JP2003303727A - Method of manufacturing magnetic core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a magnetic core which secures insulation between amorphous alloy thin belts by a simple and low-cost method without reducing a space factor, and which has only small deterioration in core loss characteristic even if an outer surface is coated with a coating film such as resin. <P>SOLUTION: The method of manufacturing the magnetic core includes a process of spreading dispersed liquid, wherein particles of an average grain diameter of 500 nm or less are dispersed, between the amorphous alloy thin belts of the magnetic core before coating the outer surface of the magnetic core with the coating film. Since the specific dispersed liquid is spread between the amorphous alloy thin belts of the magnetic core before coating the outer surface of the magnetic core with the coating film, the magnetic core can be provided with a superior property, that is, small deterioration in core loss characteristic while retaining the space factor, as compared with a magnetic core manufactured by a conventional method wherein the dispersed liquid is not spread between the amorphous alloy thin belts of the magnetic core. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic core composed of an amorphous alloy ribbon having an outer surface coated with a coating film, and more particularly to a magnetic core having improved core loss characteristics. Manufacturing method.

[0002]

2. Description of the Related Art Amorphous alloys are amorphous solids produced by rapidly cooling from a molten state using iron, boron, silicon, etc. as raw materials, and usually have a thickness of about 0.01-
It can be obtained as a ribbon of about 0.1 mm. Amorphous alloy has a random structure with no regular arrangement of atoms, and has excellent characteristics as a soft magnetic material, such as high magnetic permeability, small coercive force, and a wide frequency range corresponding to a wide range of frequencies. is doing. Also, energy loss (hysteresis loss) when the magnetic flux passes.
Since the thickness of the ribbon is smaller than that of the silicon steel strip, the core loss (sum of hysteresis loss and eddy current loss) can be reduced. For this reason, magnetic cores manufactured by laminating amorphous alloy ribbons are used in many electric and electronic devices as transformers, etc. by utilizing their excellent characteristics. It also contributes greatly to weight reduction. Further, from the viewpoint of energy saving, a transformer using an amorphous iron core, which is one of the magnetic cores, has been attracting much attention in recent years.

A magnetic core using an amorphous alloy is generally manufactured as follows. First, a precursor of a magnetic core having a predetermined shape is prepared by a method of winding or superposing an amorphous alloy ribbon. Next, a predetermined annealing heat treatment is performed to develop a specific magnetic property. The conditions of the annealing heat treatment differ depending on the magnetic characteristics to be expressed, but the temperature is generally 330 ° C in an inert atmosphere.
Generally, it is performed at about 440 ° C. for about 0.1 to 100 hours at high temperature for a long time.

A conductor wire is wound around the magnetic core manufactured as described above in a coil shape and used as a component such as a transformer. In order to insulate the magnetic core from the conductor wire, thermosetting resin such as epoxy resin is used. A method of coating the outer surface of the magnetic core with a resin by powder electrostatic coating or the like is generally used. However, the formed coating film reduces the insulation between the amorphous alloy ribbons that make up the magnetic core, and affects the eddy current loss, especially in the high frequency region, reducing core loss characteristics. I have a problem to do.

As a method for solving this problem, a method of forming an insulating film of an inorganic oxide on the surface of the ribbon (Japanese Patent Laid-Open No. 61-10212), a heat-resistant insulating film such as a polyimide film, etc. Method (Japanese Patent Laid-Open No. 01-3
08013) is disclosed. However, in the former case, it is necessary to form an insulating coating by a special method, which not only complicates the process but also raises the problem of high cost. In the latter case, a film having a thickness of at least 5 to 10 μm is used, and the space factor, which is substantially the proportion of the alloy portion in the magnetic core, is significantly reduced as compared with the case where the film is not used. , There is a problem that affects the function as a magnetic core.

[0006]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide an insulating property between amorphous alloy ribbons by a simple and inexpensive method without lowering the space factor. Another object of the present invention is to provide a method of manufacturing a magnetic core in which the core loss characteristic is less reduced even when the outer surface is coated with a coating film of resin or the like.

[0007]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have studied the outer surface of a magnetic core in a method for producing a magnetic core having the outer surface covered with a coating film. The present invention has been completed by discovering that reduction of core loss characteristics can be suppressed by impregnating a magnetic core with a dispersion liquid in which particles having an average particle diameter of 500 nm or less are dispersed before coating with a covering film.

That is, the present invention provides the following [1] to
It is specified by the items described in [7].

[1] In a method for producing a magnetic core composed of an amorphous alloy ribbon having an outer surface coated with a coating film, an average particle diameter of 5 is obtained before coating the outer surface with the coating film.
A method for producing a magnetic core, comprising impregnating a dispersion liquid in which particles having a diameter of 00 nanometer or less are dispersed between the amorphous alloy ribbons of the magnetic core.

[2] The method for producing a magnetic core according to [1], wherein the dispersion is a colloidal inorganic oxide dispersion.

[3] The dispersion medium is an organic solvent [2]
The colloidal inorganic oxide dispersion described.

[4] The method for producing a magnetic core according to [1], wherein the dispersion is an organic emulsion.

[5] The magnetic core before being subjected to the annealing heat treatment is impregnated with the dispersion liquid, then the resin composition containing the heat-resistant resin is applied, and then a predetermined annealing heat treatment is carried out for exhibiting specific magnetic characteristics. The method for producing a magnetic core according to [1], in which the coating with the resin composition and the annealing heat treatment are performed in the same step.

[6] The method for producing a magnetic core according to [1], wherein the magnetic core after the annealing heat treatment is impregnated with the dispersion, and then the resin composition is applied to coat the magnetic core.

[7] A magnetic core manufactured by the method described in [1] to [6].

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A method of manufacturing a magnetic core according to the present invention comprises:
A method for producing a magnetic core composed of an amorphous alloy ribbon having an outer surface coated with a coating film, comprising: a dispersion in which particles having an average particle size of 500 nm or less are dispersed before coating the outer surface with the coating film. A method for producing a magnetic core is characterized in that the liquid is impregnated between the amorphous alloy ribbons of the magnetic core.

As the amorphous alloy ribbon according to the present invention, a soft magnetic material is targeted. For example, Fe-based or Co
Examples thereof include an amorphous metal material such as a Fe-based or Co-based nanocrystalline metallic material. Specifically, for example, F
As the e-based amorphous metal material, Fe-Si-B system, Fe
Fe-semi-metal type amorphous metal materials such as -B type and Fe-PC type, and Fe-transition metal type amorphous metal materials such as Fe-Zr type, Fe-Hf type and Fe-Ti type And the like. Examples of the Co-based amorphous metal material include Co-
Amorphous metal materials such as Si-B type and Co-B type can be mentioned. Further, in a nanocrystalline metal material obtained by crystallizing an amorphous metal material into a nanosize by heat treatment, Fe-Si-B-Cu-Nb system, Fe-B-Cu-
Nb type, Fe-Zr-B- (Cu) type, Fe-Zr-N
b-B- (Cu) system, Fe-Zr-P- (Cu) system, F
e-Zr-Nb-P- (Cu) system, Fe-Ta-C system,
Fe-Al-Si-Nb-B system, Fe-Al-Si-N
i-Nb-B system, Fe-Al-Nb-B system, Co-Ta
-C type etc. can be mentioned. These are all
In order to develop specific magnetic properties, an annealing heat treatment is performed under predetermined conditions before being normally used. The annealing heat treatment conditions vary depending on the type of material used and the magnetic characteristics to be exhibited, but the temperature range for amorphous metal materials is about 300.
~ 500 ° C, temperature range is about 4 for nanocrystalline metallic materials
Generally, the temperature is set to 00 to 700 ° C. The thickness of the amorphous alloy ribbon used in the magnetic core of the present invention is 1
It is preferably 0 to 100 microns, and 10 to 40
More preferably, it is micron.

The dispersion used in the present invention is a dispersion in which particles having an average particle diameter of 500 nm or less are dispersed. When the average particle diameter of the dispersed particles exceeds 500 nanometers, when the magnetic core is impregnated with the dispersion liquid, the particles are sufficiently inserted between the thin ribbons of the amorphous alloy thin ribbons forming the magnetic core. In addition, since the insulating property cannot be sufficiently achieved, the effect of the present invention may not be sufficiently obtained. The average particle diameter is more preferably 300 nanometers or less, further preferably 100 nanometers or less. The cohesiveness of the particles in the dispersion liquid is not particularly limited as long as the effect of the present invention is not impaired, but the cohesiveness is preferably low, and individual particles can be independently aggregated without aggregation. It is more preferable that they are dispersed. The average particle diameter in the present invention is a volume-based average particle diameter, and can be calculated by observing with a microscope such as SEM or TEM, or by measuring a particle diameter distribution using a laser diffraction / scattering method. Specific examples of the latter method include commonly used particle size measuring devices (Microtrac series manufactured by Nikkiso Co., Ltd., laser diffraction particle size distribution measurement device SALD series manufactured by Shimadzu Corp., etc.).

As the dispersion liquid used in the present invention, specifically, colloidal inorganic oxide dispersion liquid can be preferably used, and more specifically, colloidal silica dispersion liquid, colloidal titania dispersion liquid, colloidal zirconia dispersion liquid. It can be preferably used. As a dispersion medium of these dispersions, specifically, an organic solvent can be preferably used, and more specifically, methanol, ethanol, isopropyl alcohol, methyl ethyl ketone, acetone, ethylene glycol, dimethyl acetamide are preferably used. be able to. As specific examples of such a colloidal inorganic oxide dispersion, organosilica sol and Snowtex (registered trademark) manufactured by Nissan Chemical Industries, Ltd. can be preferably exemplified. As the dispersion liquid used in the present invention, specifically, an organic emulsion can be preferably used.

In the method for producing a magnetic core of the present invention, the operation of impregnating the dispersion liquid between the amorphous alloy ribbons of the magnetic core is performed before the operation of coating the outer surface of the magnetic core with the coating film. If the operation of impregnating the dispersion liquid between the amorphous alloy ribbons of the magnetic core is performed before the operation of coating the outer surface of the magnetic core with the coating film, for example, annealing heat treatment for expressing the magnetic characteristics, etc. The order of operations and the like is not particularly limited. For example, a method of performing annealing heat treatment in advance and then impregnating the dispersion liquid, and then coating the outer surface with a coating film, a method of impregnating the dispersion liquid, performing annealing heat treatment, and then coating the outer surface with a coating film. The order of other operations is not limited.

In the method for producing a magnetic core of the present invention, the kind and the coating method of the coating film for coating the outer surface of the magnetic core are not particularly limited as long as the effects of the present invention are not impaired. Any known technique can be adopted. For example, a method of coating the outer surface of the magnetic core with a thermosetting resin such as an epoxy resin using a method such as powder electrostatic coating can be specifically exemplified.

In the method for producing the magnetic core of the present invention, the method of impregnating the dispersion liquid between the amorphous alloy ribbons of the magnetic core is not particularly limited as long as the effects of the present invention can be obtained. For example, any known method such as a method of immersing the magnetic core in the dispersion or a method of immersing the magnetic core in the dispersion under reduced pressure can be used. The amount of the dispersion liquid to be impregnated is not particularly limited as long as the effect of the present invention can be obtained, but it is preferably 10% by volume or more of the voids between the amorphous alloy ribbons, and 30% by volume or more. Is more preferable.

In the method for producing the magnetic core of the present invention, the magnetic core before being subjected to the annealing heat treatment is impregnated with the dispersion liquid, then the resin composition containing the heat resistant resin is applied, and then the specific magnetic characteristics are expressed. A preferable example is a method of performing the predetermined annealing heat treatment performed in step 1, and performing the coating with the resin composition and the annealing heat treatment in the same step. The heat resistant resin is not particularly limited as long as it is a resin having sufficient heat resistance in annealing heat treatment, but a polyimide resin, a polyetherimide resin, a polyamideimide resin, a polyamide resin, a polysulfone resin. , And polyetherketone resins can be preferably used, and one kind or two or more kinds selected from these can be used in combination.

As a method for producing the magnetic core of the present invention, a method of suitably impregnating the magnetic core after the annealing heat treatment with the dispersion, and then applying the resin composition to coat the magnetic core can be suitably mentioned. The resin composition to be applied and the method of applying are not particularly limited, and examples thereof include powder electrostatic coating of epoxy resin.

[0025]

EXAMPLES The present invention will be described in detail below with reference to examples.

[0026]

Example 1 Atomic ratio of Fe: Si: B = 78: 9: 13
Amorphous alloy ribbon of composition (width 10 mm,
Thickness of 25 micron), thickness of 10 mm,
Inner diameter 15 mm, outer diameter 25 mm, weight 1
A magnetic core of 9.5 g was prepared. This magnetic core was completely immersed in Nissan Chemical Organosilica sol MA-ST-M and left under reduced pressure of about 10 kPa for 10 minutes to impregnate the organosilica sol between the amorphous alloy ribbons of the magnetic core. . In addition, when TEM observation of Nissan Chemical Co., Ltd. organo silica sol MA-ST-M,
The average particle diameter was 26 nanometers, which corresponded to the catalog value of 20-30 nanometers manufactured by Nissan Chemical Industries, Ltd. Next, Ube Industries, Ltd. polyimide powder UIP-
R was coated on the outer surface of a magnetic core impregnated with an organosilica sol by a usual powder electrostatic coating method, and then heated from 30 ° C. to 400 ° C. in a nitrogen atmosphere at a constant rate over 1 hour, After holding at 430 ° C. for 2 hours to perform annealing heat treatment, it was allowed to cool. The obtained magnetic core was in a state where the entire outer surface was covered with a uniform coating film. When the core loss was measured under the conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 tesla, it was 45 W / kg. The core loss of a blank magnetic core produced by heat-treating an equivalent magnetic core without being impregnated with an organosilica sol and without being covered with polyimide resin particles was 35 W / kg, which was obtained by the method of the present invention. The core loss of the magnetic core was 29% higher than that of the blank, and it was an excellent magnetic core in which the rate of increase compared to the blank remained at a low level.

[0027]

Example 2 Instead of polyimide powder as a resin used for coating, ALMATEX PD7 manufactured by Mitsui Chemicals, Inc.
After impregnating the organosilica sol in the same manner as in Example 1 except that the epoxy powder coating material in which 690 and dodecanedioic acid were mixed so that the equivalent ratio of glycidyl group / carboxylic acid group was 1/1, the epoxy resin A magnetic core was prepared by coating with a resin, and the core loss was measured. As a result 4
The magnetic core was as low as 8 W / kg and increased by 37% compared with the blank, which was an excellent magnetic core in which the rate of increase compared to the blank remained at a low level.

[0028]

Comparative Example 1 Admatex spherical silica fine particles Admafine SO-C3 were uniformly dispersed in pure water to a concentration of 10% by weight to obtain a dispersion liquid. Admafine S
When O-C3 was observed by SEM, the average particle diameter was 820 nanometers. A magnetic core was prepared by coating with a polyimide resin in the same manner as in Example 1 except that this dispersion was used, and the core loss was measured. As a result, it was as high as 98 W / kg, an increase of 180% compared to the blank,
The core loss was inferior.

[0029]

Comparative Example 2 A magnetic core was prepared by coating with a polyimide resin in the same manner as in Example 1 except that impregnation with the dispersion liquid was not performed, and the core loss was measured. As a result 105W
/ Kg, which was 200% higher than that of the blank, and the core loss was inferior.

[0030]

The method for producing a magnetic core of the present invention is a method of impregnating the amorphous alloy ribbon of the magnetic core with a specific dispersion liquid before coating the outer surface with a coating film, and the operation itself is very Moreover, it is not necessary to use a simple and expensive dispersion liquid itself. Further, it can be applied as it is to a core that has already been wound, and the space factor is not reduced. Therefore, it is an excellent method that can be applied without changing the existing process.

In the magnetic core manufactured by the manufacturing method of the present invention, the specific dispersion liquid is impregnated between the amorphous alloy ribbons of the magnetic core before coating the outer surface with the coating film. Compared with the magnetic core manufactured by the above method, the magnetic core has an excellent performance that the space loss is maintained and the reduction of the core loss characteristic is small. It is speculated that this is because the particles contained in the dispersion improve the insulation between the amorphous alloy ribbons of the magnetic core.

Claims (7)

[Claims] 1. A method for producing a magnetic core composed of an amorphous alloy ribbon, the outer surface of which is coated with a coating film, wherein the average particle size is 500 before the outer surface is coated with the coating film.
A method for producing a magnetic core, which comprises impregnating a dispersion liquid in which particles having a diameter of nanometer or less are dispersed between the amorphous alloy ribbons of the magnetic core. 2. The method for producing a magnetic core according to claim 1, wherein the dispersion is a colloidal inorganic oxide dispersion. 3. The colloidal inorganic oxide dispersion according to claim 2, wherein the dispersion medium is an organic solvent. 4. The method for producing a magnetic core according to claim 1, wherein the dispersion is an organic emulsion. 5. A magnetic core before being subjected to annealing heat treatment is impregnated with the dispersion liquid, then a resin composition containing a heat-resistant resin is applied, and then a predetermined annealing heat treatment is carried out for exhibiting specific magnetic characteristics. The method of manufacturing a magnetic core according to claim 1, wherein the coating with the resin composition and the annealing heat treatment are performed in the same step. 6. The method for producing a magnetic core according to claim 1, wherein the magnetic core after the annealing heat treatment is impregnated with the dispersion liquid, and then the resin composition is applied to coat the magnetic core. 7. A magnetic core manufactured by the method according to claim 1.