JP2018182123A - Molding die for anisotropic magnet and manufacturing method of anisotropic magnet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust a surface flux density waveform into a desired waveform shape by applying a strong orientation field to each magnetic pole of an anisotropic magnet that should be molded, even without disposing a permanent magnet insides and only with a field acting from the outside of a die.SOLUTION: A molding die 1 for an anisotropic magnet comprises a die frame material 2 partitioning a cavity part 3 that can be filled with a composition Cm containing a material of the anisotropic magnet which should be molded, and capable of disposing the cavity part 3 in a field acting from the outside. The die frame material 2 includes: field generation frame materials 4 which are disposed oppositely in such a manner that the cavity part 3 is held therebetween, and consist of a magnetic substance generating a field in a direction across the cavity part 3; and orientation control frame material 5 which is provided in a portion of at least any one of the field generation frame materials 4 holding the cavity part 3 therebetween, facing the cavity part 3 and consists of a non-magnetic substance or a magnetic substance of which saturation magnetization is smaller than the field generation frame materials 4, for controlling an orientation field H determining a direction of magnetization in such a manner that a surface flux density waveform of the anisotropic magnet becomes a desired waveform shape.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mold for forming an anisotropic magnet, and in particular, a mold for forming an anisotropic magnet, which is disposed in a magnetic field acting from the outside to form the anisotropic magnet, and a mold using the same. The present invention relates to a method of manufacturing a anisotropic magnet.

As molds for forming anisotropic magnets, there are an external magnetic field method utilizing a magnetic field generated by a coil provided in a molding machine, a method in which an electromagnet is embedded in the mold, and a method in which a permanent magnet is embedded in the mold. is there.
The orientation of the magnet produced by the external magnetic field type mold is unidirectional, and in the case of a cylindrical magnet, there are an axial direction, a radial direction, a radial direction and the like. The oriented magnet can be used with multiple poles magnetized in the magnetizing step in the post process, but waveform control of the magnet is difficult and cogging occurs when used in a motor etc., causing vibration and heat generation. On the other hand, in the molding die of the external magnetic field type, since the permanent magnet is not built in the mold, demagnetization of the anisotropic magnet molded by adjusting the external magnetic field is easy, and the molded anisotropic is The magnetic force of the magnetic magnet can be reduced.

As an anisotropic magnet configuration for reducing the cogging, there is already known an art of polar anisotropy in which a surface magnetic flux density waveform of a shaped anisotropic magnet is made sinusoidal.
As a mold for molding a polar-anisotropic cylindrical magnet, for example, as shown in Patent Document 1, there are an electromagnet type and a permanent magnet type.
In Patent Document 1, it is pointed out that in the method using an electromagnet, it is difficult to take many pieces because the volume required for the configuration per cavity is large.
On the other hand, while a molding die using a permanent magnet can make the die relatively compact and can be taken out in large numbers, it is a rare earth magnet material which has a low in-cavity magnetic field and in particular requires a large magnetic field for orientation. It is pointed out that molding using the above can not obtain a magnetic field sufficient for orientation.
As a means for solving this and improving the magnetic characteristics of the molded magnet, permanent magnet pieces and N or S magnetic poles are on the cavity surface in each sector-shaped region divided into multiple along the outer periphery of the cylindrical cavity An anisotropic magnet mold is disclosed, in which the back yokes of ferromagnetic material are disposed close to each other in opposite directions and in opposite polarities with respect to each other in each region, and at the outer periphery of the permanent magnet.

  Further, as an external magnetic field system, as shown in, for example, Patent Document 2, a filling step of filling magnet powder in a ring-shaped cavity, and application of a repulsive magnetic field to each other in a predetermined area of the cavity An in-magnetic-field molding method is known which comprises: an in-magnetic-field molding step of orienting in a direction and press-molding the oriented magnet powder to obtain a molded body.

JP-A-5-144649 (Detailed Description of the Invention, FIG. 1) JP-A-2006-19385 (Best mode for carrying out the invention, FIG. 1)

  In Patent Document 1, when magnet molding is performed with a molding die using a permanent magnet, it is necessary to process the orientation magnet into a complicated shape and to arrange the magnets having strong magnetic force side by side, and create a cavity portion. Because of this, expensive alignment magnet materials and a long preparation period are required, leading to an increase in the cost of the mold. In addition, it is very difficult to correct the orientation magnet or the like in order to adjust the surface magnetic flux density waveform of the magnet to be molded, and it is necessary to recreate the cavity from the beginning. Further, the molded magnet is magnetized by the alignment magnet, and since it is adsorbed to the cavity, a strong force is required for the protrusion of the molded product, and it is difficult to take out the molded product. Furthermore, there is a concern that the molded articles taken out may be broken or chipped due to adsorption and repulsion on one another.

  The technical problem to be solved by the present invention is to form each anisotropic magnet to be formed only by the magnetic field acting from the outside of the mold without arranging the permanent magnet inside when forming the anisotropic magnet. A strong orienting magnetic field is given to the magnetic pole to provide a molding die capable of adjusting the surface magnetic flux density waveform to a desired waveform shape, and further, a method of manufacturing an anisotropic magnet using this molding die It is to provide.

  The first technical feature of the present invention is a gold which defines a cavity which can be filled with a composition containing a material of an anisotropic magnet to be molded, and which can arrange the cavity in an externally acting magnetic field. A magnetic field generation frame member comprising a mold material, the mold member being disposed opposite to sandwich the hollow portion, the magnetic field generation frame member comprising a magnetic material generating a magnetic field in a direction crossing the hollow portion, and the hollow portion Orientation that determines the direction of magnetization so that the surface magnetic flux density waveform of the anisotropic magnet to be formed has a desired waveform shape, provided at a portion facing at least one of the hollow portions of the magnetic field generating frame material sandwiching It is a metal mold | die for formation of the anisotropic magnet characterized by having the orientation control frame material which consists of a nonmagnetic material which controls a magnetic field, or a magnetic material whose saturation magnetization is smaller than said magnetic field production | generation frame material.

According to a second technical feature of the present invention, in the mold for forming an anisotropic magnet provided with the first technical feature, the orientation control frame member is formed of magnetic pole intervals of the anisotropic magnet to be formed and the like. It is a mold for forming an anisotropic magnet characterized by having a thin-walled portion whose thickness changes in the same cycle.
According to a third technical feature of the present invention, in the mold for forming an anisotropic magnet provided with the second technical feature, the orientation control frame member is formed of the magnetic pole intervals of the anisotropic magnet to be formed and the like. It is a mold for forming an anisotropic magnet characterized in that it has asperities in which the thickness changes smoothly in the same cycle.
According to a fourth technical feature of the present invention, in the mold for forming an anisotropic magnet having the first technical feature, the magnetic pole side of the anisotropic magnet to be formed in the hollow portion and the orientation control A mold for forming an anisotropic magnet, comprising: a partition member for partitioning the frame member.
According to a fifth technical feature of the present invention, in the mold for forming an anisotropic magnet having the first technical feature, the mold frame material defines an annular or arc-like cavity, and from the outside A mold for forming an anisotropic magnet, characterized in that an acting magnetic field acts in a direction radially crossing the cavity.
According to a sixth technical feature of the present invention, in the mold for forming an anisotropic magnet having the fifth technical feature, the orientation control frame member is disposed on the outer circumferential side of the annular or arc-like cavity. And forming a magnetic pole of an anisotropic magnet to be formed on the inner peripheral side or the outer peripheral side in the hollow portion.
According to a seventh technical feature of the present invention, in the mold for forming an anisotropic magnet having the fifth technical feature, the orientation control frame material is provided on the inner circumferential side of the annular or arc-like cavity. A mold for forming an anisotropic magnet, which is disposed and has a magnetic pole of an anisotropic magnet to be formed on the inner peripheral side or the outer peripheral side in the hollow portion.
According to an eighth technical feature of the present invention, in the mold for forming an anisotropic magnet having the fifth technical feature, the orientation control frame member is provided on the outer peripheral side and inside of the annular or arc-like cavity. Each alignment control frame member is disposed on the circumferential side, and one alignment control frame member has a focusing portion in which magnetic flux is concentrated at a portion corresponding to the magnetic pole of the anisotropic magnet to be formed in the hollow portion. It is a mold for forming an anisotropic magnet, characterized in that the focusing portion is provided at a portion corresponding to a space between magnetic poles.

According to a ninth technical feature of the present invention, in manufacturing an anisotropic magnet using a mold for molding an anisotropic magnet having any one of the first to eighth technical features, the molding method according to the present invention A filling step of filling a composition containing an anisotropic magnet material to be formed in a cavity of a mold, and filling the cavity by applying an external magnetic field to the forming die after the filling step Orientation / forming step of magnetically orienting the formed composition and forming it into a predetermined shape, and a removal step of cooling the anisotropic magnet formed in the orientation / forming step and removing it from the forming mold And a method of manufacturing an anisotropic magnet.
According to a tenth technical feature of the present invention, in the method of manufacturing an anisotropic magnet having the ninth technical feature, in the taking-out step, the magnetic field during the orientation and molding step is reversed in the molding die. It is a method of manufacturing an anisotropic magnet, characterized in that it is carried out by applying an applied magnetic field.

According to the first technical feature of the present invention, when forming an anisotropic magnet, it is possible to form an anisotropic magnet that should be formed only by a magnetic field acting from the outside of the mold without arranging the permanent magnet inside. A strong orienting magnetic field can be given to each magnetic pole, and a molding die capable of adjusting the surface magnetic flux density waveform to a desired waveform shape can be provided.
According to the second technical feature of the present invention, the control action of the orientation magnetic field by the orientation control frame material can be realized easily.
According to the third technical feature of the present invention, by devising the cross-sectional shape of the orientation control frame material, the control action of the orientation magnetic field can be realized while being smoothly changed.
According to the fourth technical feature of the present invention, the appearance of the molded anisotropic magnet can be kept good and the molded product can be easily taken out of the mold, as compared with the embodiment in which the partition member is not used.
According to the fifth technical feature of the present invention, when forming an annular or arc-shaped anisotropic magnet, it is possible to use an anisotropic magnet only with a magnetic field acting from the outside without arranging a permanent magnet inside. On the other hand, it is possible to provide a molding die capable of adjusting the surface magnetic flux density waveform to a desired waveform shape with a strong orientation magnetic field.
According to the sixth technical feature of the present invention, by designing a mold frame material on the outer peripheral side of the existing molding mold, the annular or arc-shaped anisotropic magnet is oriented and molded with high accuracy. can do.
According to the seventh technical feature of the present invention, the annular magnet or circular arc anisotropic magnet can be oriented with high accuracy by devising a mold frame material on the inner peripheral side of the existing molding mold. It can be molded.
According to the eighth technical feature of the present invention, compared to the aspect in which the orientation control frame material is disposed on one of the inner peripheral side or the outer peripheral side of the annular or circular hollow portion, the anisotropic magnet to be formed is The orientation field to the magnetic pole can be finely controlled.
According to the ninth technical feature of the present invention, the magnetic field is applied from the outside by using a molding die capable of adjusting the surface magnetic flux density waveform to a desired waveform shape with a strong orientation magnetic field to the anisotropic magnet. High quality anisotropic magnet with high magnetic force can be easily manufactured.
According to the tenth technical feature of the present invention, compared with the embodiment not having the present configuration, the operation force at the time of the operation of taking out the anisotropic magnet molded from the molding die can be reduced.

(A) is an explanatory view showing an outline of an embodiment of a mold for molding an anisotropic magnet to which the present invention is applied, (b) is an enlarged explanatory view of a region shown by B in (a), (c) FIG. 2 is an explanatory view showing a method of manufacturing an anisotropic magnet using a molding die shown in (a). (A) is explanatory drawing which shows the manufacturing apparatus of the anisotropic magnet which concerns on Embodiment 1, (b) is explanatory drawing which shows an example of the external magnetic field which acts on a metal mold | die in a shaping | molding / orientation process, (c) is taken out. It is explanatory drawing which shows an example of the external magnetic field which acts on a metal mold | die by a process. (A) is explanatory drawing which shows the whole structure of the molding die based on Embodiment 1 seen from the direction cut | disconnected by the III-III line in FIG. 2 (a), (b) is shown by B in (a) FIG. 3C is an enlarged explanatory view corresponding to FIG. 3B in the comparison mode. (A) is explanatory drawing which shows an example of the orientation magnetic field with respect to the composition with which the said shaping die was filled when making an external magnetic field act on the shaping die which concerns on Embodiment 1, (b) is a comparison. It is explanatory drawing which shows an example of the orientation magnetic field with respect to the composition with which the shaping mold which concerns on a form was filled. (A) is explanatory drawing which shows an example of the magnetic hysteresis characteristic of a magnetic field production frame material as a metal mold frame material used in Embodiment 1, and the anisotropic magnet which should be shape | molded, (b) is for shaping at the time of taking-out process. It is explanatory drawing which shows an example of the external magnetic field which acts on a metal mold | die. (A) is explanatory drawing which shows the principal part of the deformation | transformation form of the shaping | molding die of the anisotropic magnet which concerns on Embodiment 1, (b) is an expansion explanatory drawing of the area | region shown by B in (a). (A) is explanatory drawing which shows the principal part of the metal mold | die for shaping | molding of the anisotropic magnet which concerns on Embodiment 2, (b) is an expansion explanatory drawing of the area | region shown by B in (a). (A) is explanatory drawing which shows the principal part of the metal mold | die for shaping | molding of the anisotropic magnet which concerns on Embodiment 3, (b) is an expansion explanatory drawing of the area | region shown by B in (a). (A) is explanatory drawing which shows the principal part of the metal mold | die for shaping | molding of the anisotropic magnet which concerns on Embodiment 4, (b) is an expansion explanatory drawing of the area | region shown by B in (a). (A) is an explanatory view showing a simulation result example of surface magnetic flux density distribution after magnetization of the anisotropic magnet molded in Example 1, (b) is a surface magnetic flux density waveform after magnetization of the same magnet It is an explanatory view showing an example. FIG. 13 is an explanatory view showing an example of a surface magnetic flux density waveform after magnetization of an anisotropic magnet molded in Example 2. (A) is explanatory drawing which shows an example of the surface magnetic flux density waveform after magnetization of the anisotropic magnet shape | molded in Example 3, (b) is a surface magnetic flux density waveform shown to (a), and a sine waveform It is explanatory drawing which shows contrast of. (A) is explanatory drawing which shows an example of the shaping | molding die of the anisotropic magnet which concerns on the comparative example 1, (b) is a surface magnetic flux density waveform after magnetization of the anisotropic magnet shape | molded by the comparative example 1. It is explanatory drawing which shows an example. FIG. 13 is an explanatory view showing an example of a surface magnetic flux density waveform after magnetization of an anisotropic magnet formed in Comparative Example 2;

Outline of Embodiment FIG. 1 (a) (b) shows an outline of an embodiment of a mold for forming an anisotropic magnet to which the present invention is applied.
In the same figure, the mold 1 for molding an anisotropic magnet defines a cavity 3 which can be filled with the composition Cm containing the material of the anisotropic magnet to be molded, and the cavity is applied during an external magnetic field. The mold frame member 2 is provided with a mold frame member 2 capable of arranging 3, and the mold frame member 2 is disposed to face the hollow portion 3 so as to sandwich the hollow portion 3, and a magnetic field made of a magnetic material generating a magnetic field in a direction crossing the hollow portion 3. It is provided at a portion facing the cavity 3 of at least one of the generation frame 4 (specifically 4a, 4b) and the magnetic field generation frame 4 sandwiching the cavity 3 (for example, 4b) Orientation control frame consisting of a nonmagnetic material that controls the orientation magnetic field H that determines the direction of magnetization so that the surface magnetic flux density waveform of the anisotropic magnet has a desired waveform shape or a magnetic material whose saturation magnetization is smaller than the magnetic field generation frame 4 And the material 5.

In such technical means, the anisotropic magnet widely includes anisotropic bonded magnets as long as the anisotropic magnet material is used as a molding material.
Moreover, the metal mold frame material 2 should just divide the cavity part 3 corresponding to the shape of the anisotropic magnet which should be shape | molded, As the cavity part 3, annular shape, a column shape, linear plate shape, etc. are selected suitably It does not matter. Here, as the mold frame material 2, for example, when the anisotropic magnet is annular, an inner frame material and an outer frame material that partition the annular cavity 3 from the inside and the outside are used. Even in the case of so-called insert molding or molding called integral molding, in which another part is inserted into a mold for molding, it widely includes those which define the cavity 3.

Furthermore, the metal mold frame material 2 may include the magnetic field generation frame material 4 and the orientation control frame material 5.
In this example, the magnetic field generation frame member 4 is made of a magnetic material disposed opposite to each other with the hollow portion 3 interposed therebetween, and when the magnetic field is applied from the outside, it is magnetized to generate a magnetic field crossing the hollow portion 3. It only needs to have a function to generate.
The orientation control frame member 5 is preferably a nonmagnetic material, but even if it is not a nonmagnetic material, even a magnetic material such as ELMAX (registered trademark) whose saturation magnetization is smaller than that of the magnetic material forming the magnetic field generation frame 4 It is configurable.
In this example, the orientation control frame member 5 may be provided in at least one of the magnetic field generation frame members 4 sandwiching the cavity 3, but the surface magnetic flux density waveform of the anisotropic magnet to be formed in the cavity 3 is It is necessary to have a function of controlling the orientation magnetic field H which determines the direction of magnetization so as to obtain a desired waveform shape. At this time, in a mode in which the orientation control frame member 5 is provided on one side, it may be provided on the side facing the magnetic pole Mp of the anisotropic magnet or may be provided on the side not facing the magnetic pole Mp. It is necessary to form a desired orientation magnetic field H by controlling the density of the magnetic flux corresponding to the magnetic pole Mp.
Here, with regard to the orientation control frame 5, the thickness of the orientation control frame 5 is periodically changed, and magnetic flux is generated utilizing the fact that the thin portion is more likely to transmit the magnetic field than the thick portion. Although a mode of controlling the density of the magnetic flux corresponding to the magnetic pole Mp of the anisotropic magnet to be formed is representative as the focusing portion 6 to be concentrated, the invention is not limited thereto. For example, among the plate-like orientation control frame members 5 The openings may be formed in the same cycle as the magnetic poles Mp of the anisotropic magnet, and the openings may be used as the focusing portion 6 where magnetic flux is concentrated.

  As described above, in the present example, a magnetic field is generated from the outside to generate a magnetic field in the cavity 3 by the magnetic field generation frame 4, and further, the orientation magnetic field H to each magnetic pole Mp is generated by the orientation control frame 5. A strong orientation magnetic field H is applied to each magnetic pole Mp of the magnet to be molded, and a surface magnetic flux density waveform of the magnet to be molded has a desired waveform shape (for example, a sine wave) at the time of magnetization after molding Desired orientation characteristics can be given to the composition Cm which is a molding material so as to be formed into a waveform approximate to the shape.

Next, a representative aspect or a preferable aspect of the mold for forming an anisotropic magnet according to the present embodiment will be described.
First, as a typical aspect of the orientation control frame member 5, an aspect having a thin-walled part whose thickness changes in the same cycle as the interval between the magnetic poles Mp of the anisotropic magnet to be formed is mentioned. In this example, the thickness of the orientation control frame member 5 is periodically changed to concentrate the magnetic flux in the thin-walled portion 7, whereby the orientation magnetic field H for each magnetic pole Mp can be controlled.
Here, as a preferable embodiment of the orientation control frame member 5, an embodiment having an unevenness in which the thickness changes smoothly in the same cycle as the interval between the magnetic poles Mp of the anisotropic magnet to be formed may be mentioned. In this example, the thickness of the orientation control frame member 5 has unevenness smoothly, and the concave portion is a thin portion 7, the convex portion is a thick portion 8, and the changing portion between the concave portion and the convex portion is smooth. This is effective in forming the surface magnetic flux density waveform of the anisotropic magnet to be formed into a smooth waveform shape that changes periodically.

  Further, as a preferred embodiment of the molding die 1, there may be mentioned an embodiment including a partition member 9 for partitioning between the magnetic pole Mp side of the anisotropic magnet to be molded in the cavity 3 and the orientation control frame member 5. In the present embodiment, the partition member 9 partitions the composition Cm in the hollow portion 3 and the orientation control frame member 5. When such a partition member 9 is used, the composition Cm is not in direct contact with the orientation control frame 5. Therefore, even if, for example, a step is generated between the converging portion 6 of the orientation control frame 5 and other portions, The molded magnet can be easily removed without losing the appearance of the molded magnet. The partition member 9 may be either a magnetic material or a nonmagnetic material.

Furthermore, in a mode of forming an annular or arc-shaped anisotropic magnet, the mold frame member 2 defines the annular or arc-shaped cavity 3, and a magnetic field acting from the outside radially with respect to the cavity 3. The aspect which works from the cross direction is typical.
As a typical aspect of the orientation control frame member 5 in such a molding die 1, the orientation control frame member 5 is disposed on the outer peripheral side of the annular or arc-shaped hollow portion 3, and is molded on the inner peripheral side or the outer peripheral side in the hollow portion 3. The aspect which forms the magnetic pole Mp of the anisotropic magnet which should be mentioned is mentioned. In this example, the orientation control frame member 5 is disposed on the outer peripheral side of the annular or arc-shaped cavity 3 to control the orientation magnetic field H with respect to the magnetic pole Mp of the anisotropic magnet to be formed.
In addition, as another typical aspect of the orientation control frame member 5, it is disposed on the inner peripheral side of the annular or arc-shaped hollow portion 3, and an anisotropy to be formed on the inner peripheral side or outer peripheral side in the hollow portion 3. Of forming the magnetic pole Mp of the magnetic magnet. In this example, the orientation control frame member 5 is disposed on the inner peripheral side of the annular or arc-shaped cavity 3 to control the orientation magnetic field H with respect to the magnetic pole Mp of the anisotropic magnet to be formed.
Furthermore, as another representative embodiment of the orientation control frame member 5, the orientation control frame member 5 is disposed on the outer circumferential side and the inner circumferential side of the annular or arc-shaped cavity 3, and one orientation control frame member 5 is A focusing portion 6 where magnetic flux is concentrated at a portion corresponding to the magnetic pole Mp of the anisotropic magnet to be formed in the hollow portion 3 is provided, and the other orientation control frame member 5 is located at a portion corresponding to the space between the magnetic poles Mp. The aspect which has is mentioned. In this example, the orientation control frame members 5 are disposed on the inner and outer circumferential sides of the annular or arc-shaped cavity 3 respectively, and the magnetic poles Mp of the anisotropic magnet to be formed by both orientation control frame members 5 are provided. The orientation magnetic field H is controlled.

In addition, as a typical embodiment of a manufacturing method of manufacturing an anisotropic magnet using the above-described molding die 1, as shown in FIG. 1 (c), molding is carried out in the hollow portion 3 of the molding die 1. The composition Cm filled in the cavity 3 by externally applying a magnetic field H ₁ to the molding die 1 after the filling step of filling the composition Cm containing the material of the anisotropic magnet to be filled and the filling step after the filling step An embodiment including an orientation and molding process for magnetically orienting and molding into a predetermined shape, and a removal process for cooling the anisotropic magnet molded in the orientation and molding process and taking it out of the molding die 1 It can be mentioned.
This embodiment may be any one having a filling step of molding material, an orientation / molding step and a removal step, and the orientation / molding step includes injection molding, extrusion molding and the like.
Further, as a preferred embodiment of the method for producing an anisotropic magnet, the taking-out step is carried out by applying the magnetic field H _{2 in} which the magnetic field H ₁ is reversed at the time of orientation and molding to the molding die 1. It can be mentioned. In this example, when taking out an anisotropic magnet (molded product) molded from the molding die 1, the magnetized state of the magnetic field generation frame member 4 is demagnetized by acting the reversal magnetic field H ₂ from the outside. The magnetic force of the molded product is demagnetized to suppress the magnetic force that hinders the removal of the molded product.

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the attached drawings.
実 施 Embodiment 1
-Manufacturing equipment of anisotropic magnet-
FIG. 2 shows the entire configuration of the anisotropic magnet manufacturing apparatus according to the first embodiment.
In the same figure, the anisotropic magnet manufacturing apparatus is an injection molding machine for manufacturing an anisotropic magnet by injection molding, and a molding die for molding the anisotropic magnet (hereinafter abbreviated as a mold) 30 and an injection unit 20 for injecting and injecting a composition Cm containing a material of an anisotropic magnet into the mold 30, and an external that applies an external magnetic field to the composition Cm injected and injected into the mold 30 And a magnetic field device 50.
In this example, the anisotropic magnet is a bonded magnet, and as a material of the magnet, ferrite, Sm-Co, Sm-Fe-N, Nd-Fe-B, etc. and / or a mixture thereof Although it is possible to select appropriately from the system, it is necessary to pay attention to the saturation magnetization of each material. That is, for example, even if a magnet molded with a ferrite-based material has a desired surface magnetic flux density waveform, magnets molded with a Sm-Fe-N-based material in the same mold may have different surface magnetic flux density waveforms. In this example, one or more kinds of rare earth anisotropic magnet powder such as anisotropic Sm-Fe-N fine powder and anisotropic Nd-Fe-B fine powder are used as the composition Cm containing the material of the magnet It is assumed that a mixture with a thermoplastic resin is used.
<Ejection unit>
In this example, the injection unit 20 supplies the composition Cm containing the material of the magnet from the hopper 22 into the cylinder 21 and heats and melts the composition Cm introduced into the cylinder 21 with the heater 23, and the cylinder 21 After a predetermined amount of the composition Cm melted by the internally retractable screw rod 24 is stored in the injection port 25 side of the cylinder 21, the composition Cm is injected into the mold 30.

<Mold>
In this example, as shown in FIGS. 2 (a) and 3 (a), the mold 30 has a cavity corresponding to the shape of the anisotropic magnet to be formed in the mold frame member 40 (in this example, An annular cavity 41) is secured.
Here, a connection unit 31 connectable to the injection unit 20 is attached to the injection molding machine by the fixed side attachment plate 32 at a site opposed to the installation location of the mold 30, and communicates with the injection port 25 of the injection unit 20 It has a supply path 26 leading to the cavity 41.
Further, the mold 30 is attached to the movable side mounting plate 34 which can be advanced and retracted in the arrow direction by a mold clamping unit (not shown), and the mold 30 contacts and separates from the connection unit 31 by advancing and retracting the mold clamping unit. It is aligned by an alignment mechanism (not shown). In the present example, the interface between the mold 30 and the connection unit 31 functions as a mold separation surface PL.

Further, the mold 30 is configured by attaching the mold frame member 40 to the movable side mold plate 35 fixed to the movable side mounting plate 34. In the present embodiment, the mold frame member 40 includes a cylindrical inner frame member 42 made of a magnetic material that divides the inside of the annular cavity 41 and an outer frame made of a magnetic material that divides the outer side of the annular cavity 41. An annular sleeve 44 as a partition member made of, for example, a nonmagnetic material, provided between the material 43 and the annular cavity 41 and the outer frame material 43 and partitioning the outer peripheral portion of the annular cavity 41; An orientation control frame member 45 made of a nonmagnetic material provided between the sleeve 44 and the outer frame member 43 and controlling the orientation magnetic field H acting on the composition Cm filled in the annular cavity 41; ing.
Here, the magnetic material constituting the inner frame member 42 and the outer frame member 43 is not particularly limited, but a ferromagnetic material having large saturation magnetization such as ordinary steel such as S50C or die steel such as SKD11 is preferable.
Also, as the nonmagnetic material constituting the annular sleeve 44 and the orientation control frame member 45, known materials can be widely used. For example, austenitic stainless steel such as SUS 304, aging treated steel such as IPA 75, nonmagnetic It is sufficient to use super steel. Also, as the annular sleeve 44, a thin one having a thickness of about 0.3 to 1.5 mm is used. At this time, if the thickness of the annular sleeve 44 is 1.5 mm or less, the magnetic field acting from the outside is likely to act on the composition Cm in the annular cavity 41, and the synthesis of the annular sleeve 44 can be performed. From the viewpoint of securing, the thickness is preferably 0.3 mm or more. The annular sleeve 44 may use a magnetic material, and the orientation control frame material 45 may use a magnetic material having a smaller saturation magnetization than the inner frame material 42 and the outer frame material 43. .

Furthermore, in the present embodiment, as shown in FIG. 4A, the anisotropic magnet to be molded has, for example, a plurality of magnetic poles Mp (eight magnetic poles in the present embodiment) on the inner circumferential surface at predetermined angular intervals (in the present embodiment) It is formed every 45 degrees).
The orientation control frame member 45 is formed of an annular member in contact with the outer peripheral surface of the annular sleeve 44, as shown in FIGS. 3A and 3B, and the outer peripheral portion of the annular member is anisotropic. The thickness of the magnet varies smoothly in the same cycle as the intervals of the magnetic poles Mp, and a thin portion 45a composed of a recess is disposed at a position between the magnetic poles Mp and the magnetic poles Mp. A thick portion 45b made of a convex portion is disposed at a corresponding position. Here, the thickness and shape of the thin portion 45a and the thick portion 45b vary depending on the target surface magnetic flux density waveform of the anisotropic magnet to be formed, and are not uniquely determined.
Further, the outer frame member 43 has a shape having a hole 43c in a square pole having a square cross section, and the circumferential surface of the hole 43c contacts the thin portion 45a and the thick portion 45b of the orientation control frame member 45 correspondingly. It has an uneven portion 43d.
Furthermore, the inner frame member 42, the outer frame member 43, the annular sleeve 44 and the orientation control frame member 45 as the mold member 40 are processed into a desired shape by machining such as wire cutting, for example, and then shrink fit is performed. And is assembled by methods such as adhesion. Further, in this example, since the thin portion 45a and the thick portion 45b of the orientation control frame member 45 and the concave and convex portion 43d of the outer frame member 43 are formed to be smoothly varying, the composition in the annular cavity portion 41 Even if a strong pressure is applied to the inner frame member 42, the outer frame member 43, the annular sleeve 44, and the orientation control frame member 45, there is no concern that stress may concentrate locally and cracks may be generated. . The same applies to the following embodiments.

<External magnetic field unit>
In the external magnetic field unit 50, as shown in FIG. 2 (a), the exciting coils 51, 52 are disposed opposite to each other on the part sandwiching the mold 30, and as shown in FIG. 2 (b) By applying a magnetic field which repels each other from the outside to the mold 30 by energizing in a positive direction which is a predetermined winding direction of the coils 51, 52, a radiation direction crossing the annular cavity 41 of the mold 30 is obtained. and it is adapted to act on the external magnetic field H ₁ toward the (radial direction).
Further, as shown in FIG. 2 (c), acts an external magnetic field H _2, which is the positive direction of the both of the exciting coil 51 and 52 transverse to the cavity 41 of the mold 30 by energizing the opposite direction reverses It is possible to

Next, a method of manufacturing the anisotropic magnet according to the present embodiment will be described.
First, the mold 30 is set in a clamped state by a mold fitting unit (not shown), and then the injection unit 20 ejects the composition Cm containing the material of the anisotropic magnet into the annular cavity 41 of the mold 30 Inject and hold pressure.
Thereafter, as shown in FIG. 2 (b), when the external magnetic field H ₁ is applied by the exciting coils 51 and 52 of the external magnetic field unit 50, as shown in FIGS. 3 (a) and 3 (b), the external magnetic field H is concerned. ₁ repel each other to be directed in the radial direction (radial direction) with respect to the annular cavity 41 of the mold 30, and to magnetize the inner frame material 42 and the outer frame material 43 which are magnetic materials, thereby forming an annular cavity A magnetic field in the direction transverse to the part 41 is generated.
At this time, an orientation control frame member 45 made of a nonmagnetic material is provided between the annular hollow portion 41 and the outer frame member 43, and the thin portion 45a of the orientation control frame member 45 is compared with the thick portion 45b. Since the magnetic field is easily transmitted, the thin portion 45a of the orientation control frame member 45 functions as a focusing portion 46 for concentrating the magnetic flux. Therefore, lines of magnetic force (magnetic flux) incident from the inner frame member 42 in the radial direction with respect to the composition Cm filled in the annular cavity portion 41 are made outside through the focusing portion 46 (thin portion 45a) of the orientation control frame member 45. The orientation magnetic field H having a coarse / dense pattern of magnetic flux in which the magnetic flux is concentrated toward the focusing portion 46 of the orientation control frame material 45 in the composition Cm in the annular cavity portion 41 is obtained. Be
As a result, the composition Cm to be an anisotropic magnet to be molded is magnetically aligned along the alignment magnetic field H inclined from the radial direction, and the composition Cm has a predetermined number of inner circumferences. The magnetic pole Mp is formed as an anisotropic magnet having the magnetic pole Mp at a portion corresponding to the focusing portion 46 of the orientation control frame member 45.

Thereafter, after the anisotropic magnet is cooled and solidified, the mold 30 may be opened by a mold clamping unit (not shown), and the molded article of the anisotropic magnet may be taken out from the mold 30.
In this case, unlike the external magnetic field H ₁ at the orientation-molding process, as shown in FIG. 5 (b), in the removal step of the molded article, it is allowed to act the external magnetic field H ₂ obtained by inverting the external magnetic field H ₁ Is preferred. In this case, assuming that the magnetic material of the inner frame member 42 and the outer frame member 43 has a magnetic hysteresis characteristic as shown in FIG. 5 (a), in the orientation-molding process, the inner at the external magnetic field H ₁ Although the frame material 42 and the outer frame material 43 are magnetized to the M ₁ level, residual magnetization remains in the inner frame material 42 and the outer frame material 43 only by stopping the action of the external magnetic field H ₁ . In FIG. 5A, the horizontal axis Hout indicates the external magnetic field, and the vertical axis M indicates the magnetization level.
However, when the action of the external magnetic field H ₂ obtained by inverting the external magnetic field H _1, except that the residual magnetization of the inner frame member 42 and the outer frame member 43 is demagnetized, also demagnetize the molded article comprising anisotropic magnet It is possible. For this reason, in the taking-out step, since the restraining force by the magnetic force is reduced between the mold 30 and the molded product, it is possible to easily take out the molded product from the mold 30 by the projecting mechanism outside the illustration. .
As to the anisotropic magnet molded product obtained in such a manufacturing process, as shown in the embodiment described later, when magnetizing each magnetic pole Mp of the molded product made of an anisotropic magnet with a magnetizing device, The surface magnetic flux density waveform, which was difficult in the conventional radially oriented anisotropic magnet, can be easily adjusted to a desired waveform shape (for example, a waveform shape approximated to a sine waveform).
Furthermore, in the present embodiment, since the annular sleeve 44 is provided between the orientation control frame member 45 and the annular cavity portion 41, the composition Cm and the orientation control frame member 45 filled in the annular cavity portion 41. There is no direct contact with For this reason, even if a step portion or the like is temporarily present on a part of the inner peripheral surface of the orientation control frame member 45, there is little concern that the surface property of the molded product is impaired when the molded product is taken out from the mold 30. Although the annular sleeve 44 is used in this example, the annular sleeve 44 may not be used if the inner peripheral surface of the orientation control frame member 45 is a surface having no smooth step.

形態 Form of comparison 1
In evaluating the performance of the mold 30 according to the present embodiment, a mold 30 'according to the comparative embodiment 1 will be described as an example.
As shown in FIG. 3 (c), the mold 30 'according to the comparative embodiment 1 divides the annular cavity 41' by the inner frame material 42 'and the outer frame material 43' made of magnetic material, and further The annular sleeve 44 'is placed between the outer frame 43' and the annular cavity 41 ', and the orientation control frame 45 of the first embodiment is removed.
In this case, 'when the action of the external magnetic field H _1, as shown in FIG. 3 (c) and 4 (b), an annular cavity 41' mold 30 Compositions Cm filled in It was confirmed that an oriented magnetic field H 'in the radial direction works, and a desired waveform shape can not be obtained as the surface magnetic flux density waveform of the anisotropic magnet to be formed.

形態 Modification 1
FIG. 6A is an explanatory view showing a modified embodiment of a molding die for anisotropic magnet according to the first embodiment.
In the figure, the basic configuration of the mold 30 is substantially the same as that of the first embodiment except that a plurality of (eight in this example) magnetic poles Mp are provided on the inner peripheral surface of the annular anisotropic magnet at a predetermined interval ( In the example, it is formed every 45 degrees, and as the mold frame member 40, a cylindrical inner frame member 42 made of a magnetic material that divides the inside of the annular cavity 41 and the outside of the annular cavity 41 As a partition member, for example, a nonmagnetic material, provided between the outer frame member 43 made of a magnetic material for partitioning the space, the annular hollow portion 41 and the outer frame member 43, and dividing the outer peripheral portion of the annular hollow portion 41 An orientation control frame member 45 having an annular sleeve 44 but using an orientation control frame member 45 different from that of the first embodiment, and further, the inner circumferential surface shape of the outer frame member 43 in contact with the orientation control frame member 45 The configuration is different from that of the first embodiment. The same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the detailed description thereof is omitted here.
In this example, the orientation control frame member 45 is provided with, for example, a constant thickness annular member 47 made of a nonmagnetic material, and the slit openings 48 are formed at the same periodic intervals as the magnetic pole Mp angular intervals of the anisotropic magnet to be formed. It is intended to be opened. Here, the slit-like opening 48 is opened in the middle of each magnetic pole Mp of the anisotropic magnet to be formed. Further, since the outer peripheral surface of the orientation control frame member 45 has a circular cross section, the inner peripheral surface of the hole 43 c of the outer frame member 43 is formed to have a circular cross section.

According to the embodiment of the present modification, when the external magnetic field H ₁ acts on the annular cavity 41 of the mold 30 from the exciting coil 51 and 52 of the external magnetic field 50, as in the first embodiment, the external magnetic field H ₁ is An attempt is made to traverse the annular cavity 41 in the radial direction. At this time, as shown in FIGS. 6 (a) and 6 (b), the orientation control frame material 45 is installed on the outer peripheral side of the annular cavity 41 of the mold 30, and the slit-like opening of the orientation control frame material 45 The slit-like opening 48 functions as a focusing portion 46 for concentrating the magnetic flux since the magnetic flux easily penetrates 48 as compared with the other portions of the annular member 47. Therefore, magnetic lines of force (magnetic flux) incident from the inner frame member 42 in the radial direction with respect to the composition Cm filled in the annular cavity portion 41 pass through the focusing portion 46 (slit opening 48) of the orientation control frame member 45. An oriented magnetic field H having a coarse / dense pattern of magnetic flux in which the magnetic flux is concentrated toward the focusing portion 46 of the orientation control frame member 45 in the composition Cm in the annular cavity portion 41 will be directed to the outer frame member 43. can get.
As a result, the composition Cm to be an anisotropic magnet to be molded is magnetically aligned along the alignment magnetic field H inclined from the radial direction, and the composition Cm has a predetermined number of inner circumferences. The magnetic pole Mp is formed as an anisotropic magnet having the magnetic pole Mp at a position located in the middle between the focusing portions 46 of the orientation control frame material 45.
Thereafter, as in the first embodiment, cooling the anisotropic magnet, after solidified, the mold in an unillustrated mold clamping unit after the action of the external magnetic field H ₂ obtained by inverting the external magnetic field H ₁ 30 may be opened, and the molded article of the anisotropic magnet may be taken out of the mold 30.
Further, in this example, since the slit control openings 45 are opened at predetermined angular intervals in the orientation control frame member 45, a step portion is generated between the slit openings 48 and the edges of the slit openings 48. However, since the composition Cm and the orientation control frame member 45 are partitioned by the annular sleeve 44, when the molded article of the anisotropic magnet is taken out as in the first embodiment, There is no concern that surface properties will be lost.

Second Embodiment
FIG. 7A shows the main part of a mold for forming an anisotropic magnet according to the second embodiment.
In the figure, the basic configuration of the mold 30 is substantially the same as that of the first embodiment except that a plurality of (eight in this example) magnetic poles Mp are provided on the inner peripheral surface of the annular anisotropic magnet at a predetermined interval ( In the example, it is formed every 45 degrees, and the annular frame portion 41 is divided by the inner frame member 42 and the outer frame member 43 as the mold frame member 40 in substantially the same manner as the first embodiment. However, unlike Embodiment 1, it is provided between the annular cavity 41 and the inner frame member 42, and partitions the inner periphery of the annular cavity 41. An orientation control frame made of a nonmagnetic material that is provided between the sleeve 44, the annular sleeve 44 and the inner frame member 42, and controls the orientation magnetic field H acting on the composition Cm filled in the annular cavity 41 And a material 49.
In this example, as shown in FIGS. 7A and 7B, the orientation control frame member 49 is formed of an annular member in contact with the inner peripheral surface of the annular sleeve 44, and the inner peripheral portion shape of the annular member Is a concavo-convex shape in which the thickness changes smoothly in the same cycle as the interval of each magnetic pole Mp of the anisotropic magnet, and a thin portion 49a consisting of a recess is disposed at a location corresponding to each magnetic pole Mp A thick portion 49b made of a convex portion is disposed at a position located in the middle of Mp.
In addition, the inner frame member 42 has an uneven portion 42d in contact with the peripheral surface of the cylindrical member corresponding to the thin portion 49a and the thick portion 49b of the orientation control frame member 49.

According to this embodiment, when the action of the external magnetic field H ₁ generated by the excitation coil 51 and 52 of the external magnetic field 50, as shown in FIG. 7 (a) (b), the external magnetic field H ₁ repel one another As a result, the inner frame member 42 and the outer frame member 43, which are magnetic members, are magnetized in the radial direction (radial direction) with respect to the annular cavity 41 of the mold 30, and the direction across the annular cavity 41 Magnetic field is generated.
At this time, an orientation control frame member 49 made of a nonmagnetic material is provided between the annular hollow portion 41 and the inner frame member 42, and the thin portion 49a of the orientation control frame member 49 is compared with the thick portion 49b. Since the magnetic field is easily transmitted, the thin portion 49a of the orientation control frame 49 functions as a focusing portion 46 for concentrating the magnetic flux. For this reason, magnetic lines of force (magnetic flux) incident in the radial direction from the inner frame member 42 with respect to the composition Cm filled in the annular cavity portion 41 are out through the focusing portion 46 (thin portion 49a) of the orientation control frame member 49. An oriented magnetic field H having a coarse / dense pattern of magnetic flux in which the magnetic flux once concentrated by the focusing portion 46 of the orientation control frame material 49 is diffused to the composition Cm in the annular cavity 41 will be directed to the frame material 43. can get.
As a result, the composition Cm to be an anisotropic magnet to be molded is magnetically aligned along the alignment magnetic field H inclined from the radial direction, and the composition Cm has a predetermined number of inner circumferences. The magnetic pole Mp, specifically, a portion corresponding to the focusing portion 46 of the orientation control frame member 49 is formed as an anisotropic magnet having the magnetic pole Mp.

Third Embodiment
FIG. 8A shows the main part of a mold for forming an anisotropic magnet according to the third embodiment.
In the figure, the basic configuration of the mold 30 is substantially the same as that of the first embodiment except that a plurality of (eight in this example) magnetic poles Mp are provided on the inner peripheral surface of the annular anisotropic magnet at a predetermined interval ( In the example, it is formed every 45 degrees, and as the mold frame member 40, the inner frame member 42, the outer frame member 43, and the annular sleeve 44 are provided substantially as in the first embodiment. Unlike the first embodiment, the outer side is provided between the annular sleeve 44 and the outer frame member 43 and made of a nonmagnetic material for controlling the orientation magnetic field H acting on the composition Cm filled in the annular cavity 41. It is made of a nonmagnetic material which is provided between the orientation control frame member 45, the annular cavity 41 and the inner frame member 42, and controls the orientation magnetic field H acting on the composition Cm filled in the annular cavity 41. And an inner alignment control frame member 49 (corresponding to the alignment control frame member of the second embodiment).
In this example, the outer orientation control frame member 45 includes a thin portion 45 a and a thick portion 45 b corresponding to the orientation control frame member 45 used in the first embodiment, and the inner periphery of the hole portion 43 c of the outer frame member 43. An uneven portion 43 d in contact with the thin portion 45 a and the thick portion 45 b of the outer orientation control frame member 45 is formed on the surface.
On the other hand, the inner alignment control frame member 49 includes thin portions 49a and thick portions 49b corresponding to the alignment control frame member 49 used in the second embodiment, and the inner alignment control on the outer peripheral surface of the inner frame member 42. An uneven portion 42 d is formed in contact with the thin portion 49 a and the thick portion 49 b of the frame member 49.
The thin portion 45a and the thick portion 45b of the outer orientation control frame member 45 are disposed to face the thick portion 49b and the thin portion 49a of the inner orientation control frame 49, respectively. In the present embodiment, unlike the second embodiment, no annular sleeve is provided between the inner orientation control frame 49 and the annular cavity 41.

According to this embodiment, when the action of the external magnetic field H ₁ generated by the excitation coil 51 and 52 of the external magnetic field 50, as shown in FIG. 8 (a) (b), the external magnetic field H ₁ repel one another As a result, the inner frame member 42 and the outer frame member 43, which are magnetic members, are magnetized in the radial direction (radial direction) with respect to the annular cavity 41 of the mold 30, and the direction across the annular cavity 41 Magnetic field is generated.
At this time, an outer orientation control frame member 45 made of nonmagnetic material is provided between the annular sleeve 44 and the outer frame member 43, and the thin portion 45a of the outer orientation control frame member 45 is a thick portion 45b. In comparison, since the magnetic field is more easily transmitted, the thin portion 45a of the outer orientation control frame member 45 functions as a focusing portion 46 for concentrating the magnetic flux.
Furthermore, an inner orientation control frame member 49 made of a nonmagnetic material is provided between the annular hollow portion 41 and the inner frame member 42, and the thin portion 49a of the inner orientation control frame member 49 is a thick portion 49b. In comparison, since the magnetic field is easily transmitted, the thin portion 49a of the inner orientation control frame member 49 functions as a focusing portion 46 for concentrating the magnetic flux.
For this reason, magnetic lines of force (magnetic flux) incident from the inner frame member 42 in the radial direction with respect to the composition Cm filled in the annular cavity portion 41 become the converging portion 46 (thin portion 49a) of the inner orientation control frame member 49. And it goes to the outer frame material 43 through the converging part 46 (thin part 45 a) of the outer orientation control frame material 45.
That is, in the present embodiment, the magnetic flux once concentrated in the focusing portion 46 of the inner orientation control frame 49 is applied to the composition Cm in the annular cavity portion 41 through the focusing portion 46 of the outer orientation control frame 45. An oriented magnetic field H is obtained which has a coarse and dense pattern of magnetic flux that is directed to the
As a result, the composition Cm to be an anisotropic magnet to be molded is magnetically aligned along the alignment magnetic field H inclined from the radial direction, and the composition Cm has a predetermined number of inner circumferences. The magnetic pole Mp, specifically, a portion corresponding to the focusing portion 46 of the inner orientation control frame material 49 is formed as an anisotropic magnet having the magnetic pole Mp.
In particular, in this example, since the outer orientation control frame material 45 and the inner orientation control frame material 49 of the pair configuration are installed to sandwich the annular cavity 41, as in the first and second embodiments, The formation accuracy of the pattern of the alignment magnetic field H with respect to the composition Cm is enhanced as compared with the mode in which the alignment control frame member 45 or 49 is provided on one of the outer side or the inner side of the cavity 41.

Fourth Embodiment
FIG. 9A shows the main part of a mold for forming an anisotropic magnet according to the fourth embodiment.
The mold 30 according to the present embodiment is applied to an aspect in which a plurality of magnetic poles Mp are arranged in a plate-like anisotropic magnet, and a linear shape filled with the composition Cm containing the material of the anisotropic magnet. A magnetic field generation frame member 62, 63 made of a magnetic material is provided opposite to the mold frame member 40 so as to sandwich the linear cavity portion 61, and the mold frame member 40 is further provided with the linear cavity portion 61. A composition Cm in which a partition plate 64 as a partition member is installed between the magnetic field generation frame member 63 and the linear cavity 61 is filled between the partition plate 64 and one magnetic field generation frame member 62. Is provided with an orientation control frame member 65 capable of controlling the orientation magnetic field H acting thereon.
In this example, the orientation control frame member 65 is disposed on the side not facing the magnetic pole Mp of the anisotropic magnet to be formed, and the thickness changes smoothly in the same cycle as the interval of the magnetic pole Mp. The thin-walled portion 65a is disposed at a portion located in the middle of the magnetic pole Mp, and the thick-walled portion 65b is disposed at a portion corresponding to the magnetic pole Mp.
Further, in this embodiment, unillustrated external field device is intended for applying a external magnetic field H ₁ toward a predetermined direction which crosses the linear cavity 61, by inverting the external magnetic field H ₁ optionally It is possible to apply an external magnetic field as well.

According to this embodiment, when the action of the external magnetic field H ₁ by an unillustrated external magnetic field device, as shown in FIG. 9 (a) (b), the external magnetic field H ₁ is a linear cavity 61 intersecting The magnetic field generation frame members 62 and 63 made of a magnetic material are magnetized. At this time, the external magnetic field H ₁ is made to generate a magnetic flux crossing the composition Cm filled linearly cavity 61, the thin portion 65a of the alignment control frame member 65 is a magnetic field as compared with the thick portion 65b The thin portion 65a of the orientation control frame member 65 functions as a focusing portion 66 for concentrating the magnetic flux because it is easily transmitted.
For this reason, magnetic lines of force (magnetic flux) incident in a predetermined direction from one of the magnetic field generation frame members 62 with respect to the composition Cm filled in the linear hollow portion 61 are the converging portions 66 (thin portions 65 a of the orientation control frame 65 And the magnetic flux is concentrated toward the converging portion 66 of the orientation control frame 65 in the composition Cm in the linear cavity 61. An oriented magnetic field H is obtained.
As a result, the composition Cm to be an anisotropic magnet to be molded is magnetically aligned along the orientation magnetic field H inclined from the predetermined direction, and the composition Cm has a predetermined number of magnetic poles on one side. Specifically, it is formed as an anisotropic magnet having a magnetic pole Mp at a portion corresponding to the middle of the focusing portion 66 of the orientation control frame member 65.
Thereafter, as in the first embodiment, cooling the anisotropic magnet, after solidified, the unillustrated mold clamping unit after the action of an external magnetic field obtained by inverting the external magnetic field H ₁ (not shown) The mold 30 may be opened, and the molded article of the anisotropic magnet may be taken out of the mold 30.

Example 1
The present embodiment is an embodiment of a mold for forming an anisotropic magnet (see FIG. 3) according to the first embodiment, and eight magnetic poles Mp are formed on the inner peripheral surface of the annular anisotropic magnet. It is
In this example, the annular hollow portion 41 has an outer diameter of φ25 × an inner diameter of φ21 × length L7 mm, and the magnetic members constituting the inner frame member 42 and the outer frame member 43 are NAK 55, an annular sleeve 44 and an orientation control frame member 45 The nonmagnetic material to be processed was processed and incorporated into SUS303 respectively. The thickness of the annular sleeve 44 is 0.5 mm.
Sumitomo Metal Mining Co., Ltd. Sm-Fe-N magnet molding pellets (trade name: Wellmax S4A-7M) raw material using the mold 30 for forming anisotropic magnets of this example, cylinder temperature 210 to 260 ° C. The anisotropic magnet was manufactured by injection molding at a mold temperature of 60 to 80 ° C.
After molding, a reverse magnetic field (external magnetic field H ₂ ) was applied in the mold 30 to demagnetize the anisotropic magnet (molded product). The demagnetized molded product was easily removed by a projecting mechanism (not shown) of the mold 30, and the molded products arranged in the tray had a magnetic force that slightly adsorbed each other. The effects of the demagnetizing process are the same as in the second and third embodiments.
After magnetizing the obtained anisotropic magnet (molded article) with a magnetizing jig of inner peripheral 8 poles, the surface magnetic flux density distribution of the molded article is simulated, and the result shown in FIG. 10A is obtained. The
According to the figure, it can be understood that the molded product after magnetization is magnetized along the pole anisotropic orientation of the eight magnetic poles.
Also, when the surface flux density waveform Br of the molded article after magnetization was measured while contacting the inner peripheral surface of the molded article with the probe of the Gauss meter and rotating the molded article, a sine as shown in FIG. 10 (b) It was confirmed that a waveform shape approximated to the waveform was obtained, and its peak value was 113 mT (same as 1.13 kOe).

Example 2
The present embodiment is an embodiment of a mold for forming an anisotropic magnet according to the second embodiment (see FIG. 7), and eight magnetic poles Mp are formed on the inner peripheral surface of the annular anisotropic magnet. It is
In this example, the annular hollow portion 41 has an outer diameter of φ25 × an inner diameter of φ21 × length L7 mm, and the magnetic members constituting the inner frame member 42 and the outer frame member 43 are NAK 55, an annular sleeve 44 and an orientation control frame member 49 The nonmagnetic material to be processed was processed and incorporated into SUS303 respectively. The thickness of the annular sleeve 44 is 0.5 mm.
Sumitomo Metal Mining Co., Ltd. Sm-Fe-N magnet molding pellets (trade name: Wellmax S4A-7M) raw material using the mold 30 for forming anisotropic magnets of this example, cylinder temperature 210 to 260 ° C. The anisotropic magnet was manufactured by injection molding at a mold temperature of 60 to 80 ° C.
The resulting anisotropic magnet (molded article) is magnetized by an inner peripheral 8 pole magnetizing jig, and then the surface magnetic flux density waveform Br of the molded article is measured using a gauss meter as described above. It can be confirmed that a waveform shape approximate to a sine waveform as shown in 11 can be obtained, and its peak value is 199 mT (same as 1.99 kOe).

Example 3
The present embodiment is an embodiment of a mold for forming an anisotropic magnet (see FIG. 8) according to the third embodiment, and eight magnetic poles Mp are formed on the inner peripheral surface of the annular anisotropic magnet. It is
In this example, the annular hollow portion 41 has an outer diameter of φ25 × an inner diameter of φ21 × length L7 mm, the magnetic members constituting the inner frame member 42 and the outer frame member 43 are NAK 55, an annular sleeve 44, an outer orientation control frame member 45 and The nonmagnetic material which comprises the inner orientation control frame material 49 processed and integrated SUS303, respectively. The thickness of the annular sleeve 44 is 0.5 mm.
Sumitomo Metal Mining Co., Ltd. Sm-Fe-N magnet molding pellets (trade name: Wellmax S4A-7M) raw material using the mold 30 for forming anisotropic magnets of this example, cylinder temperature 210 to 260 ° C. The anisotropic magnet was manufactured by injection molding at a mold temperature of 60 to 80 ° C.
The obtained anisotropic magnet (molded product) is magnetized by an inner peripheral 8 poles magnetizing jig, and then the surface magnetic flux density waveform Br of the molded product is measured using a gauss meter, as shown in FIG. It can be confirmed that a waveform shape approximate to a sinusoidal waveform as shown in is obtained, and its peak value is 196 mT (same as 1.96 kOe).
Furthermore, it was confirmed that the surface magnetic flux density waveform Br / Bp of the molded product normalized with the peak value Bp is a waveform showing polar anisotropy very close to a sine waveform as shown in FIG. 12 (b).

比較 Comparative Example 1
The present comparative example is a mold for forming an anisotropic magnet incorporating a permanent magnet, in which four magnetic poles Mp are formed on the outer peripheral surface of an annular anisotropic magnet.
In this example, as shown in FIG. 13A, the mold 30 ′ divides the annular cavity 71 by the mold frame member 70, and, for example, N, N at the site facing the outer periphery of the annular cavity 71. A plurality of (eight in this example) orientation permanent magnets 72 in which S are alternately arranged two by two are incorporated, and an orientation magnetic field is given by the orientation permanent magnets 72 to the composition Cm filled in the annular cavity 71 It is a thing. In the present embodiment, the mold frame member 70 includes an inner frame member 73 which divides the inner side of the annular cavity 71, an outer frame member 74 which holds the outer peripheral side of the orientation permanent magnet 72, and an annular cavity portion. An annular sleeve 75 is provided which defines the outer periphery of the outer circumferential surface 71 and holds the inner circumferential side of the orientation permanent magnet 72.
In this example, the ring-shaped cavity 71 has an outer diameter φ27.6 × inner diameter φ19 × length L27 mm, and eight permanent magnet 72 for orientation use NdFeB sintered magnets (42 MGOe).
Then, a mold for molding the anisotropic magnet produced is incorporated into a matrix, and a Sumitomo Metal Mining Co., Ltd. Sm-Fe-N based magnet molding pellet (trade name: Wellmax S3A-12M) raw material is used at a cylinder temperature of 210. The anisotropic magnet was produced by injection molding at ~ 260 ° C and a mold temperature of 60-80 ° C.
As shown in FIG. 13 (b), the obtained anisotropic magnet (molded article) is magnetized by means of a magnetizing jig with four outer peripheral poles, and the surface magnetic flux density waveform Br of the molded article is measured using a gauss meter. A waveform shape approximating a sine waveform was obtained, and its peak value was 206 mT (the same as 2.06 kOe).
However, since the molded product after molding could not be easily removed only by the protrusion mechanism of the mold 30 ′, the molded product was gripped and taken out by hand. When arranging the taken out molded products on a tray, they were adsorbed in a cylindrical shape in order to strongly adsorb to the arranged molded products. At the time of adsorption, attention was paid to the cracks and chips due to the impact.
This mold required 1.7 times the cost and twice the time of Example 1.

比較 Comparative Example 2
The present comparative example is an aspect in which the orientation control frame member 45 is removed from the mold for forming an anisotropic magnet shown in the first embodiment, and the anisotropic magnet is formed by applying an external magnetic field. . However, in the present comparative example, the annular hollow portion 41 has an outer diameter of φ25 × an inner diameter of φ21 × length of 30 mm.
In this comparative example, when the surface magnetic flux density waveform Br of the molded article after magnetizing was measured in the same manner as in Example 1, it is understood that as shown in FIG. Ru. From this, it is understood that, in order to make the surface magnetic flux density waveform of the molded product desired, the orientation control frame material 45 or 49 is indispensable as a constituent feature of the mold for forming an anisotropic magnet.

DESCRIPTION OF SYMBOLS 1 Mold for molding 2 Mold frame material 3 Hollow part 4 (4a, 4b) Magnetic field generation frame material 5 Orientation control frame material 6 Focusing part 7 Thin part 8 Thick part 9 Partition member Cm Composition H, H 'Orientation magnetic field H ₁ external magnetic field
H ₂ external magnetic field Mp magnetic pole 20 injection unit 21 cylinder 22 hopper 23 heater 24 screw rod 25 injection port 26 supply path 30, 30 'mold 31 connection unit 32 fixed side mounting plate 34 movable side mounting plate 35 movable side plate PL gold Mold separation surface 40 Mold frame material 41, 41 'Annular cavity 42, 42' Inner frame material 42d Irregularities 43, 43 'Outer frame material 43c Hole 43d Irregularities 44, 44' Annular sleeve 45 Orientation control frame Material 45a Thin portion 45b Thick portion 46 Converging portion 47 Annular member 48 Slit-like opening 49 Orientation control frame member 49a Thin portion 49b Thick portion 50 External magnetic field unit 51 Excitation coil 52 Excitation coil 61 Linear cavity 62 Magnetic field generation frame Material 63 Magnetic field generation frame material 64 Partition plate 65 Orientation control frame material 65a Thin-walled part 65b Thick-walled part 66 Focused part 70 Gold Within frame frame member 71 annular cavity portion 72 oriented permanent magnet 73 material 74 outer frame member 75 annular sleeve

Claims (10)

A mold frame material which defines a cavity which can be filled with a composition containing a material of an anisotropic magnet to be molded, and which can arrange the cavity in an externally acting magnetic field;
The mold frame material is disposed to face the hollow portion so as to sandwich the hollow portion, and a magnetic field generation frame member made of a magnetic material that generates a magnetic field in a direction crossing the hollow portion;
The direction of magnetization is provided in a portion facing at least one of the hollow portions of the magnetic field generation frame material sandwiching the hollow portion, and the direction of magnetization so that the surface magnetic flux density waveform of the anisotropic magnet to be formed has a desired waveform shape. A mold for forming an anisotropic magnet, comprising: a nonmagnetic material for controlling an orientation magnetic field to be determined or an orientation control frame material made of a magnetic material having a saturation magnetization smaller than that of the magnetic field generation frame material. In the mold for forming an anisotropic magnet according to claim 1,
A mold for forming an anisotropic magnet, wherein the orientation control frame member has a thin-walled portion whose thickness changes in the same cycle as an interval between magnetic poles of the anisotropic magnet to be formed. In the mold for forming an anisotropic magnet according to claim 2,
A mold for forming an anisotropic magnet, wherein the orientation control frame member has an unevenness whose thickness changes smoothly in the same cycle as an interval between magnetic poles of the anisotropic magnet to be formed. In the mold for forming an anisotropic magnet according to claim 1,
A mold for forming an anisotropic magnet, comprising: a partition member for partitioning between the magnetic pole side of an anisotropic magnet to be formed in the hollow portion and the orientation control frame member. In the mold for forming an anisotropic magnet according to claim 1,
The mold frame material defines an annular or arc-shaped cavity,
A mold for forming an anisotropic magnet, characterized in that an externally acting magnetic field acts in a direction radially across the cavity. In the mold for forming an anisotropic magnet according to claim 5,
The orientation control frame member is disposed on the outer peripheral side of the annular or arc-shaped hollow portion, and forms a magnetic pole of an anisotropic magnet to be formed on the inner peripheral side or the outer peripheral side in the hollow portion. Molds for the anisotropic magnet. In the mold for forming an anisotropic magnet according to claim 5,
The orientation control frame member is disposed on the inner peripheral side of the annular or arc-like hollow portion, and forms a magnetic pole of an anisotropic magnet to be formed on the inner peripheral side or the outer peripheral side in the hollow portion. Mold for forming anisotropic magnet. In the mold for forming an anisotropic magnet according to claim 5,
The orientation control frame material is disposed on the outer circumferential side and the inner circumferential side of the annular or arc-shaped cavity, and one orientation control frame material corresponds to the magnetic pole of the anisotropic magnet to be formed in the cavity. A mold for forming an anisotropic magnet, comprising: a focusing portion where magnetic flux concentrates, and the other orientation control frame material having the focusing portion at a portion corresponding to the magnetic poles. When manufacturing an anisotropic magnet using the mold for forming an anisotropic magnet according to any one of claims 1 to 8,
Filling the composition including the material of the anisotropic magnet to be formed in the cavity of the forming mold;
An orientation / forming step of magnetically orienting the composition filled in the cavity by forming a magnetic field from the outside on the molding die after the filling step, and forming the composition into a predetermined shape;
A method of manufacturing an anisotropic magnet, comprising: a removal step of cooling the anisotropic magnet molded in the orientation and molding step and taking it out from the molding die. In the method of manufacturing an anisotropic magnet according to claim 9,
The method for producing an anisotropic magnet, wherein the taking-out step is performed by applying a magnetic field obtained by inverting the magnetic field at the time of the orientation and forming process to the molding die.