JP2000353632A - Magnetic field application apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mass-produce superior magnetic molded elements with reduced electric power by relative moving a receptacle containing magnetic anisotropic powder into the inside of a producing part which causes magnetic field gradient to be produced a superconducting coil. SOLUTION: This magnetic field application apparatus is provided with a punch rod 53, which vertically extends and whose upper end is connected to a mold support portion 51, and a mold support portion 51 in disc form which supports the lower edge of a mold 3 as receptacle containing magnetic powder 2. The lower end of the punch rod 53 is connected to the lower ram on the press side and the mold 3 is put into and taken out from a steady magnetic field generating portion 4 by vertically moving the punch rod 53. By moving the magnetic power 2 from the place far from a superconducting coil 7 toward its central part, since the grains of the anisotropic magnetic powder 2 pass through the points where the magnetic field gradient is large, they are placed in the central part of the superconducting coil 7, while being oriented along the lines of magnetic flux. The magnetic powder 2 is pressed by upper and lower punches 6 and 5 in the center of the coil where they are oriented and is fixed to form a magnetic molded element, in such a way that the orientation of the magnetic powder is not lost. The magnetic molded element is moved in the magnetic field and is taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying a magnetic powder to a stationary magnetic field generating section such as a superconducting magnet, for example, to a magnetic field application apparatus such as a permanent magnet powder molding apparatus.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional magnetic field application apparatus disclosed in Japanese Patent Application Laid-Open No. 9-313229. This magnetic field application apparatus is applied to powder molding of a permanent magnet. The permanent magnet is formed by compression molding the magnetic powder 102 held in the mold 101 by the upper and lower punches 105 and 106 provided on the upper and lower beds 103 and 104. Since the individual grains of the magnetic powder 102 have magnetic anisotropy, it is necessary to make the anisotropy of the individual grains of the magnetic powder 102 uniform, that is, to orient them in order to improve the properties of the permanent magnet. In order to orient the magnetic powder 102, a magnetic field generating unit 107 constituted by an electromagnetic coil is conventionally provided so as to surround the mold 101.

That is, a magnetic powder 102 is introduced into a mold 101, and a magnetic field of about 1.5 T is generated in a state where the magnetic powder 102 is installed near the center of a magnetic field generating unit 107. Are oriented along the magnetic flux lines. Moreover,
The compression molding was performed by the lower punches 105 and 106, and at the stage when the molding was completed, the magnetic field was reduced and the magnetic molded body was taken out.

[0004]

However, in the case of a conventional magnetic field application apparatus, the magnetic powder 102 is transferred to the magnetic field generator 107.
Since the magnetic field was applied after installing at the predetermined position of
The electromagnetic force applied to the magnetic powder 102 is small,
There was a limit in improving the orientation of No. 2.

Generally, a normal conducting coil is used for the magnetic field generating unit 107, and it takes an exciting time for generating a magnetic field. Also, a high voltage and high current type excitation power source is required, and power consumption is large, and the generated magnetic field is limited to about 2T. It is also conceivable to generate a steady magnetic field in order to eliminate the excitation time, but it is difficult to remove the magnetic compact formed while the electromagnetic force is acting.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a magnetic field application apparatus capable of mass-producing a magnetic compact having good magnetic properties with low power consumption. Another object of the present invention is to provide a magnetic field application device capable of easily removing a magnetic molded body from a magnetic field generating unit.

[0007]

In order to achieve the above object, the invention according to claim 1 is directed to a container for storing magnetic powder having magnetic anisotropy, and a magnetic field generation for generating a magnetic field gradient by a superconducting coil. And a moving mechanism for relatively moving the container into the magnetic field generating unit.

[0008] The invention according to claim 2 is provided with a punch for pressing the magnetic powder in the container oriented inside the magnetic field generating unit.

According to a third aspect of the present invention, there is provided a stationary magnetic field generating section for generating a magnetic field gradient by a superconducting coil, a magnetic shield provided around the stationary magnetic field generating section, and A moving mechanism for moving the placed magnetic molded body having magnetism from inside the stationary magnetic field generating section to outside the magnetic shield.

According to a fourth aspect of the present invention, there is provided a container for storing a magnetic powder having magnetic anisotropy, a stationary magnetic field generating section having a superconducting coil while generating a magnetic field gradient,
A magnetic shield provided around the stationary magnetic field generating unit, a punch for compacting a magnetic powder in the container inside the stationary magnetic field generating unit to form a magnetic molded body, and And a moving mechanism for relatively moving the magnetic molded body from inside the stationary magnetic field generating unit to outside the magnetic shield.

Further, in the invention according to claim 5, a demagnetizing coil for demagnetizing the magnetic molded body is arranged on the magnetic shield.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. Embodiment 1 FIG. FIG. 1 shows a magnetic field application apparatus according to Embodiment 1 of the present invention. In this embodiment, as in the conventional example, a magnetic field application device is applied to a permanent magnet powder molding device.

That is, the magnetic field application apparatus 1 comprises a mold 3 as a container for storing a magnetic powder 2 having anisotropy of magnetization, and a stationary magnetic field generator 4 for generating a stationary magnetic field gradient without excitation time. And a lower punch 5 that constitutes a moving mechanism that supports the mold 3 and moves the inside of the stationary magnetic field generator 4 through the magnetic field gradient. The mold 3 has a space 31 filled with the magnetic powder 2. The lower punch 5 is used as a punch for compressing and solidifying the magnetic powder 2 in the space 31 from above and below. An upper punch 6 facing the lower punch 5 is provided. The upper punch 6 is driven by an upper ram (not shown) of the press, and the lower punch 5 is driven by a lower ram (not shown) or another drive mechanism provided on the press.

The lower punch 5 has a disk-shaped mold support portion 51 for supporting the lower end surface of the mold 3, and is inserted into the lower end opening of the space 31 of the mold 3 and is provided on the upper surface of the mold support portion 51. It has a disc-shaped lower punch tip 52 to be mounted, and a punch rod 53 extending vertically and having an upper end connected to the mold support 51. The lower end of the punch rod 53 is connected to a lower ram on the press side (not shown) or another driving device, and the die 3 is moved in and out of the stationary magnetic field generator 4 by moving the punch rod 53 in the vertical direction. Has become. In this sense, the punch rod 53 of the lower punch 5 and the mold support 51 constitute a moving mechanism. However, the stationary magnetic field generating section 4 is moved so that the mold 3 is moved to the stationary magnetic field generating section 4.
You may make it put in and out. In that case,
A moving mechanism for moving the stationary magnetic field generator 4 may be separately provided.

The stationary magnetic field generator 4 includes a superconducting coil 7,
A vacuum vessel 8 containing the superconducting coil 7, a heat insulating support 9 for supporting the superconducting coil 7 in the vacuum vessel 8, and a refrigerator 10 as a cooling means for cooling the superconducting coil 7 are provided. The vacuum vessel 8 has a ring shape having a room temperature bore 11 for utilizing a magnetic field space, and has a cylindrical outer peripheral wall 81;
It is composed of an upper end wall 82, a lower end wall 83, and a cylindrical inner peripheral wall 84 surrounding the room temperature bore 11. The mold 3 is put into and taken out of the room temperature bore 11 by the lower punch 5.

The superconducting coil 7 is a ring-shaped solenoid coil, which is disposed so as to surround the room temperature bore 11 via an inner peripheral wall 84, and a coil supporting member 71 for supporting the superconducting coil 7 is separated from the upper end wall 82 by the heat insulating supporting member 9. Hanged. Various materials can be used as the superconducting coil 7. For example, the superconducting coil 7 is wound by an NbTi (niobium titanium alloy) superconducting wire, and is configured to constantly generate a high magnetic field of 5 T at the coil center. For example, if the inner diameter of the coil is 400 mm and the axial length is 300 mm, the maximum magnetic field gradient on the central axis is about 200 T / m, and a very large magnetic field gradient is generated. And
The mold 3 inserted into the room temperature bore 11 of the vacuum container 8 by the lower punch 5 is inserted into the center of the superconducting coil 7.
The magnetic field gradient near the center of the superconducting coil 7 is small, for example, 1 T / m or less in the range of a 20 mm sphere.

For example, a small refrigerator of the Gifford McMahon type is used as the refrigerator 11, and the upper end wall 82 of the vacuum vessel 8 is used.
The superconducting coil 7 is installed on the upper surface and
And cooled to around minus 270 ° C. by heat transfer.

In this magnetic field application apparatus, attention is paid to one magnetic powder among the magnetic powders 2. The electromagnetic force F received by the magnetic moment M of the magnetic powder 2 in the magnetic field gradient is F = grad (MH). H is an external magnetic field. As can be seen from this equation, the electromagnetic force increases as the magnetic field gradient increases. As described above, the particles of the magnetic powder 2 having anisotropy are moved to the magnetic flux lines in FIG. It is arranged at the center of the superconducting coil 7 while being oriented along. In the vicinity of the center, the magnetic field gradient is small and the magnetic field distribution is uniform. In the case of a solenoid coil as shown in FIG.
The magnetic powder 2 disposed at the center of the above is similarly oriented in the axial direction. That is, when a magnetic field was applied after the magnetic powder was arranged at the center of the coil as in the related art, the magnetic powder 102 was hardly oriented because no magnetic field gradient was experienced.

If the magnetic powder 2 disposed at the center of the superconducting coil 7 is moved out of the magnetic field as it is, the orientation reverses due to the opposite phenomenon. Then, pressure molding is performed by the upper and lower punches 6 and 5 at the coil center where the magnetic powder 2 is oriented,
The magnetic powder 2 is pressed and fixed so that the orientation of the magnetic powder 2 is not lost. The magnetic molded body 21 which is the molded body fixed in this way.
Is moved and extracted in the magnetic field.

In the above configuration, the superconducting coil 7 is used for the stationary magnetic field generator 4. However, a water-cooled normal conducting coil has the same effect as the above embodiment. However, since the superconducting coil 7 is used for the stationary magnetic field generator 4, the power consumption of the coil is extremely small, and only the power of the small refrigerator is sufficient. Further, in the case of the superconducting coil 7, since it is easy to generate a generated magnetic field of 5T and 6T, it is possible to generate a large magnetic field gradient as described above. On the other hand, when the normal conducting coil is used, the power consumption is required to be two to five times that of the superconducting coil, including the power of water cooling. Further, it is considered that the generated magnetic field is limited to about 2T using an iron yoke. From this, the effect of using the superconducting coil 7 is great. Although it takes time, the superconducting coil may be excited only when the mold is moved into the magnetic field generating unit.

Embodiment 2 FIG. Hereinafter, a magnetic field application device according to a second embodiment of the present invention will be described with reference to the drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the second embodiment, the superconducting coil 7 shown in the first embodiment is used.
A magnetic shield 20 made of a ferromagnetic molded body is disposed around the periphery.

The magnetic shield 20 entirely covers the outer periphery of the outer peripheral wall 81, the upper end wall 82, and the lower end wall 83 of the vacuum vessel 8 with a ferromagnetic molded body having a predetermined thickness. Has been reduced. For example,
The surface magnetic field of the magnetic shield 20 made of soft iron having a thickness of 20 mm is as low as 0.005 T or less. As described above, since there is almost no magnetic field outside the magnetic shield 20, almost no electromagnetic force is generated in the magnetic molded body 21 by the magnetic field generated by the superconducting coil 7 as shown in FIG. Therefore, if the upper and lower punches 6 and 5 in FIG. 2 are made of a non-magnetic material, they can be easily removed together with the mold.

In the above configuration, the magnetic shield 2
Although a ferromagnetic material is used for 0, an effect similar to that of the above embodiment can be obtained by using an active shield coil that generates a magnetic field opposite to that of the superconducting coil 7.

Embodiment 3 FIG. Next, a magnetic field application device according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view showing a part of the magnetic field application device according to the third embodiment. In this embodiment, a demagnetizing coil 22 for demagnetizing the magnetic molded body 21 is provided near the take-out portion of the magnetic molded body 21 of the magnetic shield 20 according to the second embodiment. The second embodiment is the same as the second embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted.

The demagnetizing coil 22 is, for example, a superconducting coil 7.
A normal conducting coil that generates a magnetic field of 0.2 T, which is opposite to the above, is used. This magnetic field is generated only when the magnetic molded body 21 is taken out and passed. When the magnetic molded body 21 is taken out, the magnetic molded body 21 is demagnetized by the generation of the reverse magnetic field of the demagnetizing coil 22, and the generated magnetic field of the magnetic molded body 21 becomes almost zero. Since the magnetic molded body 21 is demagnetized, when the upper and lower punches 6 and 5 are made of a magnetic material, the magnetic molded body 21 is
5, the magnetic molded body 21 and the mold 3 can be easily taken out from the upper and lower punches 6 and 5. Further, even if the magnetic molded body 21 is taken out of the mold 3, it is not adsorbed to the surrounding magnetic material, so that the handling is easy. In the above configuration, a normal conducting coil is used as the demagnetizing coil 22, but a superconducting coil may be used, and the same effect as in the above embodiment can be obtained.

In the above configuration, the demagnetizing coil 22
Generates a reverse magnetic field only when the magnetic compact 21 is taken out, but may generate a steady reverse magnetic field in the same manner as the superconducting coil 7 having a steady magnetic field, and has the same effect as the above embodiment. . In this case, when the magnetic compact 21 is introduced into the center of the superconducting coil 7, a magnetic field in the opposite direction is once applied by the demagnetizing coil 7, so that all of the magnetic powder 2 rotates by 180 degrees or more. Therefore, there is also an effect that the orientation of the particles of the magnetic molded body 21 is improved.

[0027]

As described above, the invention according to claim 1 is
A container that stores magnetic powder having magnetic anisotropy, a magnetic field generating unit that generates a magnetic field gradient by a superconducting coil, and a moving mechanism that relatively moves the container into the magnetic field generating unit; Since the magnetic powder passes through the magnetic field gradient, there is an effect that the orientation of the magnetic powder is improved as compared with the conventional case where no magnetic field gradient is experienced. Further, since the superconducting coil consumes almost no power, a high magnetic field can be generated with low power consumption.

Further, the invention according to claim 2 is provided with a punch for compacting the magnetic powder in the container oriented inside the magnetic field generating section, so that the magnetic powder can be compacted in an oriented state. In addition, the orientation does not collapse even if it moves in a magnetic field gradient when it is taken out.

According to a third aspect of the present invention, there is provided a stationary magnetic field generating section having a superconducting coil while generating a magnetic field gradient, a magnetic shield provided around the stationary magnetic field generating section, A moving mechanism for moving the magnetic molded body having magnetism disposed inside from the inside of the stationary magnetic field generating unit to the outside of the magnetic shield, so that the magnetic molded body is removed after being arranged outside the shield by the moving mechanism That is, since the magnetic molded body is not affected by the electromagnetic force by the stationary magnetic field generating unit, there is an effect that it can be easily removed from the moving mechanism.

Further, the invention according to claim 4 is a container for accommodating magnetic powder having magnetic anisotropy, a stationary magnetic field generating section for generating a magnetic field gradient by a superconducting coil, and a stationary magnetic field generating section surrounding the stationary magnetic field generating section. A magnetic shield provided, a punch for compacting the magnetic powder in the container inside the stationary magnetic field generating unit to form a magnetic molded body, and moving the container relative to the stationary magnetic field generating unit and the magnetic material. A moving mechanism is provided to move the compact from the inside of the stationary magnetic field generation unit to outside the magnetic shield, so that the orientation of the magnetic powder can be improved and the compacted compact can be removed when the magnetic compact is removed. Since it is not affected by the electromagnetic force by the magnetic field generator, it can be easily removed from the moving mechanism.

In the invention according to claim 5, since the demagnetizing coil for demagnetizing the magnetic molded body is disposed on the magnetic shield, even if the member supporting the magnetic molded body is a magnetic material, Since no electromagnetic force is generated, not only can the magnetic member be easily removed from the moving member, but also the taken-out magnetic molded body does not stick to other magnetic materials, so that handling becomes easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnetic field application device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a magnetic field application device according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a part of a magnetic field application device according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional magnetic field application device.

[Explanation of symbols]

1 magnetic field application device, 2 magnetic powder, 3 mold (container),
4 Stationary magnetic field generator, 5 lower punch (moving mechanism), 51
Mold support, 52 lower punch tip, 53 punch rod, 6 upper punch, 7 superconducting coil, 8 vacuum vessel,
11 room temperature bore, 20 magnetic shield, 21 magnetic molded body, 22 demagnetizing coil.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Endo Politics 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Sumitomo Special Metals Co., Ltd. (72) Inventor Yuji Kaneko 2--15 Egawa, Shimamoto-cho, Mishima-gun, Osaka No. 17 Sumitomo Special Metals Co., Ltd. (72) Inventor Atsushi Ogawa 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka F-term in Sumitomo Special Metals Co., Ltd. 4K018 CA04 CA12 5E062 CC02 CE04 CE07 CF05

Claims (5)

[Claims] A container for storing magnetic powder having magnetic anisotropy; a magnetic field generating unit for generating a magnetic field gradient by a superconducting coil; and a moving mechanism for relatively moving the container into the magnetic field generating unit. A magnetic field application device in which the magnetic powder is oriented when the container is relatively moved. 2. The magnetic field application device according to claim 1, further comprising a punch for pressing the magnetic powder in the container oriented inside the magnetic field generating unit to form a magnetic compact. 3. A stationary magnetic field generator for generating a magnetic field gradient by a superconducting coil; a magnetic shield provided around the stationary magnetic field generator; and a magnetic powder disposed in the stationary magnetic field generator. A moving mechanism for moving the formed magnetic molded body from inside the magnetic field generating unit to outside the magnetic shield. 4. A container for storing magnetic powder having magnetic anisotropy, a stationary magnetic field generator for generating a magnetic field gradient by a superconducting coil, a magnetic shield provided around the stationary magnetic field generator, A punch for compacting the magnetic powder in the container inside the stationary magnetic field generating unit to form a magnetic molded body; and relatively moving the container into the stationary magnetic field generating unit and moving the magnetic molded body into the stationary magnetic field generating unit. A magnetic field application device comprising a moving mechanism for moving the magnetic shield from inside to outside the magnetic shield. 5. The magnetic field application device according to claim 3, wherein a demagnetizing coil for demagnetizing the magnetic molded body is disposed on the magnetic shield.