magnetic field applied to the raw material in the die changes by at least one operation selected from the group consisting of movement of the entire magnetic field generating mechanism, rotation of the entire magnetic field generating mechanism, and rotation of at least one of the coils. The magnetic field generating mechanism further includes a first rotating mechanism, a second rotating mechanism, a connecting member, and a third rotating mechanism, wherein the first coil of the pair of coils is disposed near one end of the connecting member via the first rotating mechanism, and the second coil of the pair of coils is disposed near the other end of the connecting member via the second rotating mechanism. The manufacturing apparatus further includes a moving mechanism, and the connecting member is connected to the moving mechanism via the third rotating mechanism.

2. A permanent magnet manufacturing device, wherein: The manufacturing device includes a compression molding mechanism and a magnetic field generating mechanism. The compression forming mechanism includes a pair of punches facing each other and a cylindrical die into which the pair of punches are inserted. The magnetic field generating mechanism comprises a pair of coils, At least a portion of the compression molding mechanism is disposed inside each of the pair of coils. A raw material containing magnet powder is supplied into the die, generating a magnetic field by at least one of the pair of coils, applying the magnetic field to the raw material in the die and compressing the raw material in the die with the pair of punches, thereby forming a formed body from the raw material, The direction of the magnetic field applied to the raw material in the die changes by at least one operation selected from the group consisting of movement of the entire magnetic field generating mechanism, rotation of the entire magnetic field generating mechanism, and rotation of at least one of the coils. The magnetic field generating mechanism further includes a first rotating mechanism, a second rotating mechanism, a connecting member, and a third rotating mechanism, wherein the first coil of the pair of coils is disposed near one end of the connecting member via the first rotating mechanism, and the second coil of the pair of coils is disposed near the other end of the connecting member via the second rotating mechanism. The manufacturing apparatus further includes a moving mechanism, and the connecting member is connected to the moving mechanism via the third rotating mechanism.

3. The permanent magnet manufacturing device according to claim 1 or 2, wherein: The pressing direction is defined as the direction in which the pair of punches face each other. The entire magnetic field generating mechanism moves in at least one of a direction parallel to the pressurizing direction and a direction perpendicular to the pressurizing direction.

4. The permanent magnet manufacturing device according to claim 1 or 2, wherein: The pressing direction is defined as the direction in which the pair of punches face each other. The distance from the rotation axis of the entire magnetic field generating mechanism to one coil is equal to the distance from the rotation axis to another coil. The rotation axis is perpendicular to the pressurizing direction, The entire magnetic field generating mechanism rotates relative to the rotation axis.

5. The permanent magnet manufacturing device according to claim 1 or 2, wherein: The pressing direction is defined as the direction in which the pair of punches face each other. At least one of the coils rotates so that an angle between a central axis of the coil and the pressurizing direction changes.

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