Apparatus for manufacturing magnetic molded bodies, and method for manufacturing magnetic molded bodies

Abstract

The magnetization direction of the magnetic molded body can be easily changed. [Solution] The magnetic molded body manufacturing apparatus 1 comprises a mold 2 into which a magnetic molded body material M containing magnetic powder is supplied, a compression mechanism 3 for compressing the material M supplied to the mold 2, a first coil 4 and a second coil 5 arranged to sandwich the mold 2, and a first yoke 6 arranged between the first coil 4 and the mold 2. The first yoke 6 is movable so as to change its position relative to the first coil 4.

Description

Technical Field

[0001] The present disclosure relates to an apparatus for manufacturing a magnetic molded body and a method for manufacturing a magnetic molded body.

Background Art

[0002] Permanent magnets such as bonded magnets and sintered magnets are formed using magnetic molded bodies. In the manufacture of magnetic molded bodies, a material containing magnet powder (a large number of magnet particles) is supplied into a mold. While applying a magnetic field generated by a coil to the material in the mold, the material is compressed to form a magnetic molded body from the material. Each magnet particle (magnetic domain in each magnet particle) in the magnetic molded body is magnetized and oriented along the magnetic field (see, for example, Patent Documents 1 and 2). For example, in a general method for manufacturing a magnetic molded body, the mold is arranged so that a portion where the density of magnetic field lines (magnetic flux) is high in the magnetic field passes through the material in the mold, and a magnetic field parallel or perpendicular to the pressurization direction (compression direction) of the material is applied to the material in the mold. As a result, the easy magnetization axis (crystal axis) of each magnet particle (or each magnetic domain) in the magnetic molded body is magnetized and oriented parallel to the magnetic field.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Permanent magnets are used in various technological fields, for example, as components in motors or actuators. The required magnetization direction of a magnetic molded body varies depending on the application of the permanent magnet. Therefore, it is desirable to be able to easily change the magnetization direction of a magnetic molded body according to the application of the permanent magnet. To easily change the magnetization direction of a magnetic molded body, it is desirable to be able to easily control the direction and intensity of the magnetic field applied to the material in the mold.

[0005] However, in typical magnetic molding equipment, the range of motion of the mold is limited, and the position and orientation of the coil are fixed. Therefore, it is difficult to freely change the direction and intensity of the magnetic field applied to the material inside the mold in magnetic molding equipment.

[0006] This disclosure aims to provide a manufacturing apparatus for a magnetic molded body that can easily change the magnetization direction of the magnetic molded body, and a method for manufacturing a magnetic molded body. [Means for solving the problem]

[0007] One aspect of the present disclosure is [1] "a magnetic mold manufacturing apparatus comprising: a mold into which a material for a magnetic mold containing magnetic powder is supplied; a compression mechanism for compressing the material supplied to the mold; a first coil and a second coil arranged to sandwich the mold; and a first yoke arranged between the first coil and the mold, wherein the first yoke is movable such that the position of the first yoke relative to the first coil changes."

[0008] In the above-described magnetic molded body manufacturing apparatus, a first yoke is positioned between the first coil and the mold, and the first yoke is movable so as to change its position relative to the first coil. When the first yoke is placed in a magnetic field, it has the function of collecting the magnetic field lines (magnetic flux) of the magnetic field. Therefore, by moving the first yoke and changing its position, the direction and strength of the magnetic field applied to the material in the mold can be easily controlled. Thus, the magnetization direction of the magnetic molded body can be easily changed by changing the position of the first yoke, without changing the position and orientation of the mold, the first coil, and the second coil, for example. Therefore, according to the above-described magnetic molded body manufacturing apparatus, the magnetization direction of the magnetic molded body can be easily changed.

[0009] The above-described apparatus for manufacturing a magnetic molded body may also be [2] "the apparatus for manufacturing a magnetic molded body according to [1] above, wherein the respective coil axes of the first coil and the second coil are aligned in the direction in which the first coil and the second coil are aligned, and the first yoke is movable in a direction intersecting the direction in which the first coil and the second coil are aligned." Compared to the case where the first yoke is moved in the direction in which the first coil and the second coil are aligned, the direction of the magnetic field changes significantly when the first yoke is moved in a direction intersecting the direction in which the first coil and the second coil are aligned. Therefore, the above-described apparatus for manufacturing a magnetic molded body can change the magnetization direction of the magnetic molded body more efficiently.

[0010] The above-described apparatus for manufacturing a magnetic molded body may also be [3] "the apparatus for manufacturing a magnetic molded body according to [1] or [2] above, further comprising a second yoke disposed between the second coil and the mold, wherein the second yoke is movable such that the position of the second yoke relative to the second coil changes." In this case, the ways in which the direction and intensity of the magnetic field applied to the material in the mold can be changed become more diverse, and a more appropriate magnetization direction for the magnetic molded body can be achieved according to the application of the permanent magnet, etc.

[0011] The above-described apparatus for manufacturing a magnetic molded body may also be [4] "the apparatus for manufacturing a magnetic molded body described in [3] above, wherein the coil axes of the first coil and the second coil are aligned in the direction in which the first coil and the second coil are aligned, and the second yoke is movable in a direction intersecting the direction in which the first coil and the second coil are aligned." Compared to the case where the second yoke is moved in the direction in which the first coil and the second coil are aligned, the direction of the magnetic field changes significantly when the second yoke is moved in a direction intersecting the direction in which the first coil and the second coil are aligned. Therefore, the above-described apparatus for manufacturing a magnetic molded body can change the magnetization direction of the magnetic molded body more efficiently.

[0012] The above-described apparatus for manufacturing a magnetic molded body may also be [5] "the apparatus for manufacturing a magnetic molded body according to [3] or [4] above, wherein the compression mechanism has a first punch and a second punch facing each other, and each of the first yoke and the second yoke is movable in the opposing direction of the first punch and the second punch." In this case, the magnetization direction of the magnetic molded body can be changed more efficiently.

[0013] The above-described apparatus for manufacturing a magnetic molded body may also be [6] "the apparatus for manufacturing a magnetic molded body according to [5] above, wherein the first yoke is movable so as to approach the first punch in the opposing direction, and the second yoke is movable so as to approach the second punch in the opposing direction." In this case, for example, even if the first coil and the second coil are arranged side by side in a direction perpendicular to the opposing direction of the first punch and the second punch, the direction of the magnetic field can be tilted with respect to that perpendicular direction.

[0014] The above-described apparatus for manufacturing a magnetic molded body may also be [7] "the apparatus for manufacturing a magnetic molded body according to [5] or [6] above, wherein each of the first yoke and the second yoke is movable so as to approach the second punch in the opposing direction." In this case, the strength of the magnetic field in the region of the space within the mold (material of the magnetic molded body) located near the second punch can be increased. That is, the strength of the magnetic field applied to the material in the mold can be easily controlled.

[0015] One aspect of the present disclosure is [8] "A method for manufacturing a magnetic molded body using a magnetic molded body manufacturing apparatus described in any one of [1] to [7] above, comprising the steps of: supplying the material to the mold; moving the first yoke so that the position of the first yoke relative to the first coil changes; and applying a magnetic field to the material supplied to the mold using the first coil and the second coil, wherein the step of moving the first yoke is performed before or together with the step of applying the magnetic field." In this case, for the reasons described above, the direction and intensity of the magnetic field applied to the material in the mold can be easily controlled in the step of applying the magnetic field. This makes it possible to easily change the magnetization direction of the magnetic molded body. Furthermore, when the step of moving the first yoke is performed together with the step of applying the magnetic field, for example, by continuously moving the first yoke while applying the magnetic field, the magnetic powder in the material of the magnetic molded body can be dissolved (dispersed), or the direction of the applied magnetic field can be dynamically changed. [Effects of the Invention]

[0016] According to one aspect of this disclosure, the magnetization direction of a magnetic molded body can be easily changed. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic diagram showing a manufacturing apparatus for a magnetic molded body according to one embodiment. [Figure 2]FIG. 2 is a partially enlarged view of the manufacturing apparatus for the magnetic molded body shown in FIG. 1. [Figure 3] FIG. 3 is a diagram showing an example of the movement mode of the first yoke and the second yoke. [Figure 4] FIG. 4 is a diagram showing another example of the movement mode of the first yoke and the second yoke.

MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, exemplary embodiments will be described with reference to the drawings. In each figure, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0019] [Manufacturing Apparatus for Magnetic Molded Body] Referring to FIGS. 1 and 2, the configuration of the manufacturing apparatus 1 for the magnetic molded body according to the present embodiment will be described. FIG. 1 is a diagram schematically showing the manufacturing apparatus 1. In FIG. 1, a cross section of the configuration excluding the first coil 4 and the second coil 5 described later is shown. FIG. 2 is a partially enlarged view of the manufacturing apparatus 1 shown in FIG. 1. The manufacturing apparatus 1 is an apparatus for manufacturing a magnetic molded body from a material (raw material) containing magnetic powder. The magnetic molded body is an object obtained by molding a magnetic material into a specific shape and having magnetic properties. The magnetic molded body may be used, for example, in the production of permanent magnets such as bonded magnets and sintered magnets. Permanent magnets are used in various industrial products such as electric vehicles, hybrid vehicles, smartphones, magnetic resonance imaging devices (MRI), digital cameras, thin TVs, hard disk drives, scanners, air conditioners, heat pumps, refrigerators, vacuum cleaners, washing and drying machines, elevators, and wind turbines.

[0020] As shown in FIGS. 1 and 2, the manufacturing apparatus 1 includes a mold 2, a compression mechanism 3, a first coil 4, a second coil 5, a first yoke 6, a second yoke 7, a first moving mechanism 8, and a second moving mechanism 9. The compression mechanism 3 has a first punch 31 and a second punch 32 that compress the material of the magnetic molded body supplied to the mold 2, and the first punch 31 and the second punch 32 face each other. Hereinafter, the direction in which the first punch 31 and the second punch 32 face each other is defined as the Z-axis direction, one direction intersecting the Z-axis direction is defined as the X-axis direction, and the direction intersecting the Z-axis direction and the X-axis direction is defined as the Y-axis direction. In this example, the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other.

[0021] The mold 2 is supplied with a material M of a magnetic molded body containing magnetic powder. The magnetic powder contained in the material M may be, for example, an Nd-Fe-B-based magnet (an alloy such as Nd2Fe 14 B, etc.), a samarium-iron-nitrogen-based magnet (Sm2Fe 17 N3, etc.), a samarium cobalt-based magnet (Sm2Co 17 etc.), a praseodymium-based magnet (an alloy such as PrCo5), or a ferrite magnet. For example, Nd-Fe-B-based magnets are used for materials of magnetic molded bodies that become bonded magnets and sintered magnets. On the other hand, since the crystal structure of Sm-Fe-N-based magnets is likely to deteriorate at high temperatures (about 500°C), it is difficult to manufacture sintered magnets from Sm-Fe-N-based magnets. Therefore, Sm-Fe-N-based magnets are used for materials of magnetic molded bodies that become bonded magnets that can be manufactured by heating at a low temperature at which the crystal structure is maintained (thermosetting of the thermosetting resin mixed with the magnetic powder).

[0022] When a bonded magnet is manufactured using a magnetic molded body, material M may contain, in addition to magnet powder, components such as thermosetting resin, curing agent, curing accelerator (curing catalyst), silane coupling agent, wax (lubricant), flame retardant, and organic solvent. Material M for bonded magnets may further contain thermoplastic resin in addition to thermosetting resin. When a sintered magnet is manufactured using a magnetic molded body, material M may contain, in addition to magnet powder, components such as wax (lubricant). Material M may be pre-mixed to a substantially uniform state. Material M may be in the form of powder, tablet, or paste.

[0023] The mold 2 has a cylindrical shape that extends along the Z-axis direction (having an axis aligned with the Z-axis direction). The mold 2 is made of, for example, metal. Inside the mold 2, a space S is formed into which material M is supplied. The mold 2 has an end face 21 and an end face 22 located on the opposite side of the end face 21 in the Z-axis direction. An opening is formed in the end face 21 into which the end of the first punch 31 is inserted. An opening is formed in the end face 22 into which the end of the second punch 32 is inserted. The openings formed in the end face 21 and the end face 22 are connected to the space S of the mold 2.

[0024] The compression mechanism 3 is a device for compressing the material M supplied to the space S of the mold 2. The compression mechanism 3 includes a first punch 31, a second punch 32, a first pressurizing mechanism 33, and a second pressurizing mechanism 34. The first punch 31 has a columnar shape (for example, a rectangular prism shape) extending along the Z-axis direction. The first punch 31 is made of, for example, metal. The first punch 31 has an end face 31a. In the Z-axis direction, the end face 31a faces the end face 32a of the second punch 32, which will be described later. The tip of the first punch 31 (the end where the end face 31a is located) is inserted into the space S through an opening formed in the end face 21 of the mold 2. The end of the first punch 31 opposite to the end face 31a is connected to the first pressurizing mechanism 33.

[0025] The second punch 32 has a columnar shape (for example, a rectangular prism shape) that extends along the Z-axis direction. The second punch 32 is made of, for example, metal. The second punch 32 has an end face 32a that faces the end face 31a in the Z-axis direction. The tip of the second punch 32 (the end where the end face 32a is located) is inserted into the space S through an opening formed in the end face 22 of the mold 2. The end of the second punch 32 opposite to the end face 32a is connected to the second pressurizing mechanism 34.

[0026] The first pressurizing mechanism 33 is a device that moves the first punch 31 along the Z-axis direction. The first pressurizing mechanism 33 may be, for example, a hydraulic device. The first pressurizing mechanism 33 is fixed in the manufacturing apparatus 1. The second pressurizing mechanism 34 is a device that moves the second punch 32 along the Z-axis direction. The second pressurizing mechanism 34 may be, for example, a hydraulic device. The second pressurizing mechanism 34 is fixed in the manufacturing apparatus 1. The first pressurizing mechanism 33 and the second pressurizing mechanism 34 move the first punch 31 and the second punch 32 closer to each other in the Z-axis direction. As a result, the first punch 31 and the second punch 32 compress the material M placed between the end faces 31a and 32a. At this time, the material M may be compressed by moving only the first punch 31 while the second punch 32 is fixed.

[0027] The first coil 4 and the second coil 5 are arranged so as to sandwich the mold 2 in the X-axis direction. Arrangement of the first coil 4 and the second coil 5 so as to sandwich the mold 2 means that the mold 2 is located between the first coil 4 and the second coil 5; the first coil 4 and the second coil 5 do not need to be in contact with the mold 2. In this example, the first coil 4 and the second coil 5 are spaced apart from the mold 2. The first coil 4, the mold 2, and the second coil 5 are arranged in this order in the X-axis direction.

[0028] The first coil 4 is an air-core coil having a helical shape. The first coil 4 is formed from a conductor. The first coil 4 may be formed, for example, by winding a wire in a helical shape. In this example, the coil axis direction of the first coil 4 is along the X-axis direction in which the first coil 4 and the second coil 5 are aligned. The coil axis of the first coil 4 passes through the central part of the space S (material M) in the Z-axis direction.

[0029] The second coil 5 is an air-core coil having a helical shape. The second coil 5 is formed of a conductor. The second coil 5 may be formed, for example, by winding a wire in a helical shape. In this example, the coil axis direction of the second coil 5 is along the X-axis direction in which the first coil 4 and the second coil 5 are aligned. The coil axis of the second coil 5 passes through the central part of space S (material M) in the Z-axis direction. The inner diameter and number of turns of the first coil 4 and the second coil 5 are not limited. The inner diameters of the first coil 4 and the second coil 5 may be the same or different. The number of turns of the first coil 4 and the second coil 5 may be the same or different.

[0030] The manufacturing apparatus 1 further includes a power supply device (not shown) electrically connected to the first coil 4 and the second coil 5. The power supply device supplies power to the first coil 4 and the second coil 5. The power supply device controls the direction and magnitude of the current flowing through the first coil 4 and the current flowing through the second coil 5. When current flows through the first coil 4 and the second coil 5, a magnetic field is generated in each of the first coil 4 and the second coil 5. The magnetic field generated in the first coil 4 and the magnetic field generated in the second coil 5 combine to form a magnetic field H. The combined magnetic field H is applied to the material M in the mold 2.

[0031] The first yoke 6 is positioned between the first coil 4 and the mold 2. In this example, when viewed from the direction in which the first coil 4 and the mold 2 are aligned (the X-axis direction in this example), the first yoke 6 overlaps with the first coil 4 and the mold 2. That is, when viewed from the X-axis direction, the first yoke 6 is located inside the outer edge of the first coil 4 and the outer edge of the mold 2. The first yoke 6 extends along the Z-axis direction. The first yoke 6 is positioned perpendicular to the direction of the magnetic field H generated by the first coil 4 and the second coil 5.

[0032] The statement that the first yoke 6 is positioned between the first coil 4 and the mold 2 means that, in the direction in which the first coil 4 and the mold 2 are aligned, the first coil 4, the first yoke 6, and the mold 2 are arranged in this order, and it is not necessary for part or all of the first yoke 6 to overlap with the first coil 4 and the mold 2 when viewed from the direction in which the first coil 4 and the mold 2 are aligned. For example, in the example shown in Figure 1, when viewed from the X-axis direction, the first yoke 6 may be located outside the outer edge of the first coil 4 and the outer edge of the mold 2. In the example shown in Figure 1, the first yoke 6 is not inserted inside the first coil 4, and the entire first yoke 6 is located outside the first coil 4.

[0033] The first yoke 6 is formed from a high-permeability material such as Permendur, Permalloy, or Sendust. The relative permeability of the first yoke 6 may be, for example, 5000 or more. The relative permeability is the value obtained by dividing the permeability of the material of the first yoke 6 by the permeability of vacuum. The first yoke 6 has the function of collecting the magnetic field lines (magnetic flux) of the magnetic field H generated by the first coil 4 and the second coil 5. That is, the magnetic field lines of the magnetic field H preferentially pass through the region where the first yoke 6 is located. As a result, the density of magnetic field lines in the region where the first yoke 6 is located becomes higher than in other parts. That is, the strength of the magnetic field in the region where the first yoke 6 is located becomes relatively larger within the magnetic field H.

[0034] The second yoke 7 is positioned between the second coil 5 and the mold 2. In this example, when viewed from the direction in which the second coil 5 and the mold 2 are aligned (the X-axis direction in this example), the second yoke 7 overlaps with the second coil 5 and the mold 2. That is, when viewed from the X-axis direction, the second yoke 7 is located inside the outer edge of the second coil 5 and the outer edge of the mold 2. The second yoke 7 extends along the Z-axis direction. The second yoke 7 is positioned perpendicular to the direction of the magnetic field generated by the first coil 4 and the second coil 5.

[0035] The statement that the second yoke 7 is positioned between the second coil 5 and the mold 2 means that, in the direction in which the second coil 5 and the mold 2 are aligned, the second coil 5, the second yoke 7, and the mold 2 are arranged in this order, and it is not necessary for part or all of the second yoke 7 to overlap with the second coil 5 and the mold 2 when viewed from the direction in which the second coil 5 and the mold 2 are aligned. For example, in the example shown in Figure 1, when viewed from the X-axis direction, the second yoke 7 may be located outside the outer edge of the second coil 5 and the outer edge of the mold 2. In the example shown in Figure 1, the second yoke 7 is not inserted inside the second coil 5, and the entire second yoke 7 is located outside the second coil 5.

[0036] The second yoke 7 is formed from a high-permeability material such as Permendur, Permalloy, or Sendust. The relative permeability of the second yoke 7 may be, for example, 5000 or more. The relative permeability is the value obtained by dividing the permeability of the material of the second yoke 7 by the permeability of vacuum. The material of the second yoke 7 may be the same as or different from the material of the first yoke 6. The relative permeability of the second yoke 7 may be the same as or different from the relative permeability of the first yoke 6. The second yoke 7 has the function of collecting the magnetic field lines (magnetic flux) of the magnetic field H generated by the first coil 4 and the second coil 5. That is, the magnetic field lines of the magnetic field H preferentially pass through the region where the second yoke 7 is located. As a result, the density of magnetic field lines in the region where the second yoke 7 is located becomes higher than in other parts. That is, the strength of the magnetic field in the region where the second yoke 7 is located becomes relatively larger within the magnetic field H.

[0037] In the example shown in Figure 2, the central portions of the first yoke 6 and the second yoke 7 in the Z-axis direction coincide with the central portion of space S (material M). That is, the positions of the first yoke 6 and the second yoke 7 in the Z-axis direction coincide with each other. As a result, the magnetic field lines of the magnetic field H that are collected by the first yoke 6 pass through the central portion of space S (material M) before reaching the second yoke 7. In this example, the magnetic field lines passing through space S (material M) are aligned with the X-axis direction. The density of magnetic field lines passing through the central portion of space S (material M) is higher than the density of magnetic field lines passing through both ends (near the end faces 21 and 22) in the Z-axis direction of space S (material M). That is, the magnetic field strength in the central portion of space S (material M) is greater than the magnetic field strength at both ends of space S (material M). The magnetic field lines that have passed through the second yoke 7 spread out toward the second coil 5. Hereinafter, the positions of the first yoke 6 and the second yoke 7 when their respective central portions coincide with the central portion of space S (material M) in the Z-axis direction will be referred to as the reference positions.

[0038] The first moving mechanism 8 is a device for moving the first yoke 6. The first moving mechanism 8 is connected to the first yoke 6. The first moving mechanism 8 may include, for example, an actuator (linear actuator) that moves the first yoke 6 linearly. In this example, the first moving mechanism 8 is configured to include an actuator that moves the first yoke 6 along the Z-axis. The actuator may be an electric actuator or a hydraulic actuator.

[0039] The second moving mechanism 9 is a device for moving the second yoke 7. The second moving mechanism 9 is connected to the second yoke 7. The second moving mechanism 9 may include, for example, an actuator (linear actuator) that moves the second yoke 7 linearly. In this example, the second moving mechanism 9 is configured to include an actuator that moves the second yoke 7 along the Z-axis. The actuator may be an electric actuator or a hydraulic actuator.

[0040] Next, the movement of the first yoke 6 and the second yoke 7 will be described in more detail. The first yoke 6 is movable so as to change its position relative to the first coil 4. The movement of the first yoke 6 is performed by the first movement mechanism 8 described above. In this example, the first yoke 6 is movable in a direction intersecting the direction in which the first coil 4 and the mold 2 are aligned (X-axis direction). More specifically, the first yoke 6 is movable in the Z-axis direction. That is, the first yoke 6 is movable along the opposing directions of the first punch 31 and the second punch 32. The first yoke 6 is movable in the Z-axis direction so as to approach at least one of the first punch 31 and the second punch 32. In this example, the first yoke 6 is continuously movable along the Z-axis direction.

[0041] The second yoke 7 is movable such that its position relative to the second coil 5 changes. The movement of the second yoke 7 is performed by the second movement mechanism 9 described above. In this example, the second yoke 7 is movable in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned (X-axis direction). More specifically, the second yoke 7 is movable in the Z-axis direction. That is, the second yoke 7 is movable along the opposing directions of the first punch 31 and the second punch 32. The second yoke 7 is movable in the Z-axis direction so as to approach at least one of the first punch 31 and the second punch 32. In this example, the second yoke 7 is continuously movable along the Z-axis direction.

[0042] Figure 3 shows an example of the movement of the first yoke 6 and the second yoke 7. As shown in Figure 3, the first yoke 6 and the second yoke 7 are moving from their respective positions (reference positions) shown in Figure 2. More specifically, the first yoke 6 moves in the Z-axis direction from its reference position towards the first punch 31, and the second yoke 7 moves in the Z-axis direction from its reference position towards the second punch 32. The movement of the first yoke 6 and the second yoke 7 is performed by the first movement mechanism 8 and the second movement mechanism 9. After the movement, the first yoke 6 is located closer to the first punch 31 than to the second punch 32 in the Z-axis direction. After the movement, the second yoke 7 is located closer to the second punch 32 than to the first punch 31 in the Z-axis direction. In other words, in the state after the movement, the first yoke 6 is located closer to the first punch 31 than to the second yoke 7, and the second yoke 7 is located closer to the second punch 32 than to the first yoke 6.

[0043] As described above, the first yoke 6 and the second yoke 7 have the function of concentrating magnetic field lines. Therefore, as shown in Figure 3, the magnetic field lines of the magnetic field H generated by the first coil 4 and the second coil 5 that are concentrated by the first yoke 6 pass through space S (material M) and then propagate toward the second yoke 7. At this time, the magnetic field lines passing through space S (material M) propagate at an inclination with respect to the X-axis direction. More specifically, as the magnetic field lines move from the first yoke 6 toward the second yoke 7, they move toward the second punch 32 from the first punch 31.

[0044] Figure 4 shows another example of the movement of the first yoke 6 and the second yoke 7. As shown in Figure 4, the first yoke 6 and the second yoke 7 are moved from their respective positions (reference positions) shown in Figure 2. More specifically, the first yoke 6 and the second yoke 7 are moved in the Z-axis direction from their reference position towards the second punch 32. The movement of the first yoke 6 and the second yoke 7 is performed by the first movement mechanism 8 and the second movement mechanism 9. After the movement, the first yoke 6 and the second yoke 7 are located closer to the first punch 31 than to the second punch 32 in the Z-axis direction.

[0045] Of the magnetic field lines of the magnetic field H generated by the first coil 4 and the second coil 5, those collected by the first yoke 6 pass through space S (material M) and then propagate toward the second yoke 7. In the example shown in Figure 4, the positions of the first yoke 6 and the second yoke 7 in the Z-axis direction coincide with each other. Therefore, the magnetic field lines passing through space S (material M) propagate along the X-axis direction. More specifically, the magnetic field lines mainly pass through the region of space S (material M) located near the second punch 32. In other words, the density of magnetic field lines passing through the region of space S (material M) located near the second punch 32 is higher than the density of magnetic field lines passing through the region of space S (material M) located near the first punch 31. That is, the magnetic field strength in the region of space S (material M) located near the second punch 32 is greater than the magnetic field strength in the region of space S (material M) located near the first punch 31.

[0046] [Method for manufacturing magnetic molded bodies] Next, a method for manufacturing a magnetic molded body will be described. First, the material M for the magnetic molded body is supplied to the mold 2. At this time, the tip of the second punch 32 (the end where the end face 32a is located) is inserted into the space S through an opening formed in the end face 22 of the mold 2. This creates a recess between the inner surface of the mold 2 and the end face 32a. The material M is supplied into this recess. The supply mechanism for supplying the material M to the mold 2 may be provided as part of the manufacturing apparatus 1, or it may be provided as a separate component from the manufacturing apparatus 1. The configuration of the supply mechanism is not limited. After the material M has been supplied, the tip of the first punch 31 is inserted into the space S through an opening in the end face 21 of the mold 2. This causes the material M to be contained within the space defined by the inner surface of the mold 2 and the end faces 21 and 22.

[0047] Next, the material M is compressed using the compression mechanism 3. Specifically, the first pressurizing mechanism 33 and the second pressurizing mechanism 34 move the first punch 31 and the second punch 32 closer to each other in the Z-axis direction. As a result, the first punch 31 and the second punch 32 compress the material M positioned between the end faces 31a and 32a. At this time, the material M may be compressed by moving only the first punch 31 while keeping the second punch 32 fixed. Alternatively, the material M may be compressed by moving only the second punch 32 while keeping the first punch 31 fixed. In other words, it is sufficient to have a configuration in which the first punch 31 and the second punch 32 move so that the distance between the end faces 21 and 22 becomes relatively close.

[0048] Next, the first yoke 6 and the second yoke 7 are moved. In this embodiment, the first moving mechanism 8 moves the first yoke 6 so that its position relative to the first coil 4 changes. The second moving mechanism 9 moves the second yoke 7 so that its position relative to the second coil 5 changes. As an example, as shown in Figure 3, the first moving mechanism 8 may move the first yoke 6 closer to the first punch 31 in the Z-axis direction, and the second moving mechanism 9 may move the second yoke 7 closer to the second punch 32 in the Z-axis direction. As another example, as shown in Figure 4, the first moving mechanism 8 may move the first yoke 6 closer to the second punch 32 in the Z-axis direction, and the second moving mechanism 9 may move the second yoke 7 closer to the second punch 32 in the Z-axis direction.

[0049] Next, a magnetic field H is applied to the material M using the first coil 4 and the second coil 5. The power supply device supplies current to the first coil 4 and the second coil 5, generating magnetic fields in each of them. The magnetic field H is combined from the magnetic field generated in the first coil 4 and the magnetic field generated in the second coil 5. The combined magnetic field H is applied to the material M in the mold 2. The magnetization direction of the entire magnetic molded body is approximately or perfectly parallel to the direction of the magnetic field H applied to the material M.

[0050] In this embodiment, a magnetic field H is applied to the material M in the mold 2 by the first coil 4 and the second coil 5 while the material M in the mold 2 is compressed by the first punch 31 and the second punch 32. Each magnetic particle in the material M is magnetized and rotated by the magnetic field H, and the easy magnetization axis of the magnetic domain in each magnetic particle is oriented along the magnetic field H. In other words, each magnetic particle in the material M is oriented so that its magnetization direction is approximately parallel to the magnetic field H. If each magnetic particle is a single crystal grain (single magnetic domain), the magnetization direction of each magnetic particle is the same as the direction in which the easy magnetization axis of each magnetic particle extends. Through the above process, a magnetic molded body is formed.

[0051] The application of the magnetic field H may be terminated at the same time as the molding pressure reaches its maximum value. The application of the magnetic field H may be terminated when the molding pressure begins to decrease. The application of the magnetic field H may be terminated at the same time as the compression of the material M in the mold 2 ends. The magnetic field H applied to the material M may be a static magnetic field (a continuous, constant magnetic field). The magnetic field H may be a pulsed magnetic field (a pulsed magnetic field). The start and end of the application of the magnetic field H may be controlled by the control unit of the power supply mechanism controlling the power supplied to the first coil 4 and the second coil 5.

[0052] When a magnetic molded body is used in the manufacture of bonded magnets, the magnetic molded body may be demagnetized by applying a magnetic field (reverse magnetic field) that is oriented in the opposite direction to the magnetic field H described above. Even in a demagnetized magnetic molded body, the state in which the easy magnetization axis of each magnet particle in the magnetic molded body is oriented in the same direction as the magnetic field H is maintained. The demagnetization mechanism for demagnetizing the magnetic molded body may be provided as part of the manufacturing apparatus 1, or it may be provided as a separate component from the manufacturing apparatus 1. The configuration of the demagnetization mechanism is not limited. Subsequently, the demagnetized magnetic molded body may be heated to form a cured product of the magnetic molded body. When a magnetic molded body is used in the manufacture of bonded magnets, the material M may contain a thermosetting resin. Therefore, a cured product of the magnetic molded body may be formed by thermosetting the thermosetting resin in the magnetic molded body. Subsequently, the cured product of the magnetic molded body may be magnetized by applying a magnetic field that is oriented in the same direction as the magnetic field H to the cured product of the magnetic molded body. By magnetizing the cured product of the magnetic molded body, a permanent magnet (an anisotropic magnet magnetized in a specific direction) is obtained. The magnetic molded body formed through the compression step of material M and the application step of a magnetic field H may be a completed anisotropic bonded magnet. In this case, the demagnetization step described above may not be performed.

[0053] When a magnetic molded body is used in the manufacture of a sintered magnet, the magnetic molded body may be sintered to form a sintered body. The sintered body may be used as a permanent magnet (an anisotropic magnet magnetized in a specific direction). Before the magnetic molded body is sintered, it may be degreased by heating it at a temperature lower than its sintering temperature. The sintered body may be magnetized by applying a magnetic field that is oriented in the same direction as the magnetic field H mentioned above. The magnetized sintered body may be used as a permanent magnet.

[0054] Next, the formed magnetic molded body is removed from the mold 2. For example, first the first pressing mechanism 33 removes the first punch 31 from the mold 2. Then, the second pressing mechanism 34 moves the second punch 32 from the end face 22 toward the end face 21 of the mold 2. As a result, the magnetic molded body is pushed out by the second punch 32 and removed from the space S outside through the opening formed in the end face 21.

[0055] [Mechanism of Action and Effects] In the magnetic molded body manufacturing apparatus 1, a first yoke 6 is positioned between the first coil 4 and the mold 2, and the first yoke 6 is movable so that its position relative to the first coil 4 changes. When the first yoke 6 is positioned in a magnetic field H, the first yoke 6 has the function of collecting the magnetic field lines (magnetic flux) of the magnetic field H. Therefore, by moving the first yoke 6 and changing its position, the direction and strength of the magnetic field H applied to the material M in the mold 2 can be easily controlled. Thus, the magnetization direction of the magnetic molded body can be easily changed by changing the position of the first yoke 6, without changing the position and orientation of the mold 2, the first coil 4, and the second coil, for example. Thus, the magnetization direction of the magnetic molded body can be easily changed according to the manufacturing apparatus 1.

[0056] The coil axes of the first coil 4 and the second coil 5 are aligned in the direction in which the first coil 4 and the second coil 5 are aligned (X-axis direction), and the first yoke 6 is movable in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned (Z-axis direction). When the first yoke 6 is moved in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned, the direction of the magnetic field H changes significantly compared to when the first yoke 6 is moved in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned. Therefore, the magnetization direction of the magnetic molded body can be changed more efficiently with the manufacturing apparatus 1.

[0057] The manufacturing apparatus 1 includes a second yoke 7 positioned between the second coil 5 and the mold 2. The second yoke 7 is movable so that its position relative to the second coil 5 changes. This allows for a wider variety of ways in which the direction and intensity of the magnetic field H applied to the material M in the mold 2 can be changed, enabling the realization of a more appropriate magnetization direction for the magnetic molded body depending on the application of the permanent magnet.

[0058] The coil axes of the first coil 4 and the second coil 5 are aligned in the direction in which the first coil 4 and the second coil 5 are aligned (X-axis direction), and the second yoke 7 is movable in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned (Z-axis direction). When the second yoke 7 is moved in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned, the direction of the magnetic field H changes significantly compared to when the second yoke 7 is moved in a direction intersecting the direction in which the first coil 4 and the second coil 5 are aligned. Therefore, the magnetization direction of the magnetic molded body can be changed more efficiently with the manufacturing apparatus 1.

[0059] The compression mechanism 3 has a first punch 31 and a second punch 32 that face each other. The first yoke 6 and the second yoke 7 are each movable in the opposing direction of the first punch 31 and the second punch 32. This allows for a more efficient change in the magnetization direction of the magnetic molded body.

[0060] The first yoke 6 is movable so as to approach the first punch 31 in the opposing direction of the first punch 31 and the second punch 32. The second yoke 7 is movable so as to approach the second punch 32 in the opposing direction of the first punch 31 and the second punch 32. This allows the direction of the magnetic field H to be tilted with respect to the perpendicular direction, even when, for example, the first coil 4 and the second coil are arranged side by side in a direction perpendicular to the opposing direction of the first punch 31 and the second punch 32.

[0061] Each of the first yoke 6 and the second yoke 7 is movable so as to approach the second punch 32 in the opposing direction of the first punch 31 and the second punch 32. This makes it possible to increase the strength of the magnetic field H in the region of space S (material M of the magnetic molded body) within the mold 2 that is located near the second punch 32. In other words, the strength of the magnetic field H applied to the material M within the mold 2 can be easily controlled.

[0062] In the method for manufacturing a magnetic molded body according to this embodiment, the step of moving the first yoke 6 is performed before the step of applying the magnetic field H. As a result, for the reasons mentioned above, the direction and intensity of the magnetic field H applied to the material M in the mold 2 during the step of applying the magnetic field H can be easily controlled. This makes it possible to easily change the magnetization direction of the magnetic molded body.

[0063] [Differentiation] This disclosure is not limited to the embodiments described above. Modifications of the embodiments described above will be described below. For example, in the embodiments described above, both the first yoke 6 and the second yoke 7 were movable, but one of the first yoke 6 and the second yoke 7 may be movable while the other is not (it may be fixed). Furthermore, even if both the first yoke 6 and the second yoke 7 are movable, only one of them may be movable.

[0064] The first yoke 6 only needs to be movable so that its position relative to the first coil 4 changes, and the direction of movement of the first yoke 6 is not limited. The second yoke 7 only needs to be movable so that its position relative to the second coil 5 changes, and the direction of movement of the second yoke 7 is not limited. For example, each of the first yoke 6 and the second yoke 7 may be movable in the X-axis direction in which the first coil 4 and the second coil 5 are aligned, or may be movable in a direction that intersects the X-axis and Z-axis directions when viewed from the Y-axis direction.

[0065] The first yoke 6 and the second yoke 7 may be rotatable about an axis along a predetermined direction. In this case, the first moving mechanism 8 may have a shaft portion extending in a predetermined direction connected to the first yoke 6, and a drive unit such as a motor that rotates the shaft portion with the predetermined direction as the axial direction. Similarly, the second moving mechanism 9 may have a shaft portion extending in a predetermined direction connected to the second yoke 7, and a drive unit such as a motor that rotates the shaft portion with the predetermined direction as the axial direction.

[0066] The coil axes of the first coil 4 and the second coil 5 do not necessarily have to be aligned in the direction in which the first coil 4 and the second coil 5 are aligned, and may be inclined. Inside each of the first coil 4 and the second coil 5, there may be a yoke (for example, an iron core) separate from the first yoke 6 and the second yoke 7.

[0067] In the method for manufacturing a magnetic molded body, the order in which the steps of moving the first yoke 6 and the second yoke 7, applying a magnetic field H, and compressing the material M are performed is not limited. For example, the step of moving the first yoke 6 and the second yoke 7 may be performed together with the step of applying a magnetic field H. That is, the movement of the first yoke 6 and the second yoke 7 may be performed simultaneously with the application of the magnetic field H. In this case, the first yoke 6 and the second yoke 7 may be moved continuously by the first moving mechanism 8 and the second moving mechanism 9. By continuously moving the first yoke 6 and the second yoke 7, the magnetic powder in the material M of the magnetic molded body can be loosened (dispersed), and the direction of the applied magnetic field H can be dynamically changed.

[0068] The step of applying a magnetic field H may be performed together with the step of compressing the material M, or it may be performed before the step of compressing the material M. The steps of moving the first yoke 6 and the second yoke 7 may be performed together with the step of compressing the material M, or it may be performed before the step of compressing the material M.

[0069] In the process of moving the first yoke 6 and the second yoke 7, the first moving mechanism 8 may move the first yoke 6 closer to the second punch 32 in the Z-axis direction, and the second moving mechanism 9 may move the second yoke 7 closer to the first punch 31 in the Z-axis direction. Alternatively, in the process of moving the first yoke 6 and the second yoke 7, the first moving mechanism 8 may move the first yoke 6 closer to the first punch 31 in the Z-axis direction, and the second moving mechanism 9 may move the second yoke 7 closer to the first punch 31 in the Z-axis direction. The first yoke 6 and the second yoke 7 may be moved by mechanical devices such as the first moving mechanism 8 and the second moving mechanism 9, or they may be moved manually by an operator. [Explanation of Symbols]

[0070] 1...Manufacturing equipment (manufacturing equipment for magnetic molded bodies), 2...Mold, 3...Compression mechanism, 4...First coil, 5...Second coil, 6...First yoke, 7...Second yoke, 31...First punch, 32...Second punch, H...Magnetic field, M...Material.

Claims

1. A mold into which the material for a magnetic mold containing magnetic powder is supplied, A compression mechanism for compressing the material supplied to the mold, A first coil and a second coil are arranged so as to sandwich the mold, The first coil and the mold are disposed between the first coil and the mold, The first yoke is movable such that the position of the first yoke relative to the first coil changes. Manufacturing equipment for magnetic molded bodies.

2. The coil axes of the first coil and the second coil are aligned in the direction in which the first coil and the second coil are aligned. The first yoke is movable in a direction that intersects the direction in which the first coil and the second coil are aligned. The apparatus for manufacturing a magnetic molded body according to claim 1.

3. The present invention further comprises a second yoke positioned between the second coil and the mold, The second yoke is movable such that the position of the second yoke relative to the second coil changes. The apparatus for manufacturing a magnetic molded body according to claim 1 or 2.

4. The coil axes of the first coil and the second coil are aligned in the direction in which the first coil and the second coil are aligned. The second yoke is movable in a direction that intersects the direction in which the first coil and the second coil are aligned. The apparatus for manufacturing a magnetic molded body according to claim 3.

5. The compression mechanism has a first punch and a second punch facing each other, The first yoke and the second yoke are each movable in the opposing directions of the first punch and the second punch. The apparatus for manufacturing a magnetic molded body according to claim 3.

6. The first yoke is movable so as to approach the first punch in the opposing direction, The second yoke is movable so as to approach the second punch in the opposing direction. The apparatus for manufacturing a magnetic molded body according to claim 5.

7. Each of the first yoke and the second yoke is movable so as to approach the second punch in the opposing direction. The apparatus for manufacturing a magnetic molded body according to claim 5.

8. A method for manufacturing a magnetic molded body using the magnetic molded body manufacturing apparatus described in claim 1 or 2, A step of supplying the material to the mold, A step of moving the first yoke so that the position of the first yoke relative to the first coil changes, The process includes applying a magnetic field to the material supplied to the mold using the first coil and the second coil, The step of moving the first yoke is performed before the step of applying the magnetic field, or together with the step of applying the magnetic field. A method for manufacturing a magnetic molded body.

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