JPH07326533A - Production of magnetic core - Google Patents

Abstract

PURPOSE:To reduce the iron loss and improve the drop in production yield due to iron core disintegration by laminating or winding up a metallic magnetic thin band at a specified space factor, and then resin-immersing/curing it and cutting off a part of the core. CONSTITUTION:A thin film is laminated or wound up to form a core in a manner that the space factor of thin band made of amorphous magnetic alloy with excellent soft magnetic property 80% or higher. In the case where the space factor is 80% or higher the deterioration of magnetic property of the obtained magnetic core is suppressed significantly since an amount of immersed resin decreases. Next, the obtained core is immersed in a specific resin liquid such as an epoxy. Then, after applying resin-immersing/curing treatment, a part of the core is cut off for used in choke coil, etc. Thus, the iron loss can be reduced and the drop in production yield due to iron core disintegration can be suppressed at the same time.

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,
More specifically, the present invention relates to a method of manufacturing a magnetic core having small iron loss and stable magnetic characteristics.

[0002]

2. Description of the Related Art Recently, a thin ribbon of an amorphous magnetic alloy is being used as a magnetic core material for laminated magnetic cores and wound magnetic cores provided in various inductors such as transformers. This ribbon is made of metal (eg Fe, Co) and semi-metal (eg B, P, Si).
It is manufactured by cooling a melt of a magnetic alloy containing and in a predetermined ratio by a conventional ultraquenching method. The obtained ribbon is amorphous and has excellent soft magnetic properties.

When manufacturing a magnetic core from this ribbon, first, the ribbon is laminated or wound to produce a molded core, and at that time, for example, a resin liquid is impregnated in the whole and the resin liquid is cured. is there. This is to prevent the magnetic core from disassembling at the time of cutting a part of the magnetic core in the application field such as choke coil and transformer core.

In this resin impregnation treatment, the above molding core is immersed in a resin liquid to allow the resin liquid to penetrate into the fine voids between the respective ribbons, and then the resin is cured to mutually bond the ribbons. It is what makes them stick. Thus, when the magnetic core is cut and its cross-section is observed, it has a structure in which a plurality of thin ribbon layers and a plurality of resin layers cured in the spaces between the thin ribbons are alternately laminated. Become.

Here, the area ratio occupied by the entire thin ribbon layer in the cross section is referred to as a normal space factor and is expressed as a percentage (%).

[0006] In such a magnetic core, an epoxy-based resin has been widely used as a resin to be impregnated in the related art, because it shrinks greatly during curing and can firmly bond the ribbons.

However, when such a resin having a large shrinkage hardening is used, the ribbon fixing ability is certainly improved, but on the other hand, the ribbon receives a shrinking force of the resin and has a large positive magnetostriction. A phenomenon occurs in which magnetic anisotropy occurs and the magnetic characteristics of the magnetic core after resin curing deteriorates from the values originally planned. That is, when the resin is cured, the contraction force causes strain on the ribbon, which causes a phenomenon such as an increase in iron loss of the obtained magnetic core. This tendency is remarkable when the magnetostriction is large, that is, in the case of the iron-based amorphous magnetic alloy ribbon.

[0008]

As described above, in the case of the laminated magnetic core or the wound magnetic core fixed by the resin, especially when the iron-based amorphous magnetic alloy is used as the ribbon, the magnetic characteristics vary. There has been a problem that the magnetic properties of the magnetic core cannot be expected.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a method of manufacturing a magnetic core which does not change magnetic characteristics due to shrinkage hardening of a resin and which has a particularly small iron loss.

[0010]

Means and Actions for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object. As a result, after laminating or winding metallic magnetic ribbons at a space factor within a predetermined range, resin When impregnation / curing treatment was performed and then a part of the core was cut, the fact that the deterioration of the magnetic properties of the obtained magnetic core was extremely small was found, and the method for producing the magnetic core of the present invention was developed. .

That is, in the method of manufacturing a magnetic core of the present invention, after laminating or winding a metal magnetic ribbon at a space factor of 80% or more, resin impregnation / curing treatment is performed, and then a part of the core is cut. Is characterized by.

First, the metallic magnetic ribbon used for the magnetic core of the present invention may be any ribbon as long as it is a material applicable to the so-called magnetic core, but is a ribbon of an amorphous magnetic alloy which is particularly excellent in soft magnetic characteristics. Is preferred. This amorphous magnetic alloy ribbon having excellent soft magnetic characteristics is a conventional ultra-quenched melt of a magnetic alloy containing a metal (for example, Fe, Co) and a semimetal (for example, B, P, Si) in a predetermined ratio. It is manufactured by cooling by the method.

Specifically, for example, the formula: Fe _a M _b Y _c (where M is Ti, V, Cr, M
n, Co, Ni, Zr, Nb, Mo, Hf, Ta, W,
Re, Ga, Ru, Rh, Pd, Os, Ir, Pt, and at least one element selected from the group of rare earths;
Y represents at least one element selected from the group consisting of Si, B, P and C; a, b and c are each 65 ≦ a ≦ 8.
5,0 ≦ b ≦ 15,5 ≦ c represents a number satisfying the relation of ≦ 35) amorphous magnetic alloy of iron-based represented by or _{wherein,: Co d Fe e M'f} Y'g M' is Ti, V, Cr, Mn, Co, Ni, Zr, N
b, Mo, Hf, Ta, W, Re, Ga, Ru, Rh,
Pd, Os, Ir, Pt, and at least one element selected from the group of rare earths; Y'is Si, B, P, C
Represents at least one element selected from the group: d,
e, f, and g are 60 ≦ d ≦ 80 and 1 ≦ e ≦ 1, respectively.
Cobalt-based amorphous magnetic alloys represented by 0, 0 ≤ f ≤ 10, 15 ≤ g ≤ 30 (atomic%) are preferable.

In particular, an amorphous magnetic alloy ribbon having a positive magnetostriction has a large effect and is useful.

The ribbon can be easily manufactured by the ultraquenching method.

In the method of manufacturing a magnetic core of the present invention, first, the above-mentioned thin strips are laminated or wound to form a core.
At this time, it is formed so that the space factor of the ribbon is 80% or more. When the space factor is 80% or more, the amount of resin impregnated becomes small, so that the magnetic properties of the obtained magnetic core are deteriorated, for example, iron loss is significantly reduced. A space factor of more than 95% is practically difficult due to the surface condition of the ribbon and the thickness of the ribbon. A preferred space factor is 85% to 9
5%.

For such a space factor, for example, in the case of a wound magnetic core, the ribbon is wound while applying a predetermined tensile force, or the ribbon manufacturing conditions are selected or the ribbon surface is polished. It can be arbitrarily determined by a method such as smoothing the surface of the surface.

Next, the obtained molding core is immersed in a predetermined resin liquid. The resin used may be the one described above.

Further, after the resin impregnation curing treatment, a part of the core is cut for use as a choke coil, a transformer core and the like.

[0020]

【Example】

(Example 1) The composition is (Fe _0.97 Nb _0.03 ) ₈₂ Si ₆ B ₁₂
Then, a ribbon of an amorphous magnetic alloy having a width of 10 mm and a thickness of 25 μm was manufactured by the single roll method.

Next, the thin strip was wound to form wound magnetic cores (outer diameter 18 mm, inner diameter 12 mm, thickness 10 mm) having different space factors. After heat-treating these magnetic cores at about 460 ° C. for 1 hour, the magnetic cores were immersed in an epoxy resin solution and heat-cured at about 120 ° C. for 1 hour, and then the magnetic cores were partially cut.

The iron loss of each of the obtained magnetic cores at room temperature was measured under the conditions of a frequency of 50 kHz and an operating magnetic flux density of 3 kG.

The results are shown in FIG. As is clear from FIG. 1, the magnetic core obtained by the manufacturing method of the present invention, in which the magnetic ribbon is wound, resin-impregnated and cured, and then a part of the core is cut, has a space factor of 80% or more. It can be seen that the effect of reducing the iron loss can be remarkably obtained by winding. The iron loss of these magnetic cores before resin impregnation was 430 to 460 mW / cc. (Example 2) The composition is Co ₆₉ Fe ₄ Cr ₂ Si ₁₃ B ₁₂ , and
A ribbon of amorphous magnetic alloy having a width of 10 mm and a thickness of 20 μm was manufactured by a single roll method.

Then, the thin strip was wound to form wound magnetic cores (outer diameter 18 mm, inner diameter 12 mm, height 10 mm) having different space factors. After heat-treating these magnetic cores at 440 ° C. for 1 hour, the magnetic cores were immersed in an epoxy resin solution and heat-cured at about 120 ° C. for 1 hour, and then the magnetic cores were partially cut.

The iron loss of each obtained magnetic core at room temperature was measured under the conditions of a frequency of 50 kHz and an operating magnetic flux density of 3 kG.

The results are shown in FIG. As is clear from FIG. 2, the magnetic core obtained by the manufacturing method of the present invention in which the magnetic ribbon is wound, resin impregnated and cured, and then a part of the core is cut, has a space factor of 80% or more. It can be seen that the effect of reducing the iron loss can be remarkably obtained by winding. The iron loss of these magnetic cores before impregnating with resin was 340 mW / cc.

According to the method of manufacturing a magnetic core of the present invention, 8
Since a part of the magnetic core is cut after being wound at a high space factor of 0% or more and further subjected to resin impregnation curing treatment, decomposition of the magnetic core at the time of cutting can also be suppressed.

[0028]

As is clear from the above description, according to the method for manufacturing a magnetic core of the present invention, the magnetic core is wound at a space factor of 80% or more,
Further, since a part of the magnetic core is cut after the resin impregnation curing treatment is performed, it is possible to reduce the iron loss and at the same time, reduce the manufacturing yield due to the decomposition of the magnetic core. Therefore, it is extremely useful as a method for manufacturing a magnetic core for choke coils and transformer coils.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a space factor and a core loss of a magnetic core manufactured in Example 1.

FIG. 2 is a diagram showing a relationship between a space factor and a core loss of a magnetic core manufactured in Example 2.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01F 27/24 (72) Inventor Yoshiyuki Yamauchi 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Corporation Inside Yokohama Metal Factory

Claims (3)

[Claims] 1. A method for producing a magnetic core, comprising laminating or winding metal magnetic ribbons at a space factor of 80% or more, impregnating with a resin and curing the resin, and subsequently cutting a part of the core. 2. The method of manufacturing a magnetic core according to claim 1, wherein the metallic magnetic ribbon is a ribbon of an amorphous magnetic alloy. 3. The method for producing a magnetic core according to claim 2, wherein the amorphous magnetic alloy has a positive magnetostriction.