Method for producing bonded magnet

Abstract

This method for producing a bonded magnet includes: a molding step of compressing a magnetic material supplied into a mold unit by a compression device to mold a magnetic molded body; a mold taking-out step of taking out the mold unit from the compression device; a thermosetting step of thermosetting a thermosetting resin by heating the mold unit to obtain a bonded magnet; and a magnet taking-out step of taking out the bonded magnet from the mold unit.

Description

Method for manufacturing bonded magnet

[0001] The present disclosure relates to a method for manufacturing a bonded magnet.

[0002] A bonded magnet, which is a permanent magnet, is formed from a magnetic material containing magnet powder and a thermosetting resin. Patent Document 1 discloses an example of a method for manufacturing a bonded magnet. In the manufacture of a bonded magnet, first, a magnetic material containing magnet powder and a thermosetting resin is supplied into a mold. Subsequently, the magnetic material in the mold is compressed to form a magnetic molded body. Then, the magnetic molded body is taken out of the mold, and the bonded magnet is obtained by heating the magnetic molded body to thermally cure the thermosetting resin.

[0003] Japanese Patent No. 7298804

[0004] When compressing and molding the magnetic material in the mold, it is conceivable to manufacture a bonded magnet by heating the magnetic material to thermally cure the thermosetting resin. That is, it is conceivable to heat the magnetic material while compressing the magnetic molded body by a compression device. In this case, since the thermosetting resin is in a thermally cured state, it becomes easier to take out the bonded magnet from the mold. However, although the compression of the magnetic material by the compression device is completed in a short time, it takes time to heat the magnetic material to thermally cure the thermosetting resin. Therefore, even when the compression of the magnetic material by the compression device is completed, it is necessary to keep the compression device on standby until the thermal curing of the thermosetting resin is completed.

[0005] Therefore, the present disclosure will describe a method for manufacturing a bonded magnet that can manufacture a bonded magnet more efficiently.

[0006] One embodiment of the method for manufacturing a bonded magnet according to the present disclosure is [1] "A method for manufacturing a bonded magnet from a magnetic material comprising magnetic powder and a thermosetting resin, comprising: a molding step of compressing the magnetic material supplied into a mold unit with a compression device to form a magnetic molded body from the magnetic material; a mold removal step of removing the mold unit containing the magnetic molded body from the compression device; a thermosetting step of heating the removed mold unit to thermoset the thermosetting resin to obtain the bonded magnet from the magnetic molded body; and a magnet removal step of removing the bonded magnet from the mold unit."

[0007] In this manufacturing method, after the magnetic molded body is formed by a compression device, the mold unit is removed from the compression device. The mold unit removed from the compression device is then heated to heat-cur the thermosetting resin. This allows the compression device to compress the magnetic material in other mold units while the mold unit is being heated and the thermosetting resin is being heat-cured. Furthermore, in this manufacturing method, the bonded magnets removed from the mold unit during the magnet removal process have their thermosetting resins heat-cured. Therefore, the bonded magnets can be easily removed from the mold unit. Thus, this method for manufacturing bonded magnets allows for more efficient production.

[0008] The above method for manufacturing a bonded magnet may also be [2] "the method for manufacturing a bonded magnet as described in [1] above, wherein in the molding step, the mold unit is fitted into the fitting hole of a fitting mold having a fitting hole, the magnetic material inside the mold unit is compressed while the mold unit is fitted into the fitting hole, and the mold removal step is to remove the mold unit from the fitting mold and the compression device." In this method for manufacturing a bonded magnet, the magnetic material inside the mold unit is compressed while the mold unit is fitted into the fitting hole of the fitting mold. In other words, the magnetic material is compressed while the mold unit is surrounded by the fitting mold. As a result, even if the mold unit tries to deform when the magnetic material is compressed, the inner wall surface of the fitting hole of the fitting mold can press down on the outer surface of the mold unit, thereby suppressing deformation of the mold unit. Furthermore, since the mold unit can be held down by the fitting mold, there is no need to increase the thickness of the mold unit for the purpose of suppressing deformation of the mold unit. In other words, the thickness of the mold unit can be reduced. This allows the mold unit to heat up more quickly during the thermosetting process, enabling more efficient thermosetting of the thermosetting resin.

[0009] The above method for manufacturing bonded magnets may also be [3] "the method for manufacturing bonded magnets according to [1] or [2] above, wherein in the heat curing step, a plurality of mold units removed in the mold removal step are heated simultaneously." In this case, the method for manufacturing bonded magnets allows for heating multiple mold units at once, enabling the manufacturing of bonded magnets more efficiently.

[0010] The above method for manufacturing a bonded magnet may also be [4] "The mold unit includes a die having a through hole into which the magnetic material is supplied, a first punch inserted into the through hole from one end of the through hole, and a second punch inserted into the through hole from the other end of the through hole, wherein in the molding step, the magnetic material between the first punch and the second punch is compressed within the die by bringing the first punch and the second punch closer together, and in the magnet removal step, either the first punch or the second punch is removed from the die, and the bonded magnet is removed from the die by pushing out the bonded magnet with the other of the first punch or the second punch, the method for manufacturing a bonded magnet according to any one of [1] to [3] above." In this case, in the magnet removal step, the bonded magnet can be easily removed from the die by pushing out the bonded magnet with the first punch or the second punch.

[0011] The above method for manufacturing bonded magnets may also be [5] "the method for manufacturing bonded magnets according to any one of [1] to [4] above, wherein in the mold unit, a release layer having release properties for thermosetting resins is provided on the wall surface of the compression space for compressing the supplied magnetic material." In this case, the bonded magnets can be removed from the mold unit even more easily in the magnet removal step.

[0012] According to this disclosure, bonded magnets can be manufactured more efficiently.

[0013] Figure 1 is a block diagram showing an example of a bonded magnet manufacturing apparatus according to an embodiment. Figure 2 is a front view showing the schematic configuration of the compression apparatus in Figure 1. Figure 3 is a top view of the mold unit and fitting mold in Figure 2, viewed from the upper punch side. Figure 4(a) is a schematic diagram illustrating the preparation process. Figure 4(b) is a schematic diagram illustrating the molding process. Figure 5(a) is a schematic diagram illustrating the mold removal process. Figure 5(b) is a schematic diagram illustrating the thermosetting process. Figure 6 is a schematic diagram illustrating the magnet removal process.

[0014] The following describes exemplary embodiments with reference to the drawings. In each drawing, identical or equivalent elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0015] [Overall Configuration of the Manufacturing Apparatus] The bond magnet manufacturing system 1 shown in Figure 1 is an apparatus for manufacturing bond magnets. In manufacturing system 1, magnetic material supplied into mold unit K1 (see Figure 2, etc.) is compressed to form a magnetic molded body from the magnetic material. Subsequently, manufacturing system 1 heats mold unit K1 to form bond magnets from the magnetic molded body. Finally, the bond magnets are removed from mold unit K1.

[0016] The magnetic material used as the raw material for bonded magnets includes magnetic powder and thermosetting resin. The magnetic powder contained in the magnetic material is, for example, Nd-Fe-B magnet (Nd ２ Fe １４ (Alloys such as B), samarium-iron-nitrogen magnets (Sm ２ Fe １７ N ３ (Sm alloys, etc.), samarium-cobalt magnets (Sm ２ Co １７ (Alloys such as), praseodymium magnets (PrCo ５ The magnet may be an alloy such as a ferrite magnet. The thermosetting resin may be, for example, an epoxy resin. In addition to the magnet powder and thermosetting resin, the magnetic material may contain components such as 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 magnetic material may further contain a thermoplastic resin. The magnetic material may be a compound containing the magnet powder and the thermosetting resin. The magnetic material may be pre-mixed to a substantially uniform state. The magnetic material may be a powder, a tablet, or a paste.

[0017] The manufacturing system 1 includes a compression device 10 and a heating device 20. As shown in Figure 2, the compression device 10 compresses the magnetic material 2 supplied into the mold unit K1 to form a magnetic molded body 2A from the magnetic material 2. The compression device 10 includes a first pressurizing mechanism 11 and a second pressurizing mechanism 12. The first pressurizing mechanism 11 and the second pressurizing mechanism 12 face each other with a predetermined distance between them. Hereinafter, the direction in which the first pressurizing mechanism 11 and the second pressurizing mechanism 12 face each other will be referred to as the Z-axis direction. One direction perpendicular to the Z-axis direction will be referred to as the X-axis direction, and the direction perpendicular to both the Z-axis direction and the X-axis direction will be referred to as the Y-axis direction. In this embodiment, the Z-axis direction will be the vertical direction. In the vertical direction (Z-axis direction), the side on which the first pressurizing mechanism 11 is provided relative to the second pressurizing mechanism 12 will be referred to as "up," and the opposite side will be referred to as "down."

[0018] In the compression device 10, a mold unit K1 containing the magnetic material 2 is positioned between the first pressurizing mechanism 11 and the second pressurizing mechanism 12. The mold unit K1 is positioned such that the upper punch (first punch) K11 faces the first pressurizing mechanism 11 and the lower punch (second punch) K12 faces the second pressurizing mechanism 12. The mold unit K1 is detachable from the compression device 10.

[0019] The first pressurizing mechanism 11 is a device that moves the upper punch K11 of the mold unit K1 along the Z-axis direction. The first pressurizing mechanism 11 may be a hydraulic mechanism. The second pressurizing mechanism 12 is a device that moves the lower punch K12 of the mold unit K1 along the Z-axis direction. The first pressurizing mechanism 11 moves the upper punch K11 toward the second pressurizing mechanism 12. The second pressurizing mechanism 12 moves the lower punch K12 toward the first pressurizing mechanism 11. As a result, the magnetic material 2 inside the mold unit K1 is compressed, and a magnetic molded body 2A is formed from the magnetic material 2. Alternatively, the compression device 10 may compress the magnetic material 2 inside the mold unit K1 by moving the upper punch K11 with the first pressurizing mechanism 11 while the lower punch K12 is fixed.

[0020] As shown in Figures 2 and 3, the mold unit K1 comprises a die K10, an upper punch K11, and a lower punch K12. The die K10 has a through hole K10a. In this embodiment, the through hole K10a is, for example, a hole with a rectangular cross-section. The cross-sectional shape of the through hole K10a is not particularly limited. Magnetic material 2 is supplied into the through hole K10a of the die K10. The mold unit K1 is positioned between the first pressurizing mechanism 11 and the second pressurizing mechanism 12 such that the through hole K10a of the die K10 extends in the Z-axis direction.

[0021] The upper punch K11 has a columnar shape. The cross-sectional shape of the upper punch K11 matches the cross-sectional shape of the through hole K10a provided in the die K10. In this embodiment, the upper punch K11 has a rectangular prism shape as an example. The upper punch K11 has an end face K11a at one end in the extending direction. The upper punch K11 is inserted into the through hole K10a provided in the die K10 from one end of the through hole K10a, with the end face K11a leading. In the upper punch K11, the end opposite to the end on which the end face K11a is provided is pressed by the first pressurizing mechanism 11.

[0022] The lower punch K12 has a columnar shape. The cross-sectional shape of the lower punch K12 matches the cross-sectional shape of the through hole K10a provided in the die K10. In this embodiment, the lower punch K12 has a rectangular prism shape as an example. The lower punch K12 has an end face K12a at one end in the extending direction. The lower punch K12 is inserted into the through hole K10a provided in the die K10 from the other end of the through hole K10a, with the end face K12a leading. In the lower punch K12, the end opposite to the end on which the end face K12a is provided is pressed by the second pressurizing mechanism 12.

[0023] The end face K11a of the upper punch K11 becomes the surface that presses the magnetic material 2 supplied into the through hole K10a of the die K10. The end face K12a of the lower punch K12 also becomes the surface that presses the magnetic material 2 supplied into the through hole K10a of the die K10. Within the through hole K10a of the die K10, the space between the end face K11a of the upper punch K11 and the end face K12a of the lower punch K12 becomes a compression space R that compresses the magnetic material 2 supplied to the mold unit K1. The upper punch K11 and the lower punch K12 are pressed by the compression device 10, compressing the magnetic material 2 in the compression space R and forming a magnetic molded body 2A.

[0024] In the mold unit K1, a release layer H is provided on the wall surface of the compression space R, which has release properties for the thermosetting resin contained in the magnetic material 2. The wall surface of the compression space R is composed of the inner wall surface of the through hole K10a of the die K10, the end face K11a of the upper punch K11, and the end face K12a of the lower punch K12. In other words, the release layer H is provided on the inner wall surface, end face K11a, and end face K12a of the through hole K10a. The release layer H provided on the inner wall surface of the through hole K10a may be provided over the entire area of ​​the inner wall surface of the through hole K10a (the entire area in the extending direction of the through hole K10a). Alternatively, the release layer H provided on the inner wall surface of the through hole K10a may be provided only in the part of the inner wall surface of the through hole K10a where the magnetic molded body 2A is present when the magnetic molded body 2A is heated by the heating device 20.

[0025] The release layer H provided on the wall surface of the compression space R is made of a material that has higher release properties from the thermosetting resin contained in the magnetic material 2 than the components constituting the mold unit K1 (die K10, upper punch K11, lower punch K12). For example, the release layer H provided on the wall surface of the compression space R may be made of fluororesin (Teflon®). The release layer H is made of a material that can withstand the heat applied in the thermosetting process described later.

[0026] In this embodiment, when the magnetic molded body 2A is molded by the compression device 10, a fitting mold K2 is further used. The fitting mold K2 has a through hole (fitting hole) K2a. The through hole K2a is shaped so that the die K10 can be fitted inside when the die K10 is positioned relative to the fitting mold K2 such that the extending direction of the through hole K2a coincides with the extending direction of the through hole K10a of the die K10. In other words, the cross-sectional shape of the through hole K2a matches the outer shape of the die K10. The fitting mold K2 surrounds the die K10 in a direction perpendicular to the Z-axis direction when the mold unit K1 is positioned between the first pressurizing mechanism 11 and the second pressurizing mechanism 12 of the compression device 10. The compression device 10 compresses the magnetic material 2 inside the mold unit K1 (die K10) with the mold unit K1 (die K10) fitted into the through hole K2a of the fitting mold K2 to mold the magnetic molded body 2A.

[0027] The heating device 20 shown in Figure 1 heats the magnetic molded body 2A after it has been molded by the compression device 10 to heat-cur (completely cure) the thermosetting resin contained in the magnetic molded body 2A. This yields a bonded magnet 2B from the magnetic molded body 2A. Here, the heating device 20 heats the thermosetting resin contained in the magnetic molded body 2A by heating the mold unit K1 after it has been removed from the compression device 10 and the fitting mold K2. For example, the heating device 20 may be equipped with a heater for heating the mold unit K1.

[0028] [Method for Manufacturing Bonded Magnets] The method for manufacturing bonded magnet 2B will be described below. The method for manufacturing bonded magnet 2B includes a preparation step, a molding step, a mold removal step, a heat curing step, and a magnet removal step, and each step is performed in this order.

[0029] In the preparation step, a mold unit K1 for housing the magnetic material 2 is prepared, as shown in Figure 4(a). For example, the magnetic material 2 is supplied into the through hole K10a with the lower punch K12 attached to the die K10 and the upper punch K11 removed. After the magnetic material 2 is supplied, the upper punch K11 may be attached to the die K10 to prepare the mold unit K1 for housing the magnetic material 2. For example, the magnetic material 2 may be supplied by a supply device or the like. Multiple mold units K1 for housing the magnetic material 2 may be prepared in the preparation step.

[0030] In the molding process, as shown in Figure 4(b), the mold unit K1 is fitted into the through hole K2a of the fitting mold K2, and the mold unit K1 is positioned between the first pressurizing mechanism 11 and the second pressurizing mechanism 12 of the compression device 10. When positioning the mold unit K1, the first pressurizing mechanism 11 of the compression device 10 may be moved to a position away from the second pressurizing mechanism 12 in order to secure space for the positioning work. The fitting mold K2 may be provided on the compression device 10. Alternatively, the fitting mold K2 may be provided separately from the compression device 10 and attached to the fitting mold K2 before the mold unit K1 is positioned on the compression device 10.

[0031] After the mold unit K1 is positioned, in the molding process, the compression device 10 compresses the magnetic material 2 between the upper punch K11 and the lower punch K12 within the die K10 by using the first pressurizing mechanism 11 and the second pressurizing mechanism 12 to bring the upper punch K11 and the lower punch K12 closer together. In this way, the compression device 10 molds a magnetic molded body 2A from the magnetic material 2. The pressurizing time for which the compression device 10 pressurizes the magnetic material 2 in the molding process may be, for example, less than one minute.

[0032] In the mold removal process, as shown in Figure 5(a), the mold unit K1 containing the magnetic molded body 2A is removed from the compression device 10 and the fitting mold K2. In the thermosetting process, as shown in Figure 5(b), the thermosetting resin contained in the magnetic molded body 2A is thermoset (completely cured) by heating the mold unit K1 removed in the mold removal process, thereby obtaining a bonded magnet 2B from the magnetic molded body 2A. In the thermosetting process, multiple mold units K1 removed in the mold removal process may be heated simultaneously. In the thermosetting process, for example, the magnetic molded body 2A may be heated at a temperature of about 150° to 200° for several tens of minutes to about 1 hour.

[0033] In the magnet removal process, the bonded magnet 2B is removed from the mold unit K1. Alternatively, in the magnet removal process, as shown in Figure 6, the upper punch K11 may be removed from the die K10, and the bonded magnet 2B may be pushed out by the lower punch K12, thereby removing the bonded magnet 2B from the through hole K10a of the die K10. Alternatively, the lower punch K12 may be removed from the die K10, and the bonded magnet 2B may be pushed out by the upper punch K11, thereby removing the bonded magnet 2B from the through hole K10a of the die K10.

[0034] [Effects] As described above, in the method for manufacturing bonded magnets 2B, after the magnetic molded body 2A is molded by the compression device 10, the mold unit K1 is removed from the compression device 10. Then, the mold unit K1 removed from the compression device 10 is heated by the heating device 20 to heat-cur the thermosetting resin contained in the magnetic material 2 (magnetic molded body 2A). As a result, while the mold unit K1 is being heated and the thermosetting resin is being heat-cured, the compression device 10 can compress the magnetic material 2 in the other mold units K1. Furthermore, in this method for manufacturing bonded magnets 2B, the bonded magnets 2B removed from the mold unit K1 in the magnet removal process are in a state where the thermosetting resin has been heat-cured. Therefore, it is possible to suppress the bonded magnets 2B from sticking to the mold unit K1 and to easily remove the bonded magnets 2B from the mold unit K1. Thus, this method for manufacturing bonded magnets 2B allows for more efficient production of bonded magnets 2B.

[0035] Furthermore, in the manufacturing method of bonded magnet 2B, the magnetic material inside the mold unit K1 is compressed by the compression device 10 while the mold unit K1 is fitted into the through hole K2a of the fitting mold K2. In other words, the magnetic material 2 is compressed while the mold unit K1 is surrounded by the fitting mold K2. As a result, even if the mold unit K1 attempts to deform when the magnetic material 2 is compressed, the inner wall surface of the through hole K2a of the fitting mold K2 can press down on the outer surface of the mold unit K1, thereby suppressing deformation of the mold unit K1. In addition, since the mold unit K1 can be held down by the fitting mold K2, there is no need to increase the thickness of the mold unit K1 in order to suppress deformation of the mold unit K1. In other words, the thickness of the mold unit K1 can be reduced. As a result, when the mold unit K1 is heated in the thermosetting process, the temperature of the mold unit K1 can be raised more quickly, and the thermosetting resin can be thermoset more efficiently.

[0036] In the thermosetting process, the heating device 20 may simultaneously heat multiple mold units K1 that were removed in the mold removal process. In this case, the method for manufacturing bonded magnets 2B allows for heating multiple mold units K1 at once, enabling more efficient production of bonded magnets 2B.

[0037] The mold unit K1 comprises a die K10, an upper punch K11, and a lower punch K12. In the magnet removal process, the upper punch K11 is removed from the die K10, and the bonded magnet 2B is pushed out by the lower punch K12, thereby removing the bonded magnet 2B from the die K10. This allows the bonded magnet 2B to be easily removed from inside the die K10 in the manufacturing method of the bonded magnet 2B.

[0038] In the mold unit K1, a release layer H is provided on the wall surface of the compression space R. In this case, when removing the bonded magnet 2B in the magnet removal process, the bonded magnet 2B can be removed from the mold unit K1 more easily.

[0039] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above. For example, a magnetic field may be applied to the magnetic material 2 when performing a molding process to form a magnetic molded body 2A from the magnetic material 2.

[0040] 2...Magnetic material, 2A...Magnetic molded body, 2B...Bonded magnet, 10...Compression device, H...Release layer, K1...Mold unit, K10...Die, K10a...Through hole, K11...Upper punch (first punch), K12...Lower punch (second punch), K2...Fitting mold, K2a...Through hole (fitting hole), R...Compression space.

Claims

1. A method for manufacturing a bonded magnet from a magnetic material comprising magnetic powder and a thermosetting resin, comprising: a molding step of compressing the magnetic material supplied into a mold unit with a compression device to form a magnetic molded body from the magnetic material; a mold removal step of removing the mold unit containing the magnetic molded body from the compression device; a thermosetting step of heating the removed mold unit to thermoset the thermosetting resin to obtain the bonded magnet from the magnetic molded body; and a magnet removal step of removing the bonded magnet from the mold unit.

2. The method for manufacturing a bonded magnet according to claim 1, wherein in the molding step, the mold unit is fitted into the fitting hole of a fitting mold having a fitting hole, the magnetic material inside the mold unit is compressed to form the magnetic molded body while the mold unit is fitted into the fitting hole, and in the mold removal step, the mold unit is removed from the fitting mold and the compression device.

3. The method for manufacturing a bonded magnet according to claim 1, wherein in the heat curing step, a plurality of mold units removed in the mold removal step are heated simultaneously.

4. The method for manufacturing a bonded magnet according to claim 1, wherein the mold unit includes a die having a through hole into which the magnetic material is supplied, a first punch inserted into the through hole from one end of the through hole, and a second punch inserted into the through hole from the other end of the through hole, wherein in the molding step, the magnetic material between the first punch and the second punch is compressed within the die by bringing the first punch and the second punch closer together, and in the magnet removal step, the bonded magnet is removed from the die by removing either the first punch or the second punch from the die and pushing out the bonded magnet with the other of the first punch or the second punch.

5. The method for manufacturing a bonded magnet according to any one of claims 1 to 4, wherein a release layer having release properties for thermosetting resins is provided on the wall surface of the compression space for compressing the supplied magnetic material in the mold unit.

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