JP6520979B2 - Method and system for manufacturing anisotropic bonded magnet - Google Patents

Description

  The present invention relates to methods and systems for manufacturing anisotropic bonded magnets.

  A bonded magnet formed by solidifying and forming a magnetic powder and a resin as a binder of the magnetic powder has advantages of high dimensional accuracy and high degree of freedom in shape as compared with a sintered magnet. The bonded magnet includes an isotropic bonded magnet using an isotropic material having no magnetic anisotropy as a magnetic powder, and an anisotropic bonded magnet using a material having a magnetic anisotropy as a magnetic powder. . An anisotropic bonded magnet, in which the magnetization directions of the magnetic powder are aligned in a fixed direction, has relatively better magnetic properties than isotropic bonded magnets.

  Various methods have been proposed as a method of manufacturing an anisotropic bonded magnet (e.g., Patent Documents 1 and 2).

  In Patent Document 1, after a mixture of magnetic powder and thermosetting resin is filled in a mold for molding, the desired shape is obtained by compression molding of the mixture in a state in which the mold is maintained in a magnetic field. Manufacturing an anisotropic bonded magnet.

  In Patent Document 2, an anisotropic bonded magnet is formed by extruding a mixture of anisotropic magnetic powder and resin while applying a magnetic field using an extrusion molding machine in which a coil for applying a magnetic field is disposed at an extrusion port. Manufacture.

JP, 2010-199222, A JP, 2013-105964, A Chinese Patent Application Publication No. 104441667 Unexamined-Japanese-Patent No. 11-8109 Unexamined-Japanese-Patent No. 2003-23191 Unexamined-Japanese-Patent No. 2-296311 Japanese Patent Application Laid-Open No. 1-128404

  However, Patent Document 1 has a problem that a new mold is required each time the shape of the anisotropic bonded magnet to be manufactured changes. In addition, there is also a problem that the orientation of the magnetic powder is disturbed due to molding by a mold.

  On the other hand, Patent Document 2 has a problem that the shape that can be molded is limited. There is also a problem that the orientation of the magnetic powder is disturbed by extrusion molding.

  In addition, patent documents 3-7 exist as a document relevant to manufacture of the anisotropic bonded magnet in this application.

  Patent Document 3 discloses that an anisotropic bonded magnet is manufactured using a three-dimensional printing and molding machine, but an anisotropic bonded magnet is manufactured by providing a magnetic field generator in the printing and molding machine. Since there is a space between the magnetic field generator and the bond magnet, there is a problem that it is difficult to accurately orient the magnetic field of the bond magnet.

  Heat treatment in a magnetic field to improve the orientation of magnetic alloys is described in US Pat. However, Patent Document 4 only discloses producing a rare earth permanent magnet having magnetic anisotropy by performing heat treatment in a predetermined magnetic field when heat treating and crystallizing an amorphous alloy. There is no disclosure or suggestion to produce an anisotropic bonded magnet by applying a magnetic field orientation treatment in a heating environment to a bonded magnet molded using the method of a three-dimensional molding machine as in the present application. Further, in Patent Document 5, heat treatment in a magnetic field is only used to form a single magnetic domain in the magnetization direction of the pinned magnetic layer by an exchange coupling magnetic field, and a method of a three-dimensional forming machine is used as in the present application. There is no disclosure or suggestion to produce an anisotropic bonded magnet by subjecting the molded bonded magnet to magnetic orientation processing in a heating environment. Furthermore, even in Patent Documents 6 and 7, the technology relates to the manufacture of permanent magnets, and the application to a bonded magnet as in the present application is neither disclosed nor suggested.

  The present invention has been made in view of such circumstances. By using the method of the three-dimensional molding machine, no mold is required, and it is not necessary to manufacture a new mold each time the shape changes, Manufacturing method and manufacturing of anisotropic bonded magnet capable of easily manufacturing anisotropic bonded magnet having arbitrary shape and capable of performing magnetic field orientation accurately and manufacturing anisotropic bonded magnet having good magnetic characteristics It aims to provide a system.

  A method of manufacturing an anisotropic bonded magnet according to the present invention is a method of manufacturing an anisotropic bonded magnet, wherein a mixture of a magnetic powder and a molten thermoplastic resin is applied from a nozzle to a laminating table, the nozzle and the laminating table Forming a laminated body by extruding and laminating while relatively moving the material in three dimensions, arranging a container containing the molded laminated body in a magnetic field area in a predetermined direction, and the thermoplastic resin Orienting a magnetic field in a fixed direction in the laminate in the container while maintaining a temperature above the melting point of the container, and orienting the magnetic field in the fixed direction while the laminate is below the melting point of the thermoplastic resin And the step of cooling to a temperature of

The system for producing an anisotropic bonded magnet according to the present invention is a system for producing an anisotropic bonded magnet, comprising: a nozzle for extruding a mixture of a magnetic powder and a molten thermoplastic resin; and the above extruded from the nozzle It has a stack table for receiving and stacking a mixture, and a moving mechanism for moving the nozzle and the stack table in three dimensions relatively, while moving the nozzle and the stack platform in three dimensions relatively A forming apparatus for laminating the mixture on the laminate table to form a laminate, a magnetic circuit for forming a magnetic field in a predetermined direction, and a heat treatment furnace that accommodates the magnetic circuit and is capable of adjusting an internal temperature; And orienting the magnetic field in the fixed direction in the laminate housed in the container while maintaining the temperature at or above the melting point of the thermoplastic resin in the heat treatment furnace, and then the laminate To the above While orienting the magnetic field of a constant direction, characterized in that the laminate comprises a magnetic field during the heat treatment device for cooling to a temperature below the melting point of the thermoplastic resin.
The system for producing an anisotropic bonded magnet according to the present invention is a system for producing an anisotropic bonded magnet, comprising: a nozzle for extruding a mixture of a magnetic powder and a molten thermoplastic resin; and the above extruded from the nozzle It has a stack table for receiving and stacking a mixture, and a moving mechanism for moving the nozzle and the stack table in three dimensions relatively, while moving the nozzle and the stack platform in three dimensions relatively A forming apparatus for laminating the mixture on the lamination table to form a laminated body, a magnetic circuit for forming a magnetic field in a predetermined direction between magnetic gaps, and a temperature in the magnetic gap provided in the magnetic gap Heat treatment means for enabling adjustment, the heat treatment means orienting the magnetic field in the predetermined direction in the laminate while maintaining the temperature above the melting point of the thermoplastic resin; After while orienting magnetic field of the predetermined direction to the laminate, characterized in that the laminate comprises a magnetic field during the heat treatment device for cooling to a temperature below the melting point of the thermoplastic resin.

In the present invention, a mixture of a magnetic powder and a molten thermoplastic resin is extruded from a nozzle onto a lamination table and laminated to form a laminated body (isotropic bonded magnet). At this time, the lamination process is performed while relatively moving the nozzle and the lamination table in three dimensions to form a laminate having a desired shape. Then, molded laminate was placed in a fixed direction of the magnetic field region magnetic circuit is formed, while maintaining a predetermined time or more thermoplastic resin melting point to orient the magnetic field of a fixed direction in the laminated body. Thereafter, the laminate is cooled to less than the melting point of the thermoplastic resin while being oriented in the magnetic field to produce an anisotropic bonded magnet.

  By moving the nozzle and the stacking table in three dimensions relative to each other so as to have the shape to be manufactured, it is possible to easily manufacture an anisotropic bonded magnet having a desired shape without using a mold. In addition, since the method of three-dimensional printing is used and it is not the conventional mold molding or extrusion molding, the orientation is not disturbed by molding pressure. In addition, the heat treatment in a magnetic field is performed on the molded laminate (isotropic bonded magnet), so the orientation accuracy is high. As a result, an anisotropic magnet having high precision magnetic characteristics is obtained.

  The method for producing an anisotropic bonded magnet according to the present invention is characterized in that, in the mixture, the magnetic powder has magnetic anisotropy.

  In the present invention, the magnetic powder of the mixture extruded from the nozzle has magnetic anisotropy. Therefore, it is possible to manufacture an anisotropic bonded magnet having good magnetic properties even if the orientation magnetic field in the heat treatment in a magnetic field is small.

  The method for producing an anisotropic bonded magnet according to the present invention is characterized in that the volume mixing ratio of the magnetic powder to the thermoplastic resin is in the range of 50:50 to 56.5: 43.5.

  In the present invention, the volume mixing ratio of the magnetic powder to the thermoplastic resin is in the range of 50:50 to 56.5: 43.5. When the proportion of the magnetic powder is large, the magnetic properties of the anisotropic bonded magnet to be manufactured are improved, but the lamination process for forming into a desired shape becomes difficult. Since the obtained magnetic properties and the ease of manufacture are in a contradictory relationship, the volume mixing ratio of the magnetic powder to the thermoplastic resin is set in the above range.

  In the method of producing an anisotropic bonded magnet according to the present invention, the material of the magnetic substance used as the magnetic powder is Sr ferrite, Ba ferrite, Sr-La-Co ferrite, Ca-La-Co ferrite, Sm-Fe-N-based alloy and R-T-B-based alloy (R is a rare earth element and must contain either Nd or Pr. T is a transition metal and must contain Fe. B is boron. A) selected from the group consisting of

  In the present invention, the material of the magnetic powder is Sr ferrite, Ba ferrite, Sr-La-Co ferrite, Ca-La-Co ferrite, Sm-Fe-N alloy, or R-T- It is a B-based alloy. When using these materials, by applying an orientation magnetic flux density of 1 to 2 times the residual magnetic flux density of a bonded magnet manufactured by a conventional method (mold molding, extrusion molding, etc.) in a heat treatment step in a magnetic field And magnetic properties equivalent to those of the bonded magnet manufactured in the conventional manufacturing process can be obtained.

  According to the present invention, it is possible to easily manufacture an anisotropic bonded magnet having an arbitrary shape in a short period of time because there is no need for a mold and it is not necessary to manufacture a new mold every time the shape changes. Even a ring-shaped anisotropic bonded magnet, which has hitherto required time and cost for mold making, can be manufactured in a short time and at low cost. Also, by applying a predetermined orientation magnetic flux density by heat treatment in a magnetic field, an anisotropic bonded magnet having good magnetic properties can be manufactured.

It is a perspective view which shows the structure of the laminated body shaping | molding apparatus in the manufacturing system of the anisotropic bonded magnet which concerns on this invention. It is sectional drawing which shows the structure of the formation machine which forms a resin molding. It is a partially broken perspective view which shows the structure of the heat processing apparatus in the magnetic field in the anisotropic bonded magnet system which concerns on this invention. It is a flowchart which shows the procedure of the manufacturing method of the anisotropic bonded magnet which concerns on this invention. It is a perspective view which shows the other structural example of the magnetic circuit in the heat processing apparatus in a magnetic field. It is sectional drawing which shows the other structural example of the heat processing apparatus in a magnetic field.

  Hereinafter, the present invention will be described in detail based on the drawings showing the embodiments. The system for manufacturing an anisotropic bonded magnet according to the present invention comprises a laminate forming apparatus 1 (see FIG. 1) for forming a laminate of a mixture of magnetic powder and a melted thermoplastic resin, and a molded laminate. A magnetic field heat treatment apparatus 3 (see FIG. 3) for applying a heat treatment apparatus in a magnetic field is provided.

  First, the configuration of the laminate molding apparatus 1 will be described with reference to FIG. In FIG. 1, reference numeral 11 denotes a rectangular base. Struts 12 are erected at the four corners of the base 11, and a rectangular plate-like stacking base 13 is supported by the struts 12. A laminate of a mixture of the magnetic powder and the melted thermoplastic resin is formed on the stacking table 13 as described later. In FIG. 1, two orthogonal side directions of the stacking table 13 are taken as an X direction and a Y direction, and a thickness direction of the stacking table 13 is taken as a Z direction.

  The tip of the nozzle 15 whose proximal end is connected to the heater 14 is positioned above the center of the stacking table 13. The upper portion of the heater 14 is in communication with the heat insulating cylinder 17 via the heat shield plate 16, and the upper surface portion of the heat insulating cylinder 17 is provided with a pair of rollers 18 having irregularities on the surface.

  A resin molded body R, which is a molded body of a magnetic powder and a thermoplastic resin, is introduced into the heater 14 via the heat insulating cylinder 17 by the rotating roller 18. The heater 14 heats the introduced resin molded body R to melt the thermoplastic resin, and supplies the mixture after melting to the nozzle 15. The nozzle 15 forms the laminate (bonded magnet) L by extruding the supplied mixture from its tip and sequentially laminating the mixture. The heat shield plate 16 prevents the heat from the heater 14 from being dissipated, and the heat insulating cylinder 17 prevents the resin molded body R from being cooled at the outside temperature. The formation mechanism of the resin molded body R will be described later.

  The heater 14 is provided with a guide 19 extending in the X direction, and a belt 20 having one end connected to a motor (not shown). The heater 14 and the nozzle 15 can be integrally moved in the X direction by the movement of the belt 20 in the X direction. The guide 19 is connected to a pedestal 21 movable in the Y direction by rotational driving of a ball screw (not shown). The heater 14 and the nozzle 15 can be integrally moved in the Y direction by movement of the pedestal 21 in the Y direction. By such a driving means, the nozzle 15 can be arbitrarily moved in the X and Y directions.

  A pair of guides 23 whose middles are penetrated to the pedestal 22 is fixedly provided in the stacking table 13 so as to extend in the Z direction. Further, a ball screw 24 is provided on the pedestal 22 so that the lamination base 13 can be moved in the Z direction by rotational driving of the ball screw 24.

  By means of the drive mechanism as described above, the stacking table 13 and the nozzle 15 can be moved relative to each other in three dimensions.

  In the embodiment described above, the nozzle 15 moves in the X direction and the Y direction, and the stacking table 13 moves in the Z direction. This configuration is an example, and the nozzle 15 is relative to the stacking table 13. And the nozzle 15 may be movable in the X direction, the Y direction, and the Z direction. For example, the laminating table 13 and the nozzle 15 may be movable. Any relative drive mechanism can be adopted as long as relative three-dimensional movement can be performed.

  FIG. 2 is a cross-sectional view showing the configuration of a forming machine 2 for forming a resin molded body R. As shown in FIG. The forming machine 2 has a cylinder 25, a hopper 26 provided at the base end of the cylinder 25, a screw 27 provided in the cylinder 25, and a mold 28 connected to the tip of the cylinder 25.

  In this forming machine 2, a resin molded body R is formed by extrusion molding. The magnetic powder and the thermoplastic resin to be the material of the resin molded body R are introduced into the cylinder 25 through the hopper 26. The screw 27 mixes the magnetic powder and the thermoplastic resin, extrudes it to the tip side, and supplies it to the mold 28. Then, a resin molded body R having a predetermined diameter is extruded from the mold 28.

  In the forming machine 2, an orientation coil may be provided around the mold 28. When an orientation coil is provided, the mixture is applied with a magnetic field from the orientation coil when passing through the die 28, and a resin compact R containing magnetic powder having magnetic anisotropy is obtained. The orientation coil is not a component essential to the present invention, and if sufficient orientation processing can be performed at the time of production of the anisotropic bonded magnet using the heat treatment apparatus 3 in a magnetic field described later, magnetic powder in the resin compact R In particular, the orientation treatment of is not necessary.

  Next, the configuration of the heat treatment apparatus 3 in a magnetic field will be described with reference to FIG. In FIG. 3, 31 is a heat treatment furnace. A magnetic circuit 32 is provided in the heat treatment furnace 31, and a temperature controller 38 is provided outside the heat treatment furnace 31.

  The magnetic circuit 32 includes a U-shaped yoke 33, a rectangular N-type permanent magnet 34 for orientation, provided on the lower surface (inner surface) of the upper piece 33a of the yoke 33, and the lower piece 33b of the yoke 33. S-shaped permanent magnet 35 for orientation in a rectangular shape provided on the upper surface (inner surface), a deflector plate 36 fixed to the lower surface of the N-type permanent magnet 34, and fixed on the upper surface of the S-type permanent magnet 35 And a magnetic shunt plate 37. The N-type permanent magnet 34 (the magnetic shunt plate 36) and the S-type permanent magnet 35 (the magnetic shunt plate 37) face each other in the vertical direction at a predetermined distance. The N-type permanent magnet 34 and the S-type permanent magnet 35 are magnets with little temperature change of the generated magnetic field strength even when the temperature becomes high, and are, for example, SmCo-based permanent magnets. Here, the N-type permanent magnet refers to a permanent magnet in which the surface facing the S-type permanent magnet at the top and bottom is the N pole, while the surface facing the S-type permanent magnet is S A permanent magnet that is a pole.

  With such a configuration, in the opposing region between the N-type permanent magnet 34 (the magnetic shunt plate 36) and the S-type permanent magnet 35 (the magnetic shunt plate 37), the magnetic flux in a fixed direction (direction from top to bottom) Flows. And the nonmagnetic container 40 which accommodated the laminated body L shape | molded by the laminated body shaping | molding apparatus 1 in this opposing area | region (magnetic field area | region of a fixed direction) is arrange | positioned.

  Here, the orientation magnetic flux density of the residual magnetic flux density of the bonded magnet manufactured by a general method (compression molding, extrusion molding, etc.) is applied at the center of the magnetization direction of the laminate L to be magnetically oriented. The sizes of the yoke 33, the N-type permanent magnet 34 and the S-type permanent magnet 35 constituting the magnetic circuit 32 are appropriately changed in consideration of the size and the material of the laminate L. Here, the applied orientation magnetic flux density is preferably one to two times the residual magnetic flux density of the bonded magnet to be manufactured. By doing this, magnetic anisotropy equivalent to that of a bonded magnet manufactured by a general method can be obtained. For example, the N-type permanent magnet 34 and the S-type permanent magnet 35 are SmCo-based permanent magnets, and the magnetic powder is a Sr-based ferrite, a Ba-based ferrite, a Sr-La-Co-based ferrite, or a Ca-La-Co-based ferrite. When it is a ferrite and the length of the multilayer body L is about 5 mm to 10 mm, the orientation magnetic flux density to be applied to the center of the magnetization direction of the multilayer body L is 0.2 T to 0.5 T.

  The temperature controller 38 includes a heater (not shown), and adjusts the temperature in the heat treatment furnace 31 in a range of, for example, room temperature to about 250 ° C. The temperature may be adjusted to a higher temperature depending on the selected thermoplastic resin.

  Hereinafter, steps of a method of manufacturing an anisotropic bonded magnet according to the present invention will be described. FIG. 4 is a flowchart showing the procedure of the method of manufacturing an anisotropic bonded magnet according to the present invention. In this manufacturing method, a step (S1) of forming a resin molded body R as a material using the forming machine 2 shown in FIG. 2 and a laminate L (e.g. using the laminate forming apparatus 1 shown in FIG. Step (S2) of forming the anisotropic bonded magnet, and a step of placing the formed laminate L in the container 40 and placing the container 40 containing the laminate L in the heat treatment apparatus 3 in the magnetic field shown in FIG. (S3) and the step (S4) of performing heat treatment (orientation treatment) in a magnetic field on the laminate L using the heat treatment apparatus 3 in a magnetic field shown in FIG. 3 and cooling the laminate L subjected to the alignment treatment And (e) obtaining a directionally bonded magnet.

  First, the process of forming the resin molded body R will be described. Through the hopper 26 of the forming machine 2 shown in FIG. 2, the magnetic powder as the material of the resin molded body R and the thermoplastic resin are introduced into the cylinder 25.

  The material of the magnetic substance used as the magnetic powder is, for example, Sr ferrite, Ba ferrite, Sr-La-Co ferrite, Ca-La-Co ferrite, Sm-Fe-N alloy, R-T-B. It is a base alloy. By using these magnetic materials, anisotropic bonded magnets can be manufactured with relatively low magnetic field strength. In the present invention, any type of magnetic material can be used. The magnetic material is ground beforehand to be in the form of powder having an average particle diameter of 3 μm to 5 μm. The average particle size is set to a predetermined range using a laser diffraction type particle size distribution measuring apparatus. Here, in the R-T-B-based alloy, R is a rare earth element and necessarily contains either Nd or Pr, T is a transition metal and necessarily contains Fe, and B is boron.

  On the other hand, as the thermoplastic resin, one having a low melting point and having toughness and impact resistance is used. As a thing which satisfy | fills such conditions, polyamide synthetic fibers, such as nylon, are preferable. Specifically, it is preferable to use 12 nylon, polypropylene, a liquid crystal polymer, polyphenylene sulfide or the like, and 12 nylon (melting point: 179 ° C.) can be used as a representative example. The heat treatment temperature and heat treatment time described in detail below vary depending on the selected thermoplastic resin or combination of thermoplastic resins.

  Magnetic powder and thermoplastic resin (for example, 12 nylon) to be materials are put into the cylinder 25 and the thermoplastic resin is added to the magnetic powder at 200 ° C. to 300 ° C. (preferably 250 ° C. to 270 ° C.) by rotation of the screw 27. The mixture is kneaded and the mixture of the two is extruded to the tip side in the molten state of the thermoplastic resin and supplied to the mold 28 having an inner diameter of 0.1 mm to 1 mm, and the wire-like resin molded body R is extruded from the mold 28. Thereafter, the extruded resin molded body R is cooled and solidified in a water-cooled container (not shown).

  When an orientation coil (not shown) is provided around the mold 28, the mixture is applied with a magnetic field from the orientation coil when passing through the mold 28, and has magnetic anisotropy. A resin molded body R containing magnetic powder is obtained. In such a case, the magnetic flux density of the space of the mold 28 applied to the mixture from the orientation coil is preferably 0.2 T or more. In the method of three-dimensional printing, although only the resin molded body R containing magnetic powder having magnetic anisotropy does not become an anisotropic bonded magnet, it has an effect of shortening the time according to steps S2 to S5 described later.

  Next, the process of shape | molding the laminated body L (isotropic bonded magnet) which makes a desired shape is demonstrated. The resin molded body R formed in the above-described process is introduced into the heater 14 through the heat insulating cylinder 17 by the rotating roller 18 shown in FIG. The heater 14 heats the introduced resin molded body R. The heating temperature at this time is set to a temperature equal to or higher than the melting point of the thermoplastic resin used (preferably 190 ° C. to 220 ° C. when 12 nylon is used for the thermoplastic resin). The heater 14 supplies the mixture in which the thermoplastic resin is melted to the nozzle 15.

  The supplied mixture is extruded from the nozzle 15 while relatively moving the nozzle 15 and the stacking table 13 in three dimensions according to the shape of the laminate L to be molded (anisotropic bond magnet to be manufactured) The stacked body L is formed on the stacking table 13 by sequentially stacking. At this time, the temperature of the stacking table 13 is maintained at 70 ° C. to 110 ° C. The shape of the laminate L may be, for example, a cylindrical shape, a cylindrical shape, a polygonal columnar shape, or a polygonal cylindrical shape, and the barrel has a barrel shape with a central diameter larger than that of the end, and conversely, the central diameter is greater than the end diameter Like small drum shapes, shapes are also possible which can not be easily manufactured by end extrusion alone. In addition, it is possible to use a cylindrical, cylindrical, polygonal columnar or polygonal cylindrical magnet shape for a motor magnet in which the switch driving projection is simultaneously formed on the end portion or the side surface.

  The diameter of the nozzle 15 is about 0.3 mm to 0.7 mm, preferably about 0.4 mm to 0.6 mm, to narrow the lamination pitch. By narrowing the lamination pitch, the density of the molded laminate L can be increased. Specifically, the lamination pitch is preferably about 0.03 mm to 0.3 mm.

  Although not shown, when molding the laminate L as described above, a skirt (a laminate of a resin one size larger than the laminate L) is prepared in advance in a region where the laminate L is formed on the laminate table 13 It is preferable to keep the By preparing the skirt, it is possible to precisely laminate the mixture extruded from the nozzle 15.

  Further, although not shown, a permanent magnet may be provided on the lower surface of the laminate table 13 at the position where the laminate L is formed. The magnetic powder in the mixture in which the thermoplastic resin is molten is attracted to the provided permanent magnet, and the mixture extruded from the nozzle 15 tends to be collected at the center of the stacking table 13 and scattered around. Can be prevented, and laminated molding can be performed efficiently.

  Next, the process of arranging the molded laminate L in the heat treatment apparatus 3 in a magnetic field will be described. The laminate L formed in the above-described process is accommodated in a container 40 which is not thermally deformed. The container 40 is made of, for example, aluminum. The container 40 has a similar shape to the stack L to be accommodated, and is slightly larger than the stack L. Since the container 40 is housed in such a container 40, it is possible to suppress the shape of the laminate L from being broken during the heat treatment in the subsequent magnetic field. The container 40 is preferably made of a nonmagnetic material from the viewpoint that the laminate L can perform desired anisotropic magnetic field alignment accurately without being affected by the magnetic field of the container 40 in the later heat treatment in a magnetic field. Depending on the desired orientation, a container made of a magnetic material such as magnetic stainless steel or a nonmagnetic container in which a magnetic material is partially incorporated may be used.

  In the opposing area between the N-type permanent magnet 34 (the magnetic shunt plate 36) and the S-type permanent magnet 35 (the magnetic shunt plate 37) in the magnetic circuit 32 in the heat treatment furnace 31, the container 40 containing the laminate L is The axial direction is aligned with the vertical direction. Therefore, the container 40 which accommodated the laminated body L is arrange | positioned in the magnetic field area | region which a magnetic flux makes a fixed direction (direction which goes down from the top). The shape of the container 40 is produced according to the shape of the molded laminate L. For example, a barrel-shaped cylindrical laminate L having a central portion larger in diameter than the end portion may be a container which is divided into upper and lower portions at the central portion. In addition, in the case of the laminated body L in the shape of a magnet for motor formed by simultaneously molding the protrusion for switch driving, a concave portion capable of accommodating the protrusion for switch driving is formed in the upper portion. You should do it. Moreover, although the direction of the magnetic flux which can be made to the opposing area | region of a N-type permanent magnet and a S-type permanent magnet is a direction which goes to the bottom from top in FIG. 3, it is not limited to this. Depending on the orientation direction to the laminate L, it may be left or right, or may be oblique. Also, there may be a plurality of combinations of N-type permanent magnets and S-type permanent magnets so that a plurality of poles can be produced.

  Next, a process of subjecting the laminate L to a heat treatment (orientation treatment) in a magnetic field will be described. As described above, after the container 40 containing the formed laminate L is placed in the heat treatment furnace 31, the container 40 containing the laminate L is heated together with the magnetic circuit 32 in the atmosphere. That is, the laminate L is oriented while the heating is performed, in a certain direction. As a result, the multilayer body L becomes a multilayer body L (anisotropic bonded magnet) having anisotropy in which the orientation direction of the magnetic powder is aligned in the vertical direction. Here, since the laminated body L is accommodated in the container 40, it does not deform | transform even if it is heated, and maintains the desired shape.

  The heat treatment temperature at this time is equal to or higher than the melting point of the thermoplastic resin. By melting the thermoplastic resin at the time of orientation, the mobility of the magnetic powder is improved, the magnetic field is easily oriented, and the anisotropic bonded magnet can be efficiently produced. The heat treatment temperature is suitably 190 ° C. to 240 ° C. when using 12 nylon as a thermoplastic resin, 170 ° C. to 210 ° C. for polypropylene, and 240 ° C. to 300 ° C. for liquid crystal polymer and polyphenylene sulfide . These temperatures are maintained for about 0.5 hours to 3 hours. Moreover, as for the magnetic flux density of the space which performs magnetic field orientation, 0.4T-0.9T are preferable. The value of 0.4 T or more is a magnetic flux density which is considered to be necessary to make the ferrite-based magnetic powder have anisotropy.

  Next, the process of cooling the laminated body L which is magnetically oriented will be described. After performing the heat treatment in the magnetic field as described above, the laminate L is cooled together with the container 40 and the magnetic circuit 32 in the heat treatment furnace 31 in the air atmosphere while the magnetic field orientation is continued. After the cooling process, an anisotropic bonded magnet having a desired shape is obtained. After the cooling treatment to below the melting point of the thermoplastic resin, the anisotropic orientation of the manufactured anisotropic bonded magnet is not broken by taking out the container 40 containing the anisotropic bonded magnet.

  The cooling temperature at this time is below the melting point of the thermoplastic resin. When using 12 nylon as a thermoplastic resin, specifically, it cools to 170 degrees C or less, Preferably it cools to 100 degreeC. More preferably, it cools to room temperature. In this case, the magnetic film may be rapidly cooled from 190 ° C. to 240 ° C. during the heat treatment in a magnetic field to room temperature, or may be gradually cooled to 150 ° C., 100 ° C. or the like.

  In the example described above, the atmosphere in the heat treatment furnace 31 is the air, but a vacuum atmosphere or an inert gas atmosphere may be used. However, when using an RTB-based alloy as the magnetic powder, a vacuum atmosphere or an inert gas atmosphere such as nitrogen or argon is preferable. By performing heat treatment in a magnetic field in a vacuum atmosphere, inert gas atmosphere such as nitrogen, argon, etc., the RTB-based alloy is not oxidized during the heat treatment step in the magnetic field, and a difference using the RTB-based alloy The magnetic properties of the directionally bonded magnet are enhanced. It is desirable to carry out in a vacuum higher than 100 Pa, and the pressure is preferably 0.01 Pa to 100 Pa.

  FIG. 5 is a perspective view showing another configuration example of the magnetic circuit 32 in the heat treatment apparatus 3 in a magnetic field. In this example, the rectangular cylindrical yoke 33, the rectangular S-shaped permanent magnet 35 for orientation provided on the lower surface (inner surface) of the upper piece 33a of the yoke 33, and the upper surface of the lower piece 33b of the yoke 33. And an N-type permanent magnet 34 for orientation, which is provided on the (inner surface) and has a rectangular shape. With such a configuration, in the opposing region between the N-type permanent magnet 34 and the S-type permanent magnet 35, magnetic flux in a fixed direction (arrow direction in FIG. 5: direction from bottom to top) as a magnetic anisotropy direction. Flows. A ring-shaped laminate L, which is molded by the laminate molding apparatus 1 and accommodated in a container (not shown), is disposed in the facing region (a magnetic field in a predetermined direction). Then, preferably, an oriented magnetic flux density that is 1 to 2 times the residual magnetic flux density of a bonded magnet manufactured by a general method is applied in the magnetic anisotropy direction (arrow direction in FIG. 5).

  Moreover, FIG. 6 is sectional drawing which shows the other structural example of the heat processing apparatus 3 in a magnetic field. The heat treatment apparatus 3 in the magnetic field has a U-shaped yoke 33, and an N-type permanent magnet 34 for orientation in a rectangular shape is provided on one of the inner surfaces opposed to the yoke 33, and the other inner surface is provided. A rectangular S-shaped permanent magnet 35 for orientation is provided. A magnetic circuit 32 is configured by the yoke 33, the N-type permanent magnet 34 and the S-type permanent magnet 35.

In the opposing region (between the magnetic gaps) between the N-type permanent magnet 34 and the S-type permanent magnet 35 in the yoke 33, a vacuum heat insulation container 42 as a heat insulation means having a heater 41 as heat treatment means inside is installed. ing. In a mode in which the side surface is covered by the heater 41, the columnar laminate L which is formed by the laminate forming apparatus 1 and accommodated in a container (not shown) is disposed. Then, in the orientation residual magnetic flux density to be applied, the orientation magnetic flux density which is preferably 1 to 2 times the residual magnetic flux density of the bonded magnet manufactured by a general method has a magnetic anisotropy direction (arrow direction in FIG. Applied from right to left).

  Although the magnetic circuit 32 is disposed in the heat treatment furnace 31 in the magnetic field heat treatment apparatus 3 shown in FIG. 3, the magnetic field heat treatment apparatus 3 shown in FIG. 6 is a magnetic circuit outside the heat treatment container (vacuum insulation container 42). 32 is arranged. In the configuration example shown in FIG. 6, since the heat treatment container is constituted by the vacuum heat insulation container 42, the heat treatment temperature is hardly influenced, and deterioration of the magnetic circuit 32 due to heat demagnetization can be suppressed. More stable heat treatment is possible. Here, a normal excitation coil may be used as the magnetic circuit 32. The operations such as heat treatment (alignment treatment) in a magnetic field in the heat treatment apparatus 3 in a magnetic field shown in FIG. 6 are the same as in the case of the heat treatment apparatus 3 in a magnetic field shown in FIG.

  In the present invention, as described above, anisotropic bonded magnets of various shapes can be manufactured without manufacturing a mold. In the present invention, if a lamination drawing is created by CAD (Computer Aided Design), the magnetic powder and the melted thermoplastic are relatively moved in three dimensions relative to the nozzle 15 and the lamination base 13 according to the lamination drawing. By extruding and laminating a mixture of resins, the laminate from which the anisotropic bonded magnet is formed can be formed into a desired shape. Therefore, it is possible to easily manufacture an anisotropic bonded magnet having a desired shape even if it is complicated. For example, an anisotropic bonded magnet having a shape in which a part is constricted like a drum shape, or an anisotropic bonded magnet having a protrusion on a cylindrical body can be easily manufactured. Since preparation of a mold requiring a long time is not necessary, it is possible to manufacture an anisotropic bonded magnet in a short time.

  Further, in the present invention, the laminated body (isotropic bonded magnet) whose shape is determined is subjected to heat treatment (orientation treatment) in a magnetic field, so that no disorder of orientation occurs and the magnetic anisotropy is excellent. Anisotropic bonded magnets can be manufactured.

  Various anisotropic bonded magnets were manufactured according to the manufacturing method of the present invention as described above, and the characteristics of the manufactured anisotropic bonded magnet were measured. The results will be described below.

Example 1
A columnar anisotropic bonded magnet was manufactured using Sr ferrite (composition: SrO · 6Fe ₂ O ₃ ) as the magnetic powder and 12 nylon as the thermoplastic resin. The particle size of the magnetic powder used is 3 μm or less at D50, and the ferrite magnetic powder and 12 nylon resin are mixed in the forming machine 2 shown in FIG. 2 and extruded in a molten state and cooled. Bar-shaped resin molded body R was obtained. Thereafter, using the laminate molding apparatus 1 shown in FIG. 1, the obtained resin molded body R is heated to a temperature equal to or higher than the melting point of the thermoplastic resin, and the nozzle 15 and the stacking table 13 are relatively moved in three dimensions. The supplied mixture was extruded from the nozzle 15 and sequentially laminated on a laminating table to form a cylindrical body so as to have a predetermined molding density, to obtain a laminate L. The formed laminate L was housed in a container 40, and heat treatment was carried out in a magnetic field by the heat treatment apparatus 3 in a magnetic field shown in FIG. After heat treatment in a magnetic field, processing with a grindstone was performed to correct the shape, and a cylindrical anisotropic bonded magnet of diameter 10 mm × length 7 mm was manufactured. The magnetic flux density of the space performing the magnetic field orientation in the heat treatment in a magnetic field was 0.4 T, and the temperature of 230 ° C. was maintained for 3 hours in the heat treatment in the magnetic field. It cooled to room temperature (25 degreeC), setting the magnetic flux density of the space which performs magnetic field orientation to 0.4T, and performing magnetic field orientation. The atmosphere of the heat treatment furnace 31 was air. The direction in which the magnetic flux flows in the heat treatment apparatus 3 in the magnetic field is from the top to the bottom.

Various anisotropic bonded magnets are manufactured by changing the volume mixing ratio of the magnetic powder and the thermoplastic resin to be used, and the properties (magnetic flux density in the direction of orientation by heat treatment in a magnetic field ( B _r ), density, coercivity (H _cB ), maximum energy product ((BH) _max ) were measured The measurement results are shown in Table 1. In addition, the magnetic characteristics were measured using a B-H tracer and the density Was measured using the Archimedes method.

  No. 1 to No. 5 in Table 1 represent Example 1 of the present invention in which the volume mixing ratio of the magnetic powder and the thermoplastic resin is different. Moreover, No6 in Table 1 represents the reference example which did not heat-process in a magnetic field.

  Magnetic properties superior to No. 6 were measured for No. 1 to No. 5 in Example 1. When No. 1 to No. 5 in Table 1 are compared, in the case where the ratio of the magnetic powder is large, the magnetic characteristics of the manufactured anisotropic bonded magnet are improved. However, when the proportion of the magnetic powder is increased, the flowability of the mixture is lowered, and the lamination process for obtaining a desired shape becomes difficult. As described above, since the obtained magnetic properties and the ease of manufacture are in a contradictory relationship, the volume mixing ratio of the magnetic powder to the thermoplastic resin is 50: 50 (No. 2) to 56.5: 43.5 (No. 3) It can be said that the range of) is preferable.

  When No. 2 (Example 1) and No. 6 (Reference Example) in Table 1 are compared, No. 6 subjected to no heat treatment in a magnetic field is far inferior in magnetic characteristics to No. 2 subjected to heat treatment in a magnetic field, It can be seen that magnetic orientation can be performed with high accuracy by heat treatment in a magnetic field.

(Comparative example 1)
The anisotropic bonded magnet was manufactured using the extruder described in patent document 2 as a comparative example. As a material, the same one as in Example 1 (particle diameter of magnetic powder: D50 of 3 μm or less, magnetic powder: Sr ferrite (composition: SrO · 6Fe ₂ O ₃ ) and thermoplastic resin: 12 nylon) is used. The volume mixing ratio of the powder and the thermoplastic resin is changed, and the magnetic flux density of the space for performing the magnetic field orientation is 0.4 T, and two types of the same shape (10 mm in diameter × 7 mm in length) as in Example 1 An anisotropic bonded magnet was manufactured. The contents described in Patent Document 2 were applied to the manufacturing conditions. The characteristics of the produced anisotropic bonded magnet were measured in the same manner as in Example 1. The measurement results are shown in Table 2.

When No. 2 and No. 3 in Table 1 are compared with No. 7 and No. 8 in Table 2, in the present invention, an anisotropic bonded magnet having magnetic properties similar to those of an anisotropic bonded magnet manufactured by a conventional extruder is used. It can be seen that it can be manufactured. As for density, No. 2 in Table 1 is lower than No. 7 in Table 2 and No. 3 in Table 1 is lower than No. 8 in Table 2. However, in the present invention, the values of B _r , H _cB and (BH) _max are equivalent to each other. It has become. This is considered to be due to the fact that it is more anisotropically oriented than the anisotropic bonded magnet manufactured by the conventional extruder.

(Example 2)
Sm-Fe-N based alloy as the magnetic powder (composition: Sm ₂ Fe ₁₇ N ₃₎ using, by using the 12 nylon as a thermoplastic resin was prepared by the anisotropic bonded magnet. The shape of the anisotropic bonded magnet in Example 2, the particle diameter of the magnetic powder, the method of forming the resin molded body R, the method of forming the laminate L, the heat treatment method in a magnetic field, and the space for performing magnetic field orientation in heat treatment in a magnetic field The magnetic flux density, the temperature and the holding time, the cooling conditions, and the atmosphere of the heat treatment furnace 31 are the same as those of the first embodiment described above.

  Similar to Example 1, the volume mixing ratio of the magnetic powder and the thermoplastic resin to be used was changed to manufacture various anisotropic bonded magnets, and the characteristics of the anisotropic bonded magnets were measured. The measurement results are shown in Table 3.

  Nos. 9 to 14 in Table 3 represent Example 2 of the present invention in which the volume mixing ratio of the magnetic powder and the thermoplastic resin is different. Further, No. 15 in Table 2 represents a reference example in which the heat treatment in the magnetic field was not performed.

  Also in Example 2, magnetic characteristics superior to No. 15 are measured for all the examples (No. 9 to No. 14). For the same reason as in Example 1, the volume mixing ratio of the magnetic powder to the thermoplastic resin is preferably in the range of 50: 50 (No. 11) to 56.5: 43.5 (No. 12). Further, as in Example 1, No. 15 in which the heat treatment was not performed in the magnetic field was far inferior in magnetic characteristics to No. 11 in which the heat treatment was performed in the magnetic field, and the magnetic orientation could be performed with high accuracy by the heat treatment in the magnetic field. Know that

(Example 3)
In Example 3, the temperature in the cooling process which is the final step of the manufacturing method of the present invention was variously changed to manufacture an anisotropic bonded magnet. Materials of magnetic powder and thermoplastic resin used in Example 3, shape of anisotropic bonded magnet, particle diameter of magnetic powder, method of forming resin molded body R, method of forming laminate L, heat treatment in magnetic field, magnetic field The magnetic flux density, the temperature and the holding time of the space for performing the magnetic field orientation in the middle heat treatment, and the atmosphere of the heat treatment furnace 31 are the same as those in the first embodiment described above. However, as for the cooling conditions, six kinds of anisotropic bonded magnets were manufactured by changing the cooling temperature to 100 ° C., 170 ° C., and 190 ° C. while setting the magnetic flux density in the space for performing magnetic field orientation to 0.4T. . The characteristics of six anisotropic bonded magnets manufactured were measured. The measurement results are shown in Table 4.

  No. 16-No. 18 in Table 4 is an example in which the volume mixing ratio of magnetic powder to thermoplastic resin is 50: 50, and No. 19-No. 21 in Table 4 has a volume mixing ratio of magnetic powder to thermoplastic resin of 56. 5: 43.5 is an example. Moreover, No. 16 and No. 19 in Table 4 are examples cooled to 100 ° C. lower than the melting point (179 ° C.) of 12 nylon used as the thermoplastic resin, and Nos. 17 and 20 in Table 4 were used as the thermoplastic resin It is an example cooled to 170 ° C. lower than the melting point of 12 nylon, and Nos. 18 and 21 in Table 4 are examples cooled only to 190 ° C. higher than the melting point of 12 nylon used as the thermoplastic resin. Therefore, No16, No17, No19 and No20 in Table 4 are examples of the present invention, and No18 and No21 in Table 4 are reference examples.

  According to the results in Table 4, in the reference examples (No. 18 and No. 21) not cooled to below the melting point of 12 nylon used as the thermoplastic resin, the examples of the present invention cooled to below the melting point (No. 16, No. 17, No. 19 and No. 20) The magnetic properties obtained are far inferior to those of. Therefore, it is understood that in the present invention, a process of cooling to below the melting point of the thermoplastic resin is necessary.

(Example 4)
Example 4 is an example in which an anisotropic bonded magnet was manufactured using a material other than 12 nylon as the thermoplastic resin. An anisotropic bonded magnet was manufactured using Ba-based ferrite (composition: BaO · 6Fe ₂ O ₃ ) as the magnetic powder and using polypropylene, a liquid crystal polymer or polyphenylene sulfide as the thermoplastic resin. The shape of the anisotropic bonded magnet in Example 4, the particle diameter of the magnetic powder, the method of forming the resin molded body R, the method of forming the laminate L, the heat treatment method in a magnetic field, and the space for performing magnetic field orientation in heat treatment in a magnetic field The magnetic flux density and the holding time, and the atmosphere of the heat treatment furnace 31 are the same as those of the first embodiment described above. However, the heat treatment temperature was set to 210 ° C. for polypropylene and 330 ° C. for liquid crystal polymer and polyphenylene sulfide, and the cooling condition was cooled to 50 ° C. while setting the magnetic flux density in the space where magnetic orientation was 0.4T.

  The characteristics of the three anisotropic bonded magnets manufactured were measured. The measurement results are shown in Table 5.

  No22, No23, and No24 in Table 5 represent anisotropic bonded magnets when polypropylene, a liquid crystal polymer, and polyphenylene sulfide are used as the thermoplastic resin, respectively. Also in Example 4, excellent magnetic properties are measured for all the examples (No. 22 to No. 24).

(Example 5)
R-T-B type alloy as a magnetic powder _{(composition: Nd 2 (Fe, Nb,} Ga) 14 B) using, by using the 12 nylon as a thermoplastic resin was prepared by the anisotropic bonded magnet. The shape of the anisotropic bonded magnet in Example 5, the particle diameter of the magnetic powder, the method of forming the resin molded body R, the method of forming the laminate L, the heat treatment method in a magnetic field, and the space for performing magnetic field orientation in heat treatment in a magnetic field The magnetic flux density, temperature and holding time, and cooling conditions are the same as in Example 1 above. However, as for the atmosphere of the heat treatment furnace 31, No. 25 to No. 28 are the same as in Example 1 above (in the air), but No. 30 controlled the pressure to 50 Pa and the oxygen content to a vacuum atmosphere of less than 1000 ppm.

  Similar to Example 1, the volume mixing ratio of the magnetic powder and the thermoplastic resin to be used was changed to manufacture various anisotropic bonded magnets, and the characteristics of the anisotropic bonded magnets were measured. The measurement results are shown in Table 6.

  Nos. 25 to 28 in Table 6 represent Example 5 of the present invention in which the volume mixing ratio of the magnetic powder and the thermoplastic resin is different. Further, No. 29 in Table 6 represents a reference example in which the heat treatment in the magnetic field was not performed.

  Also in Example 5, excellent magnetic properties are measured for No25-No28 and No30. Further, for the same reason as in Example 1, the volume mixing ratio of the magnetic powder to the thermoplastic resin is preferably in the range of 50: 50 (No. 25) to 56.5: 43.5 (No. 26, No. 30). Further, as in Example 1, No. 29 in which the heat treatment was not performed in a magnetic field was far inferior in magnetic characteristics to No. 26 in which the heat treatment was performed in a magnetic field, and magnetic field orientation could be performed with high accuracy by heat treatment in a magnetic field. Know that

No. 30 of Example 5 was manufactured under the same conditions as No. 26 except that the atmosphere of the heat treatment furnace 31 was a vacuum. By being in vacuum, the oxidation of the R-T-B-based alloy was suppressed, and B _r , H _cB and (BH) _max were further improved.

(Example 6)
A magnetic powder having a diameter of 10 mm and a length of 7 mm, using a Sm-Fe-N alloy (composition: Sm ₂ Fe ₁₇ N ₃ ) of 3 μm or less at D50 as a magnetic powder and 12 nylon as a thermoplastic resin. An anisotropic bonded magnet was manufactured. The magnetic flux density of the space performing the magnetic field orientation in the heat treatment in the magnetic field is 0.7 T or 0.9 T, and the temperature of 240 ° C. is maintained for 1 hour in the heat treatment in the magnetic field. It cooled to room temperature (25 degreeC), setting the magnetic flux density of the space which performs magnetic field orientation to 0.7 T or 0.9 T, and performing magnetic field orientation. The atmosphere of the heat treatment furnace 31 was air. The particle diameter of the magnetic powder, the method of forming the resin molded body R, the method of forming the laminate L, and the method of heat treatment in a magnetic field are the same as in Example 1 above.

  Various anisotropic bonded magnets are manufactured by changing the volume mixing ratio of magnetic powder and thermoplastic resin to be used or the magnetic flux density of the space for performing magnetic field orientation in heat treatment in a magnetic field, and the characteristics of those anisotropic bonded magnets Was measured. The measurement results are shown in Table 7.

  No. 31 and No. 32 in Table 7 represent Example 6 of the present invention in which the volume mixing ratio of the magnetic powder and the thermoplastic resin is different. No. 31 and No. 33 in Table 7 represent Example 6 of the present invention in which the magnetic flux density of the space performing the magnetic field orientation in the heat treatment in the magnetic field is different at 0.7 T and 0.9 T.

  When No31 and No32 of Example 6 are compared, in the example (No 32) with many ratios of magnetic powder, the magnetic characteristic of the manufactured anisotropic bonded magnet is improving. Even in the sixth embodiment, the volume mixing ratio of the magnetic powder to the thermoplastic resin is 50: 50 (No. 31) to 56.5: 43.5 (No. 32) for the same reason as the above-mentioned first embodiment. Is preferable. When No. 31 and No. 33 in Example 6 are compared, in the example (No. 33) in which the magnetic flux density in the space for performing magnetic field orientation in the heat treatment in a magnetic field is high (No. 33), the magnetic properties of the manufactured anisotropic bonded magnet are improved. It can be said that the magnetic flux density in the space where the magnetic field orientation is performed in the heat treatment in a magnetic field is preferably high.

(Comparative example 2)
The anisotropic bonded magnet was manufactured using the extruder described in patent document 2 as a comparative example. As a material, the same one as in Example 6 (magnetic powder: Sm-Fe-N alloy (composition: Sm ₂ Fe ₁₇ N ₃ ) D50 3 μm or less and thermoplastic resin: 12 nylon) is used, Example 6 An anisotropic bonded magnet of the same shape (cylindrical body 10 mm in diameter × 7 mm in length) as in the above was manufactured. The contents described in Patent Document 2 were applied to the manufacturing conditions. Specifically, a mixture of the anisotropic magnetic powder and the resin was extrusion molded while applying a magnetic flux density of 0.9 T using an extruder having a coil for applying a magnetic field at the extrusion port. The characteristics of the produced anisotropic bonded magnet were measured in the same manner as in Example 6. The measurement results are shown in Table 8.

When No. 31 and No. 33 in Table 7 and No. 34 in Table 8 are compared, in the present invention, an anisotropic bonded magnet having magnetic properties similar to those of an anisotropic bonded magnet manufactured by a conventional extruder can be manufactured. Know that In terms of density, No. 31 and No. 33 in Table 7 are lower than No. 34 in Table 8, but in the present invention, No. 31 in Table 7 is lower in magnetic flux density in the space where magnetic field orientation is performed in heat treatment in a magnetic field _Therefore , although B _r and H _cB have slightly low values, the value of (BH) _max is a better value. Further, No. 33 in Table 7 is equivalent to B _r and H _cB , and the value of (BH) _max is a superior value. The values of B _r and H _cB are equal to each other, and the value of (BH) _max is a superior value. This is considered to be due to the fact that it is more anisotropically oriented than the anisotropic bonded magnet manufactured by the conventional extruder. Further, it is presumed that the time during which the magnetic field is applied is also related to the reason that the value of (BH) _max representing the squareness is better than that of the extruder. Since the extrusion molding machine performs molding continuously, it is near the extrusion port that a magnetic field is applied, but in the present invention, the orientation is improved because the magnetic field is continuously applied during heat treatment to be oriented. It is estimated that the squareness has improved.

  From the measurement results of the anisotropic bonded magnet in Example 1-6 described above, it can be proved that the present invention can manufacture an anisotropic bonded magnet having excellent magnetic properties.

  It should be understood that the disclosed embodiments are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

DESCRIPTION OF SYMBOLS 1 Laminated body formation apparatus 2 Forming machine 3 Heat treatment apparatus in magnetic field 13 Lamination table 15 Nozzle 19 Guide 20 Belt 21 Pedestal 22 Pedestal 23 Guide 24 Ball screw 31 Heat treatment furnace 32 Magnetic circuit 40 Container
41 Heater (heat treatment means)
42 Vacuum insulation container (insulation method)
L stack

Claims (5)

In a method of manufacturing an anisotropic bonded magnet,
Forming a laminate by extruding and laminating a mixture of magnetic powder and molten thermoplastic resin from a nozzle to a laminating table while relatively moving the nozzle and the laminating table in three dimensions;
Placing a container containing the molded laminate in a magnetic field region in a predetermined direction;
Orienting a magnetic field in a certain direction on the laminate in the container while maintaining a temperature above the melting point of the thermoplastic resin;
While orienting the magnetic field of the predetermined direction and have a a step of cooling the laminate to a temperature below the melting point of the thermoplastic resin,
The volume mixing ratio between the magnetic powder and the thermoplastic resin is in the range of 50:50 to 56.5: 43.5 .   The method for producing an anisotropic bonded magnet according to claim 1, wherein the magnetic powder in the mixture has magnetic anisotropy. The material of the magnetic substance used as the magnetic powder is Sr ferrite, Ba ferrite, Sr-La-Co ferrite, Ca-La-Co ferrite, Sm-Fe-N alloy, and RTB. It is selected from the group consisting of a system alloy (R is a rare earth element and must contain either Nd or Pr. T is a transition metal and must contain Fe. B is boron.) The manufacturing method of the anisotropic bonded magnet of Claim 1 or 2 characterized by these. In a system for manufacturing anisotropic bonded magnets,
A nozzle for extruding a mixture of magnetic powder and a melted thermoplastic resin, a lamination table for receiving and laminating the mixture extruded from the nozzle, and relatively moving the nozzle and the lamination table in three dimensions A forming mechanism for forming a laminate by laminating the mixture on the laminating table while moving the nozzle and the laminating table relatively in three dimensions;
A magnetic circuit for forming a magnetic field in a fixed direction, and a heat treatment furnace which accommodates the magnetic circuit and whose internal temperature can be adjusted, and in the heat treatment furnace, a temperature above the melting point of the thermoplastic resin Orienting the magnetic field in the predetermined direction in the laminate housed in the container while maintaining the pressure in the container, and then orienting the magnetic field in the predetermined direction in the laminate while the laminate is below the melting point of the thermoplastic resin includes a magnetic field in a heat treatment device for cooling to the temperature,
The volume mixing ratio of the magnetic powder to the thermoplastic resin is in the range of 50: 50 to 56.5: 43.5 . In a system for manufacturing anisotropic bonded magnets,
A nozzle for extruding a mixture of magnetic powder and a melted thermoplastic resin, a lamination table for receiving and laminating the mixture extruded from the nozzle, and relatively moving the nozzle and the lamination table in three dimensions A forming mechanism for forming a laminate by laminating the mixture on the laminating table while moving the nozzle and the laminating table relatively in three dimensions;
A magnetic circuit for forming a magnetic field in a fixed direction between magnetic gaps, and a heat treatment means provided in the magnetic gap and capable of controlling the temperature in the magnetic gap; The laminate is subjected to the melting point of the thermoplastic resin while the magnetic field in the specific direction is oriented in the laminate while maintaining the temperature at a temperature equal to or higher than the melting point of the resin. Equipped with a heat treatment device in a magnetic field that cools to a temperature below
The system for manufacturing an anisotropic bonded magnet according to claim 1, wherein the magnetic gap is constituted by a pair of opposing magnets, and a heat insulating means is provided between the magnet and the heat treatment means .

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