JP2005197594A - Method of manufacturing soft magnetic material, soft magnetic member, and cylindrical iron core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a soft magnetic material in which hysteresis loss is significantly reduced, and a soft magnetic member and a cylindrical iron core which are manufactured using the method. <P>SOLUTION: The method of manufacturing the soft magnetic material comprises steps of preparing a soft magnetic powder 11, and pressure molding the soft magnetic powder 11 in a magnetic field exceeding 8.0×10<SP>5</SP>(A/m) to form a compact. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a soft magnetic material, and a soft magnetic member and a cylindrical iron core manufactured using the method.

  Conventionally, it is known to produce electric and electronic parts such as a motor, a transformer, a transformer, a noise filter, and a choke coil using a soft magnetic material. For example, these electric and electronic parts can be produced by press-molding soft magnetic powder containing iron as a main component to form a molded body and subjecting the molded body to appropriate processing.

  In recent years, however, the density and size of electric and electronic parts have been increased, and more precise control is required with low power. In order to meet this requirement, it is necessary to reduce the hysteresis loss of the soft magnetic material used for electric and electronic parts, that is, to increase the magnetic permeability of the soft magnetic material and reduce the coercive force. A high-frequency dust core and a method of manufacturing the same for reducing the hysteresis loss in this way are disclosed in Japanese Patent Application Laid-Open No. 8-167518 (Patent Document 1).

According to the method for manufacturing a high-frequency powder magnetic core disclosed in Patent Document 1, a magnetic field generating coil generates a 1T (Tesla) magnetic field, and the shape-anisotropic soft magnet containing iron as a main component in the magnetic field. Press molding of the powder.
JP-A-8-167518

  However, soft magnetic powder containing iron as a main component originally has a lower magnetic permeability and a higher holding power than silicon steel plate materials and ferrite. For this reason, the present situation is that the high-frequency powder magnetic core disclosed in Patent Document 1 and the manufacturing method thereof have not sufficiently reduced the hysteresis loss.

  Accordingly, an object of the present invention is to solve the above-described problems, and provide a method of manufacturing a soft magnetic material in which hysteresis loss is sufficiently reduced, and a soft magnetic member and a cylindrical iron core manufactured using the method It is to be.

  The inventors have found that the magnetic permeability of the soft magnetic material can be increased and the coercive force can be reduced by orienting each of the soft magnetic particles that have been pressure-molded in the direction of the easy axis of magnetization.

  Based on this finding, the inventors have completed a method for producing a soft magnetic material according to the present invention, and a soft magnetic member and a cylindrical iron core produced using the method. The soft magnetic material referred to in the present specification is obtained not only by soft magnetic particles and soft magnetic molded products obtained by press molding soft magnetic particles, but also by, for example, extruding the soft magnetic molded products. Includes extruded materials.

The method for producing a soft magnetic material according to the present invention comprises a step of preparing soft magnetic particles and press-molding the soft magnetic particles in a magnetic field exceeding 8.0 × 10 ⁵ (A / m). Forming the step.

According to the method for producing a soft magnetic material configured as described above, each of the soft magnetic particles constituting the molded body can be oriented in the easy axis direction by utilizing the magnetocrystalline anisotropy. At this time, when the applied magnetic field is 8.0 × 10 ⁵ (A / m), that is, 10 (kOe: kilo-Oersted) or less, the influence of the magnetic field is too small to be oriented. Therefore, according to the present invention, it is possible to provide a soft magnetic material in which hysteresis loss is sufficiently reduced.

  Preferably, the step of forming the molded body includes a step of adding vibration to the soft magnetic particles. According to the method of manufacturing a soft magnetic material configured in this way, each of the soft magnetic particles can be easily oriented in the easy axis direction.

  Preferably, the magnetic field is formed by passing a current through the superconducting coil. According to the soft magnetic material manufacturing method configured as described above, a large magnetic field can be easily formed.

  Preferably, the superconducting coil is formed of a high temperature superconductor made of an oxide material. A high-temperature superconductor refers to one that exhibits superconductivity at a relatively high temperature of 30K or higher. According to the soft magnetic material manufacturing method configured as described above, the cooling device for the superconducting coil is simplified, so that the manufacturing cost of the soft magnetic material can be kept low.

  Preferably, the soft magnetic particles contain iron as a main component. Here, the soft magnetic particles indicate a case where 90 atomic% or more of iron is contained. According to the method of manufacturing a soft magnetic material configured as described above, a soft magnetic material having a high magnetic flux density can be obtained. Thereby, compared with the case where a ferrite material etc. are used, size reduction of the electrical / electronic component using a soft magnetic material can be achieved.

  Preferably, the soft magnetic particles are formed with an insulating coating surrounding the surface of the soft magnetic particles. According to the method of manufacturing a soft magnetic material configured as described above, it is possible to reduce loss due to eddy current flowing between the soft magnetic particles by insulating the soft magnetic particles. Further, the soft magnetic particles may be flat powder, and it is further preferable that the longitudinal direction of the flat powder and the easy magnetization axis direction are matched. By doing in this way, the effect by a magnetic field application can be heightened and orientation can be promoted.

  In the case where the insulating film is a non-magnetic material, further improvement of the magnetic characteristics can be expected by applying a magnetic field exceeding 10 (kOe). In addition, the molded body here includes those immediately after pressure molding and those having a product shape that has undergone processes such as cutting after pressure molding. It is also possible to prepare a plurality of the molded bodies and combine them in the direction along the magnetic circuit of the product.

  The soft magnetic member according to the present invention is a soft magnetic member produced by using any one of the above-described methods for producing a soft magnetic material. The soft magnetic member includes a plurality of portions oriented in the easy axis direction and combined with each other. Magnetic fields having different magnetic flux line directions are applied to each of the plurality of portions. The plurality of portions are combined so that the magnetic flux line direction of the applied magnetic field coincides with the easy magnetization axis.

  According to the soft magnetic member configured as described above, there is a portion where the magnetic flux line direction of the applied magnetic field and the easy magnetization axis do not coincide with each other, and the magnetic permeability can be prevented from decreasing at that portion. Thereby, it is possible to provide a soft magnetic member in which hysteresis loss is reduced.

  The cylindrical iron core according to the present invention is a cylindrical iron core manufactured by using the soft magnetic material manufacturing method described above. The cylindrical iron core is oriented in one direction along the easy axis of magnetization. The method for producing a soft magnetic material according to the present invention can be used for a cylindrical iron core in which the magnetic flux line direction of the applied magnetic field is one direction.

  As described above, according to the present invention, it is possible to provide a method of manufacturing a soft magnetic material in which hysteresis loss is sufficiently reduced, and a soft magnetic member and a cylindrical iron core manufactured using the method.

  Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a pressure molding apparatus used in the soft magnetic material manufacturing method according to Embodiment 1 of the present invention. Referring to FIG. 1, a pressure molding apparatus 1 includes a lower punch 19 and a mold part 17 facing each other, a side wall 15 that defines a space filled with soft magnetic powder 11 together with these parts, And a superconducting coil 13 provided so as to surround the wall 15.

  Hereinafter, a method of pressure-molding soft magnetic powder using the pressure-molding apparatus 1 in FIG. 1 will be described. First, soft magnetic powder 11 such as iron powder is produced by an atomizing method. Furthermore, an insulating film may be formed so as to cover the surface of the soft magnetic powder 11. Subsequently, the obtained soft magnetic powder is put into a predetermined space in the pressure molding apparatus 1. Then, a magnetic field exceeding 10 (kOe) is applied to the soft magnetic powder 11 by introducing a current into the superconducting coil 13. Next, with the magnetic field applied, the lower punch 19 is operated in the direction indicated by the arrow 20 to press-mold the soft magnetic powder 11.

  FIG. 2 is an enlarged schematic view showing the soft magnetic powder constituting the soft magnetic molded body in the soft magnetic molded body formed using the pressure molding apparatus in FIG. Referring to FIG. 2, each of the soft magnetic powders 11 is oriented along the easy magnetization axis 26. This is because the soft magnetic powder 11 is oriented in the direction of the easy magnetization axis 26 by the application of a magnetic field by the superconducting coil 13 and is pressure-molded at the same time. By setting the magnitude of the magnetic field to be applied to a value exceeding 10 (kOe), it is possible to obtain a soft magnetic molded body in such an oriented state.

The manufacturing method of the soft magnetic material according to the first embodiment of the present invention includes the step of preparing the soft magnetic powder 11 and the soft magnetic powder 11 in a magnetic field exceeding 8.0 × 10 ⁵ (A / m). And a step of forming a molded body by pressure molding. According to the method of manufacturing a soft magnetic material configured as described above, it is possible to optimize the magnetic characteristics (increase the magnetic permeability and reduce the coercive force) simultaneously with the pressure molding. For this reason, an electrical / electronic component with sufficiently reduced hysteresis loss can be produced by using the molded body obtained by this pressure molding.

  In the present embodiment, the soft magnetic powder 11 is pressure-formed while maintaining the state where the magnetic field is applied. However, after the magnetic field is applied and oriented for a predetermined period, the pressure-forming is performed. May be performed. In this case, the same effect can be obtained.

  FIG. 3 is a cross-sectional view showing another pressure molding apparatus used in the soft magnetic material manufacturing method according to Embodiment 1 of the present invention. Referring to FIG. 3, the pressure molding apparatus 31 basically has the same structure as that of the pressure molding apparatus 1 in FIG. 1, but includes a superconductor 33 built in the mold part 17. Further prepare.

  By providing the superconductor 33 in this way, the direction of the magnetic flux lines of the magnetic field applied by the superconducting coil 13 (the direction indicated by the arrow 35) is changed so as to be away from the superconductor 33 (Meissner effect). Further, by incorporating a permanent magnet or a coil in place of the superconductor 33, the direction of the magnetic flux lines can be changed in a predetermined direction.

(Embodiment 2)
FIG. 4 is a schematic diagram showing a soft magnetic member according to Embodiment 2 of the present invention. Referring to FIG. 4, soft magnetic member 41 is manufactured using the soft magnetic material manufacturing method described in the first embodiment.

  The soft magnetic member 41 is configured by combining a plurality of members 41a to 41e. The soft magnetic member 41 is used in a state where a magnetic field having different magnetic flux line directions (directions indicated by arrows 42) is applied to each of the plurality of members. Each of the plurality of members 41a to 41e is oriented in the easy magnetization axis direction (the direction along the line segment 43), and is combined so that the easy magnetization axis direction and the magnetic flux line direction coincide with each other.

  According to the soft magnetic member 41 configured as described above, it is possible to prevent an increase in hysteresis loss by eliminating a portion where the magnetic permeability is lowered.

(Embodiment 3)
FIG. 5 is a perspective view showing a cylindrical magnetic core according to Embodiment 3 of the present invention. Referring to FIG. 5, cylindrical magnetic core 51 is manufactured using the soft magnetic material manufacturing method described in the first embodiment.

  The cylindrical magnetic core 51 is used in a state where the coil 52 is turned on the outer periphery. The cylindrical magnetic core 51 is oriented in the easy magnetization axis direction (the direction indicated by the arrow 53), and the easy magnetization axis direction is the direction of the magnetic flux lines of the magnetic field generated in the cylindrical magnetic core 51 when a current is passed through the coil 52. Match.

  As described above, the method for producing a soft magnetic material according to the present invention can be easily used for a simple electric / electronic component in which the magnetic flux line direction of the applied magnetic field is one direction.

  In order to confirm the effect of the manufacturing method of the soft magnetic material described in the first embodiment, the verification shown in Table 1 below was performed.

  Referring to Table 1, a soft magnetic molded body according to the soft magnetic material manufacturing method described in the first embodiment and a soft magnetic molded body of a comparative example were manufactured. Next, the magnetic properties (magnetic flux density B100, magnetic permeability and coercivity when a magnetic field of 100 (Oe) was applied) of the produced soft magnetic molded body were measured. As a result of the measurement, B100 and the magnetic permeability increased and the coercive force decreased in all the soft magnetic molded bodies according to Embodiment 1 as compared with the soft magnetic molded body of the comparative example. From this, it was confirmed that according to the present invention, the hysteresis loss can be sufficiently reduced.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing which shows the pressure molding apparatus used for the manufacturing method of the soft-magnetic material in Embodiment 1 of this invention. FIG. 2 is an enlarged schematic view showing a soft magnetic powder constituting the soft magnetic molded body in the soft magnetic molded body formed using the pressure molding apparatus in FIG. 1. It is sectional drawing which shows another pressure molding apparatus used for the manufacturing method of the soft-magnetic material in Embodiment 1 of this invention. It is a schematic diagram which shows the soft-magnetic member in Embodiment 2 of this invention. It is a perspective view which shows the cylindrical magnetic core in Embodiment 3 of this invention.

Explanation of symbols

  11 soft magnetic powder, 41 soft magnetic member, 41a, 41b, 41c, 41d, 41e member, 51 cylindrical magnetic core.

Claims (7)

Preparing soft magnetic particles;
And a step of pressure-molding the soft magnetic particles to form a molded body in a magnetic field exceeding 8.0 × 10 ⁵ (A / m).   The method for producing a soft magnetic material according to claim 1, wherein a magnetic field is formed by passing a current through the superconducting coil.   The method of manufacturing a soft magnetic material according to claim 2, wherein the superconducting coil is formed of a high-temperature superconductor made of an oxide material.   The method for producing a soft magnetic material according to any one of claims 1 to 3, wherein the soft magnetic particles contain iron as a main component.   5. The method for producing a soft magnetic material according to claim 1, wherein the soft magnetic particles are formed with an insulating film surrounding a surface of the soft magnetic particles. 6. A soft magnetic member produced using the method for producing a soft magnetic material according to any one of claims 1 to 5,
A plurality of portions oriented in the direction of the easy axis of magnetization and combined with each other;
A magnetic field having a different magnetic flux line direction is applied to each of the plurality of portions, and the plurality of portions are combined so that the magnetic flux line direction of the applied magnetic field coincides with the easy magnetization axis. Soft magnetic member.   A cylindrical iron core produced by using the method for producing a soft magnetic material according to any one of claims 1 to 5, and oriented in one direction along an easy axis of magnetization.

Images