JP2018092988A - Multiple magnetization unit permanent magnet, manufacturing method thereof, mold, and magnetic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which two or more permanent magnets having mutually different magnetization directions are liable to fall apart due to suction, repulsion, or the like between the permanent magnets in a configuration of a Halbach magnetic circuit by bonding the permanent magnets.SOLUTION: Multiple magnetization unit permanent magnets having two or more magnet regions with different magnetization directions in a single permanent magnet is provided. A mold used to form multiple magnetization unit permanent magnets and a method for manufacturing a permanent magnet using a mold are disclosed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a multi-magnetization unit permanent magnet and a method for manufacturing the same. Furthermore, this invention relates to the magnetic circuit comprised by the metal mold | die used for a manufacturing method, and a multiple magnetization unit permanent magnet.

  In general, a permanent magnet has a magnetization direction (that is, uniaxial anisotropy) in a uniaxial direction as a single permanent magnet, and has magnetic poles composed of an N pole and an S pole on opposite surfaces.

  This type of permanent magnet is widely used in various devices such as motors, generators, electromagnetic actuators and electromagnetic sensors. In these devices, a plurality of permanent magnets are usually arranged.

  A Halbach magnetic circuit has been proposed as a magnetic circuit for generating a magnetic field having a high magnetic flux density in a magnetic field generation space.

  Patent Document 1 discloses that a magnetic field generation device including a Halbach magnetic circuit is applied to a magnetic field extrusion molding device. Further, Patent Document 1 discloses a method of applying a magnetic field to a compound composed of magnet powder and resin by using the magnetic field generator to obtain an oriented molded body, and obtaining a magnet by the molded body. . Further, it is described that a molded body having stable magnetic field strength, magnetic field uniformity, and magnetic field parallelism can be obtained by using the Halbach magnetic circuit.

  Patent Document 2 discloses the use of a Halbach magnetic circuit as a magnetic circuit for a linear motor. Specifically, Patent Document 2 has a first sintered magnet having a magnetization direction orthogonal to the main surface, and a magnetization direction inclined at a predetermined angle with respect to the orthogonal direction of the main surface at both ends thereof. A magnet unit having a second sintered magnet is clarified.

  The magnet unit described in Patent Document 2 has a configuration in which two sintered magnets are bonded to both ends of a first sintered magnet with an adhesive and the surface is covered with a coating.

  Patent document 3 is disclosing the anisotropic magnet used for the rotor of a motor. The anisotropic magnet described in Patent Document 3 has a crescent-shaped cross section, and has a region magnetized in a direction inclined from the orientation direction and a region magnetized in the orientation direction. Further, Patent Document 3 describes that the magnetization direction is controlled by inclining the magnetizing magnetic field with respect to the orientation direction of the sintered magnet to control the magnetization direction.

JP 2005-101437 A JP 2010-50440 A JP 2010-258181 A

  Patent Document 1 merely discloses the use of a Halbach magnetic circuit for a magnetic field generator, and does not mention any magnets that constitute the Halbach magnetic circuit.

  In addition, as in Patent Document 2, when a Halbach magnetic circuit is configured by cutting and combining a plurality of magnets having uniaxial anisotropy, the accuracy when cutting the shape of the magnet is deteriorated. The combined work has the disadvantage of poor productivity. Furthermore, when a Halbach magnetic circuit is configured by combining a plurality of magnets having different magnetization directions, there is a drawback that misalignment due to attraction between magnets and repulsion is likely to occur.

  Furthermore, Patent Document 3 only discloses an anisotropic magnet having a crescent-shaped cross section, and does not mention anything about a magnet having a cross-sectional shape other than the crescent-shaped cross section (for example, a rectangular parallelepiped shape or an arc shape). Further, Patent Document 3 does not suggest any application to the Halbach magnetic circuit.

  An object of the present invention is to provide a magnet (that is, a multi-magnetization unit permanent magnet) having magnetic anisotropy in a plurality of directions different from each other and forming magnetization in a plurality of directions in a single magnet.

  It is another object of the present invention to provide a method for manufacturing a multi-magnetization unit permanent magnet having a plurality of magnetic anisotropies, that is, a plurality of different magnetization directions.

  Still another object of the present invention is to provide a mold used in manufacturing the multi-magnetization unit permanent magnet.

  Another object of the present invention is to provide a Halbach magnetic circuit constituted by the multi-magnetization unit permanent magnet.

According to the first aspect of the present invention, there are a plurality of first main surfaces, a second main surface facing the first main surface, and a plurality of side surfaces connecting the first and second main surfaces. Magnetizing unit permanent magnet,
A first magnet region provided in the multi-magnetization unit permanent magnet and having a first magnetization direction parallel to the first and second main surfaces;
A second magnet adjacent to the first magnet region in the plurality of magnetized unit permanent magnets and having a second magnetization direction substantially perpendicular to the first magnetization direction of the first magnet region. A multi-magnetization unit permanent magnet characterized by having a region is obtained.

According to a second aspect of the present invention, there is provided a mold for a dust magnet in which a cavity having a predetermined shape having a thickness direction and a length direction intersecting the thickness direction is defined.
First and second non-magnetic components that respectively define first and second thickness direction surfaces in the thickness direction opposite to the thickness direction of the cavity;
The first and second layers are provided so as to sandwich the first nonmagnetic component, and are disposed on the first thickness direction surface side so as to partially overlap the first length direction surface of the cavity. Magnetic parts,
3rd and 4th which are provided so that the 2nd nonmagnetic part may be inserted, and are arranged on the 2nd thickness direction surface side so that it may overlap with the 2nd length direction surface of the cavity Magnetic parts,
3. A dust magnet gold comprising third and fourth nonmagnetic parts defining first and second lengthwise surfaces of the cavity that do not overlap the first and second magnetic parts A mold is obtained.

  According to the third aspect of the present invention, the first step of preparing the mold described in the second aspect and filling the mold with magnetic powder, the first and second magnetic components, A second step of applying a magnetic field between the third and fourth magnetic components to determine a direction of easy magnetization in the length direction of the magnetic powder, and rotating the mold by 90 °, The direction of easy magnetization of the magnetic powder on both sides sandwiching the central part of the rectangular parallelepiped shape by applying a magnetic field between the second and fourth magnetic parts and the second and fourth magnetic parts is substantially the same as the length direction. A method of producing a permanent magnet having a plurality of magnetization units, comprising: a third step of determining a perpendicular direction; and obtaining a green compact in which a central portion and easy magnetization directions on both sides sandwiching the central portion are orthogonal to each other Is obtained.

  According to the fourth aspect of the present invention, there is obtained a Halbach magnetic circuit configured by combining a plurality of multi-magnetization unit permanent magnets described in the first aspect.

  Since the multi-magnetization unit permanent magnet according to the present invention has a plurality of magnetic anisotropies in a single permanent magnet, the number of the Halbach magnetic circuits configured by arranging a plurality of permanent magnets having different magnetization directions is less permanent. Can be configured with magnets.

It is a figure which shows an example of the external appearance structure of the multiple magnetization unit permanent magnet which concerns on this invention. It is a top view explaining the multiple magnetization unit permanent magnet of this invention in principle. It is a top view which shows the example of the magnetization direction of the multiple magnetization unit permanent magnet which concerns on this invention. It is sectional drawing which shows the metal mold | die for dust magnets used with the manufacturing method of the multiple magnetization unit permanent magnet which concerns on this invention. It is a perspective view explaining the magnetic component which comprises the metal mold | die shown by FIG. It is a figure explaining 1 process of the magnetic field application in the manufacturing method which concerns on this invention. It is a figure explaining the other process of the magnetic field application in the manufacturing method which concerns on this invention. It is a figure explaining 1 process of the process of the magnetization which concerns on this invention. It is a figure explaining the other process of the process of the magnetization which concerns on this invention. It is a figure explaining the other process of the process of the magnetization which concerns on this invention. It is the figure which showed arrangement | positioning of the magnet when making a linear motor using this invention. It is the figure which showed the aspect of the process in the case of utilizing for a rotary motor or a generator using this invention. It is the figure which showed arrangement | positioning of the magnet in the case of utilizing for a rotary motor or a generator using this invention. It is the figure which showed the position which extract | collects the sample for confirming the effect of invention when implementing this invention.

  With reference to FIG. 1, the structure of the multi-magnetization unit permanent magnet 10 according to the present invention will be described in principle. The multi-magnetization unit permanent magnet 10 shown in FIG. 1 has a rectangular parallelepiped shape, and in the following, the left-right direction of the figure is the length direction, the up-down direction is the thickness direction, and the surface facing the upper side of the figure is the first The main surface and the lower surface opposite to the first main surface will be described as the second main surface. In addition, the illustrated plural magnetized unit permanent magnets are first and second side surfaces that oppose each other in the length direction and are connected to the first and second main surfaces in the left-right direction in the drawing, the front side and the rear side in the drawing, respectively. Has a front surface and a back surface.

  Here, the distance and direction between the first and second side surfaces are the length and length direction, the distance and direction between the first and second main surfaces are the thickness and thickness direction, and the front and back surfaces. The distance and direction between the two will be described as the width and the width direction.

  The illustrated multi-magnetization unit permanent magnet 10 includes a first magnet region 11 and a second magnet region 12 adjacent to the first magnet region 11 in the central region in the length direction. In the illustrated example, the second magnet region 12 is adjacent to both sides of the first magnet region 11. That is, the second magnet region 12 includes first and second side magnet regions 121 and 122.

  The multi-magnetization unit permanent magnet 10 according to the present invention is characterized in that the first magnetization direction in the first magnet region 11 and the second magnetization direction in the second magnet region 12 are substantially perpendicular to each other. It is said. Further, the second magnetization directions in the first and second side magnet regions 121 and 122 constituting the second magnet region are 180 degrees different from each other.

  When the Halbach magnetic circuit is constituted by the illustrated plural magnetized unit permanent magnets 10, the magnetic circuit that has conventionally required three permanent magnets can be constituted by a single plural magnetized unit permanent magnet.

  Referring to FIG. 2, the easy magnetization direction when the plurality of magnetization unit permanent magnets 10 shown in FIG. 1 is viewed from the front side is shown. More specifically, the first magnet region 11 of the multi-magnetization unit permanent magnet 10 shown in FIG. 2 is oriented in the length direction parallel to the first and second main surfaces, and in the length direction. It has an easy magnetization direction. That is, the first magnetization direction of the first magnet region 11 is the length direction (left-right direction) of the plurality of magnetization unit permanent magnets 10, and the first magnet region 11 is magnetized in the length direction.

  On the other hand, the first and second side magnet regions 121 and 122 constituting the second magnet region 12 have a second magnetization that is substantially perpendicular to the first magnetization direction (that is, the thickness direction). Magnetized in the direction.

  With reference to FIG. 3, the specific magnetization direction in the multi-magnetization unit permanent magnet 10 will be described.

  That is, in the example of FIG. 3, the first magnetization direction has the first magnetization direction from the left to the right in the figure, while the second side magnet regions 121 and 122 have the first magnetization direction. Is magnetized in a substantially perpendicular direction. The first side magnet region 121 is magnetized in the direction from the main surface 1 to the main surface 2, and the second side magnet region 122 is magnetized in the direction from the main surface 2 to the main surface 1. Therefore, the second magnetization direction in the side magnet region differs by 180 degrees.

  With reference to FIG. 4, the method to manufacture the multi-magnetization unit permanent magnet 10 shown in FIG.2 and FIG.3 is demonstrated. The multi-magnetization unit permanent magnet 10 shown in FIGS. 2 and 3 is obtained by melting and pulverizing an alloy made of magnetic powder and then molding it by pressing in a magnetic field.

  Here, the metal mold | die for dust magnets used for the press in a magnetic field is demonstrated first.

  Referring to FIG. 4, an example of a dust magnet mold 20 according to an embodiment of the present invention is shown. The mold 20 shown in FIG. 4 has a rectangular parallelepiped cavity 30 at the center thereof. Each surface of the cavity 30 corresponds to each surface of the multi-magnetization unit permanent magnet shown in FIG.

  The illustrated mold 20 includes four parts made of a magnetic material and four parts made of a non-magnetic material.

  More specifically, the mold 20 includes first and second nonmagnetic components 21 and 22 having first and second lengthwise side surfaces facing each other in the length direction of the cavity 30, and first nonmagnetic. Is provided so as to sandwich the component 21, and is provided so as to sandwich the first and second magnetic components 25, 26 and the second non-magnetic component partially defining one longitudinal surface of the cavity 30, The third and fourth magnetic components 27 and 28 that partially define the longitudinal direction surface of the cavity 30, and the third and fourth portions that are opposed to each other and are provided at the center of the longitudinal direction surface of the cavity 30. Nonmagnetic parts 31 and 32 are provided. The first to fourth magnetic parts 25, 26, 27, and 28 are made of ferromagnetic carbon steel, such as JIS45C, SK6, SK7, SKD11, SKD12, or the like.

  Further, in the illustrated mold 20, the longitudinal surface of the cavity 30 is partially defined by the first and third magnetic components 25, 27, the second and fourth magnetic components 26, 28. And a partial surface defined by the third non-magnetic component 31 and the fourth non-magnetic component 32.

  The first to fourth nonmagnetic parts 21, 22; 31, 32 are made of a nonmagnetic material, for example, stainless steel (SUS304, SUS316). Of these, the first and second nonmagnetic parts 21 and 22 each have a protruding portion that defines the thickness direction and width direction surfaces of the cavity 30 and an extended portion that extends from the protruding portion to the outside of the cavity 30. doing.

  The first to fourth magnetic components 25, 26, 27, and 28 are in contact with the protruding portions of the first and second nonmagnetic components 21, 22 and are one of the longitudinal surfaces of the cavity 30. The first contact surface a extending to the portion, the second and third contact surfaces b and c contacting the extended portions of the nonmagnetic components 21 and 22, and the third and fourth nonmagnetic components 31 and 32. The fourth and fifth contact surfaces d and e are in contact with each other. In addition, in FIG. 4, although each contact surface was demonstrated about the 1st magnetic component 25, the other magnetic components 26-28 also have the same contact surface.

  FIG. 5 is a perspective view for specifically explaining the magnetic component 25 shown in FIG. As is apparent from FIG. 5, the magnetic component 25 has the first to third contact surfaces a, b, c that contact the nonmagnetic component 21, and the fourth and fifth contact surfaces that contact the nonmagnetic component 31. d and e are provided.

  Since the structures of the non-magnetic components 21, 22, 31, and 32 that are in contact with the magnetic components 25 to 28 are obvious from FIG. The first to fourth magnetic components 25, 26, 27, and 28 and the first to fourth nonmagnetic components 21, 22, 31, and 32 are configured to be detachable by screws or the like.

  Next, a method for manufacturing a multi-magnetization unit permanent magnet according to an embodiment of the present invention will be described. Here, it is assumed that the multi-magnetization unit permanent magnet 10 shown in FIG. 1 having a length of 45 mm, a thickness of 12 mm, and a width of 12 mm is manufactured using the dust magnet mold 20 shown in FIG.

  First, as a magnetic alloy, Pr-Nd30.0%, B1.0%, Dy1.0%, Ho1.0%, Al1.2%, Co1.5%, Cu0.2%, Ga0.2%, Nb0. An alloy comprising 3% balance Fe and inevitable impurities is prepared. In addition,% is weight%.

  Next, the alloy is melted, rapidly cooled, and then roughly pulverized with a hydrogen pulverizer. Subsequently, using a jet mill, the powder is pulverized to an average particle size of 3 to 3.5 μm to obtain a magnetic powder.

  Subsequently, the obtained magnetic powder is pressed in a magnetic field by using a dust magnet mold 20 shown in FIG. 4 to obtain a magnetic powder compact.

  Thereafter, sintering is performed in a vacuum at a temperature of 1130 ° C. for 2 hours, and after rapid cooling, primary aging is performed at 910 ° C. Next, the multi-magnetization unit permanent magnet shown in FIG. 1 is obtained by aging at 500 ° C. for 5 hours.

  Next, the above-described magnetic field press will be specifically described with reference to the drawings.

  Referring to FIG. 6, the above-described magnetic powder is filled in the cavity 30 of the dust magnet mold 20. The size of the cavity 30 is the same as the size of the magnetic green compact after compacting. Here, the length is 55.6 mm, the thickness is 14.8 mm, and the width is 14.8 mm. In this example, 49.5 g of magnetic powder was filled in the cavity 30 having the above size.

  By using the cavity 30 to sinter the magnetic green compact and perform the above-described processing, the multi-magnetization unit permanent magnet is a sintered magnet multi-magnetization unit permanent magnet having a size of 45 × 12 × 12 mm. was gotten.

  Further, the magnetization direction (magnetic anisotropy) at the central portion 1/3 in the length direction is the length direction, and the magnetization directions (magnetic anisotropy) in the thickness direction (12 mm) at each 1/3 of both ends. A multi-magnetization unit permanent magnet showing the thickness direction was obtained.

  If it demonstrates concretely, as shown in FIG. 6, the magnetic field generator 40 will be arrange | positioned on both sides of a metal mold | die so that the metal mold | die 20 for dust magnets may be pinched | interposed. The illustrated magnetic field generator 40 generates a magnetic field from the left to the right in FIG. 6, that is, in the direction indicated by the arrow 43. The magnetic field generator 40 includes a yoke.

First, the first and second magnetic components 25 and 26 of the mold 20 and the third and fourth magnetic components 26 and 27 are brought into contact with the electromagnet yoke of the magnetic field generating device 40 to generate a magnetic field of 20000 Gauss or more. Apply. At this time, a pressure of 1 kg / cm ² is applied to the die constituted by the third and fourth nonmagnetic parts 31 and 32, and compacted. The pressure in this case is such a pressure that the magnetic powder does not protrude from the mold 20.

  In this pressure state, the easy axis of magnetic compact is oriented in the magnetic field direction. The first and second magnetic components 25 and 26 and the third and fourth magnetic components 27 and 28 are in partial contact with the upper and lower main surfaces of the cavity 30 in the length direction. Therefore, the magnetic flux from the first and second magnetic parts 25 and 26 flows intensively to the magnetic powder filled in the central region of the cavity 30 and magnetizes the central region of the dust magnetic material in the length direction. As a result, both end regions and the central region of the magnetic powder compact are oriented in the length direction, and the easy magnetization direction of the entire magnetic powder compact is in the length direction.

  Next, the die is once pulled up, the dust magnet mold 20 is rotated 90 degrees, and the electromagnet yoke of the magnetic field generator 40 is brought into contact with the dust magnet mold 20 again.

  Referring to FIG. 7, there is shown a case where the dust magnet mold 20 is rotated 90 degrees clockwise and brought into contact with the magnetic field generator 40. As is apparent from the figure, the fourth and third non-magnetic components 32 and 31 are in contact with the magnetic field generator 40, while the second magnetic component 26 and the fourth magnetic component 28 are in one magnetic field generator 40. Further, the first and third magnetic components 25 and 27 come into contact with the other magnetic field generator 40.

  Further, the second and first magnetic parts 26 and 25 are in contact with one end of the powder magnetic material filled in the cavity 30 in the thickness direction, and the fourth and third magnetic parts 28 and 27 are pressed. It is in contact with the other end of the powder magnetic body in the thickness direction.

In this state, the magnetic field generator 40 generates a magnetic field of 20000 Gauss or more and presses at a pressure of ² t / cm ² .

  As a result, the magnetic flux is made of a ferromagnetic material, and flows between two pairs of magnetic components arranged at the end of the cavity 30, and only a magnetic flux of about the leakage magnetic flux flows in the central portion. Therefore, it was confirmed that the direction of easy magnetization of the magnetic powder in the central portion was not sufficiently rotated. As a result, the easy magnetization direction in the length direction of the central portion does not change, and the regions on both sides sandwiching the central portion are oriented in the thickness direction perpendicular to the easy magnetization direction in the thickness direction in the thickness direction. It has a direction of easy magnetization in the vertical direction.

  Thereafter, by sintering and compacting the magnetic powder magnetic body, and performing magnetization as described later, the magnetization direction in the central portion and the magnetization directions on both sides sandwiching the central portion are substantially orthogonal to each other. A permanent magnet was obtained.

  The magnetic characteristics in each region of the obtained multi-magnetization unit permanent magnet were measured.

Here, as shown in FIG. 14, Table 1 shows the result of cutting out the portions A to E of the completed magnet and measuring the magnetic characteristics of the AE portion.

  From this result, it can be seen that the central portion has an easy magnetization direction in the length direction, and both ends have an easy magnetization direction in the thickness direction.

  FIG. 8 shows a method of magnetizing in the first magnetization direction. The magnet is sandwiched between the magnetic poles so that the length of the magnet faces the magnetic pole, and a current is passed through the coil to generate a magnetic field of 25,000 gauss or more and magnetize. Magnetization may be performed using a solenoid coil instead of the electromagnet. Thereby, the first magnetization region is magnetized.

  FIG. 9 shows a method of magnetization of the first side magnetization region. The magnetic poles of the electromagnet are arranged so as to sandwich the side magnetized region 11 of the magnet 10 magnetized according to the mode of FIG. 8, and a current is passed through the electromagnet so that the magnetic flux flows from the direction of the main surface 1 to the direction of the main surface 2. A magnetic field of 25,000 gauss or more is generated in the part. Then, the side magnetization region 1 is magnetized in the direction from the main surface 1 to the main surface 2.

  FIG. 10 shows a method of magnetizing the second side magnet region. In FIG. 10, the magnetic poles of the electromagnet are arranged so as to sandwich the second side magnet region of the magnet 10 in which the first magnetized region and the first side magnetized region are magnetized, and the direction from the main surface 2 to the main surface 1 An electric current is passed through the electromagnet so that the magnetic flux flows to the magnetic field, and a magnetic field of 25,000 gauss or more is generated in this portion. Then, the side magnetized region 2 is magnetized in the direction from the main surface 2 to the main surface 1.

  Thus, a multi-magnetization unit permanent magnet as shown in FIG. 3 is completed.

  An example of configuring an actual motor using the completed magnet unit is shown below.

  FIG. 11 shows an arrangement when a plurality of magnetized unit permanent magnets are used for a linear motor.

  FIG. 12 shows a processing method in the case of using a plurality of magnetized unit permanent magnets for a rotary motor or a generator. Thereby, a tile-shaped multi-magnetization unit permanent magnet as shown in FIG. 12 is produced. This is arranged as shown in FIG. 13 to form a rotary motor or a generator.

  By using the multi-magnetization unit permanent magnet according to the present invention, a Halbach magnetic circuit can be easily created, and when applied to a motor, a generator, etc., a motor, a generator, etc. having 1.5 times the efficiency are obtained. be able to.

DESCRIPTION OF SYMBOLS 10 Multi-magnetization unit permanent magnet 11 which concerns on this invention 1st magnet area | region 12 2nd magnet area | region 121 1st side magnet area | region 122 2nd side magnet area 20 Molds 21 and 22 for dusting magnets 1st , Second nonmagnetic component 25 to 28 first to fourth magnetic component 30 cavity 31, 32 third and fourth nonmagnetic component 40 magnetic field generator 43 direction of magnetic field

Claims (10)

A multi-magnetization unit permanent magnet having a first main surface, a second main surface opposite to the first main surface, and a side surface coupling between the first and second main surfaces,
A first magnet region provided in the plurality of magnetization unit permanent magnets and having a first magnetization direction orthogonal to the first and second main surfaces;
A second magnet adjacent to the first magnet region in the plurality of magnetized unit permanent magnets and having a second magnetization direction substantially perpendicular to the first magnetization direction of the first magnet region. A multi-magnetization unit permanent magnet comprising a region.   The first magnet region is provided in a central portion of the plurality of magnetization unit permanent magnets, and the second magnet region is provided on both sides sandwiching the central portion of the plurality of magnetization unit permanent magnets. The multi-magnetization unit permanent magnet according to claim 1, wherein the multi-magnetization unit permanent magnet is constituted by a side magnet region.   3. The multi-magnetization unit permanent magnet according to claim 2, wherein the second magnetization directions in the first and second side magnet regions have opposite polarities.   The said multiple magnetization unit permanent magnet is a rectangular parallelepiped shape, The multiple magnetization unit permanent magnet as described in any one of Claims 1-3 characterized by the above-mentioned.   A Halbach magnetic circuit configured by combining a plurality of multi-magnetization unit permanent magnets according to any one of claims 1 to 4. A mold for a dust magnet in which a cavity having a predetermined shape having a thickness direction and a length direction intersecting the thickness direction is defined inside,
First and second non-magnetic components that respectively define first and second thickness direction surfaces in the thickness direction opposite to the thickness direction of the cavity;
The first and second layers are provided so as to sandwich the first nonmagnetic component, and are disposed on the first thickness direction surface side so as to partially overlap the first length direction surface of the cavity. Magnetic parts,
3rd and 4th which are provided so that the 2nd nonmagnetic part may be inserted, and are arranged on the 2nd thickness direction surface side so that it may overlap with the 2nd length direction surface of the cavity Magnetic parts,
3. A dust magnet gold comprising third and fourth nonmagnetic parts defining first and second lengthwise surfaces of the cavity that do not overlap the first and second magnetic parts Type.   The mold for a dust magnet, wherein the cavity has a rectangular parallelepiped shape having the thickness direction and the length direction longer than the thickness direction. Prepare the mold according to claim 7,
A first step of filling the mold with magnetic powder;
A second step of applying a magnetic field between the first and second magnetic components and the third and fourth magnetic components to determine an easy magnetization direction in the longitudinal direction of the magnetic powder;
Magnetic powder on both sides sandwiching the central part of the rectangular parallelepiped shape by applying a magnetic field between the first and third magnetic parts and the second and fourth magnetic parts by rotating the mold at 90 ° C. A third step of determining an easy direction of magnetization in a direction substantially perpendicular to the length direction;
A method of manufacturing a multi-magnetization unit permanent magnet comprising: a green compact including a central portion and easy magnetization directions on both sides sandwiching the central portion.   The multi-magnetization unit permanent magnet according to claim 8, further comprising a step of compacting the magnetic powder to form the green compact in at least one of the second and third steps. Manufacturing method.   10. The multi-magnetization unit permanent magnet according to claim 9, further comprising a step of magnetizing the green compact, wherein magnetizing directions in the central portion and both side portions sandwiching the central portion are orthogonal to each other. A method of manufacturing a multi-magnetization unit permanent magnet.

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