JP2023094825A - Orientation device, manufacturing method for compact, magnetization device, manufacturing method for magnet, and air-core coil - Google Patents

Abstract

To provide an orientation device including an air-core coil that can generate a magnetic flux represented by a longer straight line in the air-core coil.SOLUTION: The orientation device includes an air-core coil and a cavity arranged in a position including a central axis ω of the air-core coil and filled with magnet powder. The orientation device is used to orient the magnet powder in the cavity. In a cross-section including the central axis ω, the air-core coil has a reduced diameter portion whose cross-sectional diameter becomes smaller toward an end in a direction parallel to the central axis ω.SELECTED DRAWING: Figure 1

Description

The present invention relates to an orienting device, a method for manufacturing a compact, a magnetizing device, a method for manufacturing a magnet, and an air-core coil.

Conventionally, when manufacturing a magnet, a cavity filled with raw material powder (magnet powder) is inserted into an air-core coil to generate a magnetic field, thereby aligning the orientation direction of the raw material powder.

As a conventional method related to this, for example, Patent Document 1 discloses a filling means for filling a cavity of a container with an alloy powder as a raw material of a sintered magnet, and applying a mechanical pressure to the alloy powder filled in the cavity. Orienting means for orienting the alloy powder by applying a magnetic field without applying mechanical pressure to the alloy powder oriented by the orienting means, and sintering for sintering the alloy powder by heating the alloy powder without applying mechanical pressure to the alloy powder oriented by the orienting means. a) an air-core coil; and b) the orienting means are arranged in the air-core coil on both open end sides of the air-core coil across a space for accommodating the container. and a ferromagnetic material comprising a ferromagnetic material.

Further, Patent Document 2 discloses a magnetizing device that magnetizes a magnet material by applying a high magnetic field. A magnetizing device is described in which the control member is located inside the magnetizing coil.

International Publication No. 2014/123078 JP 2004-221354 A

However, in the case of the conventional air-core coil, the range in which the magnetic flux advances straight is narrow. In this case, it may be difficult to linearly orient the raw material powder (magnet powder) in the cavity. In addition, when magnetizing a raw material powder that has been linearly oriented, it is sometimes difficult to magnetize it linearly.

An object of the present invention is to solve the above problems. That is, the present invention provides an air-core coil capable of generating a magnetic flux represented by a longer straight line in the air-core coil, an orienting device or a magnetizing device including the same, and a method for manufacturing a compact using them. and a method for manufacturing a magnet.

The present invention is the following (1) to (8).
(1) Orientation used for orienting the magnet powder in the cavity, including an air-core coil and a cavity that is arranged at a position that includes the central axis ω of the air-core coil and is filled with the magnet powder a device,
In a cross section including the central axis ω, the air-core coil has a diameter-reduced portion whose cross-sectional diameter becomes smaller toward an end in a direction parallel to the central axis ω.
(2) The alignment device according to (1), wherein the air-core coil has the diameter-reduced portions at both ends thereof in a direction parallel to the central axis ω.
(3) A method for producing a compact, comprising orienting the magnet powder in the cavity using the orienting device according to (1) or (2) above to obtain an oriented magnet compact.
(4) Magnetization for magnetizing the sintered body, comprising an air-core coil and a fixing means for fixing a sintered body obtained by sintering magnet powder to a position including the central axis ω of the air-core coil. a device,
A magnetizing device, wherein, in a cross section including the central axis ω, the air-core coil has a reduced-diameter portion whose cross-sectional diameter becomes smaller toward an end in a direction parallel to the central axis ω.
(5) The magnetizing device according to (4), wherein the air-core coil has the diameter-reduced portions at both ends in a direction parallel to the central axis ω.
(6) A method for manufacturing a magnet, comprising magnetizing the sintered body using the magnetizing device according to (4) or (5) above to obtain a magnet.
(7) An air-core coil included in an orienting device used for orienting magnet powder or a magnetizing device used for magnetizing a sintered body obtained by sintering the magnet powder,
An air-core coil having a diameter-reduced portion whose cross-sectional diameter becomes smaller toward an end parallel to the central axis ω in a cross section including the central axis ω.
(8) The air-core coil according to (7) above, which has the diameter-reduced portions at both ends in a direction parallel to the central axis ω.

INDUSTRIAL APPLICABILITY According to the present invention, an air-core coil capable of generating a magnetic flux represented by a longer straight line in the air-core coil, an orienting device or a magnetizing device including the same, and a method for manufacturing a compact using them and a method for manufacturing a magnet.

FIG. 1(a) is a schematic perspective view of the air-core coil 10 of the first aspect, and FIG. 1(b) includes the central axis ω of the air-core coil 10 of the air-core coil 10 and the cavity 1 of the first aspect. FIG. 1(c) is a simulation result showing a magnetic field generated when 3000 A is applied to the air-core coil 10 of the first embodiment shown in FIG. 1(a). FIG. 2(a) is a schematic perspective view of the air-core coil 20 of the second aspect, and FIG. 2(b) includes the center axis ω of the air-core coil 20 of the air-core coil 20 and the cavity 1 of the second aspect. FIG. 2(c) is a simulation result showing a magnetic field generated when 3000 A is applied to the air-core coil 20 of the first mode shown in FIG. 2(a). FIG. 3(a) is a schematic perspective view of the air-core coil 30 of the third embodiment, and FIG. 3(b) is a schematic side view of the air-core coil 30 of the third embodiment. FIG. 4(a) is a schematic perspective view of a conventionally known air-core coil 100, and FIG. 4(b) is a cross section of the conventionally known air-core coil 100 and a cavity 1 including the central axis ω of the air-core coil 100. FIG. 4(c) is a simulation result showing a magnetic field generated when 3000 A is applied to the conventionally known air-core coil 100 shown in FIG. 4(a). FIG. 4 is a diagram for explaining a simulation method (a diagram for explaining equations 1 and 2); It is a figure which shows the cross section containing the central axis of the air core coil assumed in simulation (it is a figure for description of the formula of several 3). It is a schematic diagram showing a cross section including a central axis ω of an air-core coil used in an example. FIG. 4 is a schematic diagram showing a cross section including the central axis ω of another air-core coil used in the example. It is a graph which shows the result of an Example.

The present invention will be described.
The present invention includes an air-core coil and a cavity that is arranged at a position that includes the central axis ω of the air-core coil and is filled with magnet powder, and is used to orient the magnet powder in the cavity. In the orienting device, in a cross section including the central axis ω, the air-core coil has a diameter-reduced portion whose cross-sectional diameter becomes smaller toward the end in the direction parallel to the central axis ω.
Such an alignment device is hereinafter also referred to as "the alignment device of the present invention".

Further, the present invention is a method for producing a compact, comprising orienting the magnet powder in the cavity using the orienting apparatus of the present invention to obtain an oriented magnet compact.
Such a manufacturing method is hereinafter also referred to as a "method for manufacturing a molded article of the present invention".

Further, the present invention includes an air-core coil, and a fixing means for fixing a sintered body obtained by sintering magnet powder to a position including the central axis ω of the air-core coil to magnetize the sintered body. wherein, in a cross section including the central axis ω, the air-core coil has a diameter-reduced portion whose cross-sectional diameter becomes smaller toward the end in the direction parallel to the central axis ω. .
Such a magnetizing device is hereinafter also referred to as "the magnetizing device of the present invention".

The present invention also provides a method for manufacturing a magnet, comprising magnetizing the sintered body using the magnetizing apparatus of the present invention to obtain a magnet.
Such a manufacturing method is hereinafter also referred to as the "manufacturing method of the magnet of the present invention".

The present invention also provides an air-core coil included in an orienting device used for orienting magnet powder or a magnetizing device used for magnetizing a sintered body obtained by sintering the magnet powder, wherein the central axis ω is The air-core coil has a diameter-reduced portion whose cross-sectional diameter becomes smaller toward the end in the direction parallel to the central axis ω.
Such an air-core coil is hereinafter also referred to as "the air-core coil of the present invention".

The orienting device of the present invention or the magnetizing device of the present invention includes the air-core coil of the present invention.

Hereinafter, when simply referred to as the "present invention", any of the orienting device of the present invention, the method of manufacturing a compact of the present invention, the magnetizing device of the present invention, the method of manufacturing a magnet of the present invention, and the air-core coil of the present invention. shall also mean

The air-core coil and cavity of the orienting device of the present invention will be described with reference to the drawings. This air core coil corresponds to the air core coil of the present invention.

The air-core coils and cavities shown in the following figures are examples, and the air-core coils and cavities in the present invention are not limited to the embodiments shown in the figures.

FIG. 1(a) shows a schematic perspective view of the air-core coil 10 of the first embodiment.
Moreover, FIG. 1(b) shows the contents of the orienting device 2 according to the first aspect, and shows a schematic cross section of the air-core coil 10 and the cavity 1 of the first aspect including the central axis ω of the air-core coil 10. It is a diagram. That is, FIG. 1(b) is a schematic diagram showing a cross section obtained when the air-core coil 10 and the cavity 1 of the first mode are cut along a plane including the central axis ω of the air-core coil 10 . The cavity 1 shown in FIG. 1 is the same as the cavity 1 shown in FIGS. 2 to 4, which will be described later.
Further, FIG. 1(c) is a simulation result showing a magnetic field generated when 3000 A is applied to the air-core coil 10 of the first mode shown in FIG. 1(a). FIG. 1(c) shows magnetic lines of force in a cross section obtained by cutting along a plane including the central axis ω of the air-core coil 10 as in FIG. 1(b). 1 is shown.
A simulation method will be described later.

In the cross section including the central axis ω shown in FIG. 1B, the air-core coil 10 of the first mode has a cross-sectional diameter (a diameter of the air-core coil in a cross section perpendicular to the central axis ω) toward the end parallel to the central axis ω. It has diameter-reduced portions 12 and 14 at both ends in the same direction. That is, the air-core coil 10 of the mode shown in FIG. 1 has a diameter-reduced portion 12 and a diameter-reduced portion 14 at both ends in the direction parallel to the central axis ω, and these are connected by a portion 16 that does not correspond to the diameter-reduced portion. In the embodiment shown in FIG. 1, this portion 16 has a constant cross-sectional diameter.

FIG. 2(a) shows a schematic perspective view of the air-core coil 20 of the second mode.
FIG. 2(b) is a schematic diagram showing a cross section of the air-core coil 20 and the cavity 1 of the second mode, including the central axis ω of the air-core coil 20. As shown in FIG. That is, FIG. 2B is a schematic diagram showing a cross section obtained when the air-core coil 20 and the cavity 1 of the second embodiment are cut along a plane including the central axis ω of the air-core coil 20 .
Further, FIG. 2(c) is a simulation result showing the magnetic field generated when 3000 A is applied to the air-core coil 20 of the second mode shown in FIG. 2(a). FIG. 2(c) shows magnetic lines of force in a cross section obtained by cutting along a plane including the central axis ω of the air-core coil 20 as in FIG. 2(b). 1 is shown.
A simulation method will be described later.

The air-core coil 20 of the second embodiment has diameter-reduced portions 22 and 24 whose cross-sectional diameters become smaller toward the ends in the direction parallel to the central axis ω in the cross section including the central axis ω shown in FIG. 2(b). there is Moreover, unlike the case of the above-mentioned 1st aspect, it does not have a part other than that. In other words, the air-core coil 20 of the embodiment shown in FIG. 2 is an embodiment in which the diameter-reduced portion 22 and the diameter-reduced portion 24 are coupled.

FIG. 3(a) shows a schematic perspective view of the air-core coil 30 of the third embodiment. FIG. 3(b) is a schematic diagram showing a side surface of the air-core coil 30 of the first mode.

The air-core coil 30 of the third aspect has, on the side surface shown in FIG. It has further parts 36, 38 on the sides. In the embodiment shown in FIG. 3, the two reduced diameter sections 32, 34 are adjacent and have portions 36, 38 of constant cross-sectional diameter at opposite ends of each.

The embodiment shown in FIG. 4 does not correspond to the present invention.
FIG. 4A shows a schematic perspective view of a conventionally known air-core coil 100. FIG.
FIG. 4B is a schematic diagram showing a cross section of the conventionally known air core coil 100 and the cavity 1 including the central axis ω of the air core coil 100 . That is, FIG. 4B is a schematic diagram showing a cross section obtained by cutting the conventionally known air-core coil 100 and the cavity 1 along a plane including the central axis ω of the air-core coil 100 .
Further, FIG. 4(c) is a simulation result showing a magnetic field generated when 3000 A is applied to the conventionally known air-core coil 100 shown in FIG. 4(a). FIG. 4(c) shows magnetic lines of force in a cross section obtained by cutting along a plane including the central axis ω of the air-core coil 40 as in FIG. 4(b). 1 is shown.
A simulation method will be described later.

The conventionally known air core coil 100 shown in FIG. 4 does not have the reduced diameter portion that the embodiments shown in FIGS. 1 to 3 have.

Comparing FIG. 1(c), FIG. 2(c) and FIG. 4(c), in the case of FIG. 1(c) and FIG. 2(c), the air-core coil It can be confirmed that the magnetic flux represented by a longer straight line can be generated inside.

A method of simulation performed to create FIGS. 1(c), 2(c) and 4(c) will be described.
As shown in FIG. 5, the magnetic field (H) created by the minute portion (dl) on the coil at the position of the coordinate X of the central axis ω (with the center of the coil as a reference (zero)) is expressed by the following Biot-Savart equation: can be represented.

Here, I means the energized current and a means the radius of the coil.

Extending this to one round of the coil, the magnetic field generated by one coil at the position of the coordinate X of the central axis ω can be expressed by the following equation.

Then, the coil shown in FIG. 6 is assumed. In the coil shown in FIG. 6, a plurality of circular coils are arranged coaxially (on the center axis) and are bilaterally symmetrical and vertically symmetrical. The origin (zero point) is the center of the coil on the central axis and in a direction parallel to the central axis. The number of coil turns to the right from the coil center (origin) is m, and the number of coil turns to the left is -m. Also, n means the n-th coil counted from the origin.
Then, the magnetic field created at the coordinate X of the central axis ω can be expressed by the following equation.

This formula is also referred to as formula A below.

Then, using this formula, change the coil diameter (R(x)) at each position (x) to calculate the change in the magnetic field on the coil center axis, and find the coil shape ( Investigate the coil shape that reduces the change in H(x). After that, a simulation with that shape is performed, and FIGS. 1(c), 2(c) and 4(c) showing the flow of the magnetic flux in the cross section of the coil when the coil is energized with 3000 A are obtained.
As a simulator, MAGNUM (manufactured by Field Precision LLC, USA), which is a general-purpose simulator based on the finite element method, was used.

In the air-core coils of the first to third modes shown in FIGS. 1 to 3, ring-shaped square pipes made of copper (each side is 8 mm) are arranged in four layers in the radial direction, and are arranged parallel to the central axis ω and It is arranged so as to be in contact with this in the vertical direction.
However, in the present invention, the material of the air core coil may be other than copper, the cross section may not be rectangular, the pipe may not be used, and the number of coils arranged in the radial direction is not limited.

Although the length of the reduced diameter portion in the direction parallel to the central axis ω is not particularly limited, it is preferably 150 to 330 mm, more preferably 180 to 270 mm.

The existence ratio of the diameter-reduced portions in the direction parallel to the central axis ω, that is, the length of the diameter-reduced portions relative to the length of the air-core coil in the direction parallel to the central axis ω (if there are multiple diameter-reduced portions, the total length Although the ratio (percentage) of ) is not particularly limited, it is preferably 30 to 90%, more preferably 30 to 80%.

The reduced-diameter portion is a part of the air-core coil, and in a cross section including the central axis ω of the air-core coil, the cross-sectional diameter of the portion decreases toward the end in the direction parallel to the central axis ω. The degree is not particularly limited. For example, the ratio (percentage) of the smallest cross-sectional diameter to the largest cross-sectional diameter is preferably 40-80%, more preferably 50-70%.
Here, when the reduced-diameter portions are arranged overlapping in the radial direction as in the embodiment shown in FIGS. The diameter shall be determined by the center of the ring of

The cross-sectional diameter of the end opening in the direction parallel to the central axis ω of the air core coil is preferably 90 to 200 mm, more preferably 200 to 110 mm.
Also, the cross-sectional diameter of the portion other than the opening is preferably 190 to 320 mm.
Here, when the air-core coils are arranged overlapping in the radial direction as in the embodiment shown in FIGS. The cross-sectional diameter is the diameter determined by the center of the ring.

The cavity 1 shown in FIGS. 1 to 3 is not particularly limited as long as it can be filled with magnet powder, and may be, for example, a conventionally known cavity. The cavity is arranged inside the air-core coil at a position including the central axis ω, as in the conventional art.
Further, as in the embodiments shown in FIGS. 1 to 3, it is preferable that the center of the magnet powder filled in the cavity is arranged on the central axis ω.

The magnet powder used here may be any one that can be processed to align the orientation directions by inserting a cavity filled with the powder into an air-core coil and generating a magnetic field.
As the magnet powder, an RTB-based magnet powder can be used. The RTB system means that the main components are rare earth elements (R), transition elements (T) and boron (B), and the rare earth elements include Nd, Pr, Dy, Tb, etc., transition elements Examples include Fe, Co, Ni, and the like.
Magnet powder can be obtained, for example, by injecting a melted mother alloy onto a rotating roll, super-quenching it to obtain a ribbon having a fine crystal structure, and pulverizing this ribbon to a size of about 150 μm or less. can be done.

In the cross section including the central axis ω shown in FIGS. 1B and 2B, it is preferable to have a soft magnetic body 3 as a yoke outside the cavity 1 in the direction parallel to the central axis ω. This serves to straighten the magnetic flux at low magnetic fields.
The soft magnetic material 3 as a yoke may be, for example, a silicon steel plate.

The parts other than the air-core coil and the cavity in the orienting device of the present invention may be the same as conventionally known orienting devices used for orienting the magnet powder in the cavity.

By applying a magnetic field to the magnet powder in the cavity using the orientation device of the present invention as described above, orientation is performed to align the direction of the magnetization easy axis of the magnet powder in a desired direction, and an oriented magnet compact is obtained. can be obtained by the method for producing a molded article of the present invention.
In the present invention, magnetic flux represented by a longer straight line can be generated in the air-core coil. The entire magnet powder filled therein can be oriented in a desired direction (parallel to the central axis ω).

Parts other than the air-core coil in the magnetizing device of the present invention may be the same as those of conventionally known magnetizing devices.
For example, after sintering an oriented magnet compact obtained by the method for producing a compact of the present invention, and fixing the obtained sintered compact at a position including the central axis ω of the air-core coil by a conventionally known fixing means. , the sintered body can be magnetized.
Here, the fixing means can be realized by a jig (not shown) for holding the soft magnetic body 3 toward the inside of the cavity 1 in FIG. 1(b).
Further, for example, when stacking storage cases capable of accommodating a plurality of plate-shaped magnets in the cavity shown in FIG.

The method for producing a magnet of the present invention can be performed by applying a magnetic field to the sintered body using the magnetizing apparatus of the present invention as described above to magnetize the sintered body and obtain a magnet.
For example, the oriented magnet molded article obtained by the method for manufacturing the molded article of the present invention is linearly oriented in a wider range. According to this, it is possible to linearly magnetize the wide range.

An air-core coil similar to that shown in FIG. 2 was prepared. It is shown in FIG.
However, in the air-core coil of the embodiment shown in FIG. 7, ring-shaped square pipes made of copper (each side is 8 mm) are arranged in four layers in the radial direction so as to be in contact with the central axis ω in the direction parallel to and perpendicular to it. It is placed in
Here, in the R (radius)-Z (height) coordinate system of the air-core coil shown in FIG. 7, the center of the air-core coil is the origin.
Then, when the radius of the air-core coil is shifted by 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm for every 8 mm shift in the Z (height) direction, in the above formula A,
(μ0・H(z))/(μ0・H(0))＝(H(z)/H(0))＝z
The magnetic flux density at the coordinate position of /the magnetic flux density at the origin position was calculated.
Note that the variable x was replaced with z in accordance with the coordinate system.

In addition, similar calculations were also performed for the case where the radius of the air-core coil was not changed (when shifted by 0 mm). This corresponds to the air-core coil shown in FIG.

Furthermore, an air-core coil similar to that shown in FIG. 3 was prepared. It is shown in FIG.
However, in the air-core coil of the embodiment shown in FIG. 8, ring-shaped copper square pipes (one side is 4 mm) are arranged in four layers in the radial direction, and are arranged so as to be in contact with the central axis ω in a direction parallel to and perpendicular to it. It is placed in
In this case, the coil inner diameter is individually adjusted at each height position (Z direction), and in the above equation A,
(μ0・H(z))/(μ0・H(0))＝(H(z)/H(0))＝z
The magnetic flux density at the coordinate position of /the magnetic flux density at the origin position was calculated.
Note that the variable x was replaced with z in accordance with the coordinate system.
Further adjustments were made to reduce this value.

The results are shown in FIG. In addition, in FIG. 9, the case of the mode shown in FIG. 8 is indicated as "appropriate".

As shown in FIG. 9, in the case of 0 mm, that is, in the case of a conventionally known air-core coil corresponding to FIG. ” decreased to about 95%.
On the other hand, in the case of “1 to 6 mm” and “appropriate”, the “magnetic flux density/magnetic flux density at the origin position” decreases to about 95% more than 35 mm. In particular, in the case of 4 mm or more, the "magnetic flux density/magnetic flux density at the origin position" decreases to about 95%, which is expanded to about 50 mm, which is preferable.

From these results, it can be said that the present invention can generate a magnetic flux represented by a longer straight line in the air-core coil.

REFERENCE SIGNS LIST 1 cavity 2 orientation device 3 soft magnetic body (yoke)
12, 14, 22, 24, 32, 34 Reduced diameter portion 16, 36, 38 Other than reduced diameter portion 10 Air core coil of first aspect 20 Air core coil of second aspect 30 Air core coil of third aspect 100 Conventionally known air-core coil ω center axis of air-core coil

Claims (8)

An orienting device used for orienting the magnet powder in the cavity, comprising an air-core coil and a cavity that is arranged at a position that includes the central axis ω of the air-core coil and is filled with the magnet powder. hand,
In a cross section including the central axis ω, the air-core coil has a diameter-reduced portion whose cross-sectional diameter becomes smaller toward an end in a direction parallel to the central axis ω. 2. The orientation device according to claim 1, wherein said air-core coil has said reduced-diameter portions at both ends thereof in a direction parallel to said central axis ω. 3. A method for producing a compact, comprising orienting the magnet powder in the cavity using the orienting device according to claim 1 or 2 to obtain an oriented magnet compact. A magnetizing device for magnetizing the fired body, comprising: an air-core coil; hand,
A magnetizing device, wherein, in a cross section including the central axis ω, the air-core coil has a reduced-diameter portion whose cross-sectional diameter becomes smaller toward an end in a direction parallel to the central axis ω. 5. The magnetizing device according to claim 4, wherein said air-core coil has said reduced-diameter portions at both ends thereof in a direction parallel to said central axis ω. 6. A method for manufacturing a magnet, comprising magnetizing the sintered body using the magnetizing device according to claim 4 or 5 to obtain a magnet. An air-core coil included in an orienting device used for orienting magnet powder or a magnetizing device used for magnetizing a sintered body obtained by sintering the magnet powder,
An air-core coil having a diameter-reduced portion whose cross-sectional diameter becomes smaller toward the end in a direction parallel to the central axis ω in a cross section including the central axis ω. 8. The air-core coil according to claim 7, wherein the diameter-reduced portions are provided at both ends in a direction parallel to the central axis ω.

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