JPS59210626A - High-frequency core - Google Patents

Abstract

PURPOSE:To remove the layer short of a cut surface, and to reduce the high-frequency iron loss of a high-frequency core by a method wherein the laminated core formed by laminating a magnetic thin belt having high specific permeability and by impregnating with resin between the layers is cut, and the cut surfaces of the core body are finished to the surfaces removed with flashes generated at cutting time. CONSTITUTION:An amorphous magnetic thin belt is wound round elliptically to form a laminated core, and the laminated core is heat-treated. Then to fix the respective layers of the laminated amorphous magnetic thin belt with resin 6, the neighborhood of the central part of the long side of the laminated core is heated to be percolated with microcrystalline wax extending over about 20mm.. Then the laminated core impregnated with the resin 6 is cut by a GC microcutter to obtain a core body 1 of cut core. Then the shaded parts shown in the figure of the cut surfaces 2 are abraded by a proper abrasive plate up to obtain electric resistance of 0.3OMEGA/mm., and flashes 5 are removed. The fellow cut surfaces 2 are joined using two pieces of the core bodies 1 consisting of the U-type cut cores obtained in such a way to obtain the desired high-frequency core. Accordingly, the layer short of the cut surfaces to be generated according to the flashes 5 can be removed, and the high-frequency core reduced especially with high-frequency iron loss can be produced.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a high frequency core consisting of a cut core formed using an amorphous magnetic ribbon. [Background Art] Generally, the electrical resistance of an amorphous alloy is Rate is 50-350μ at room temperature
In Ω・m, the electrical resistivity is 10 to 10 compared to that of crystalline alloys.
0 times is huge. In particular, iron-based amorphous alloys suitable for transformer cores often have a resistance of 129 to 140 μΩ.

By the way, the eddy current loss among the components of iron loss is expressed by the following formula: α (m): Ribbon: Thickness of 71 sheets Bm (T): Maximum magnetic flux density ρ (Ω・m): Electricity Resistivity f (KHz): The same wave number iron loss is that work corresponding to the area surrounded by the magnetization ratio curve that makes the steresis curve become heat is lost in the ferromagnetic body, and the steresis loss Eddy current loss is divided into Joule heat eddy current loss and abnormal eddy current loss, which are determined by the percentage of eddy current generated in the magnetic core where alternating magnetic flux is generated. Particularly in the case of a high-frequency core, the latter is the main factor because the eddy current loss is proportional to the steresis loss, which is proportional to fl, while the steresis loss is proportional to fl.

Figure 1 shows a so-called force core obtained by winding and laminating amorphous magnetic ribbons and then cutting them. When an alternating magnetic field is applied to another core body, at least a part of the cut surface (part of the z-7 plane in Figure 1) becomes
If the layer is dimensionally short-circuited, an extremely large eddy current will occur on that surface, leading to an increase in eddy current loss and, therefore, an increase in core iron loss.

Currently, Metglas 2605 manufactured by Allied Chemical Co.
5-3 (trade name), an iron-based amorphous magnetic ribbon is wound, heat treated, cut, and butted together to form a U-shaped core body (1) <magnetic path length 110cm, cross-sectional area s o mrrz>. When excited with an alternating magnetic field of 20 KHz and 3 K Gauss, the iron loss We was 900 mw/cc (measured using a J-function meter), which was several times that of the ferrite core. ) was examined under a microscope and found to be approximately 80
% of the area was in a state of layer short circuit. The iron loss value before cutting was 300 mw/cc. By the way, as shown in Fig. 2, the amorphous magnetic ribbon used for the core body i11 has a thickness α generally of about 20 to 50 μm, and when it is made with a single wire, there are ridges (3) of several μm on the free surface. The roll surface has holes (4) of several to tens of micrometers in size, and the surface is rough, and the core is wound up with holes (3) on the free surface. Adjacent D-rule surfaces are laminated with point contact. When this is heat-treated, the surface of the magnetic ribbon of each layer of the laminated core body +11 is lightly oxidized or nitrided, or if impregnated with resin afterwards, it is slightly insulated. When the electrical resistance of the core body (1) was measured in the x-z plane by applying a low voltage, it was 0.1 to 1 Ω/m 2 . One side cut surface (2)
The layer shorted portion was 0.001Ω/m or less. The electrical resistance of the core material is mostly due to cutting (
6), and the electrical resistance of the cut surface (2) becomes 1/100 F or more between the layers (in the case of heat-treated amorphous metal), which causes an increase in eddy current loss.

[Purpose of the invention]

This invention has been made in view of the drawbacks mentioned above, and its purpose is to eliminate rare shorts on the cut surface, reduce iron loss,
In particular, the purpose is to provide a high frequency core with reduced high frequency core loss.

[Disclosure of the invention]

(Example 1) First, as an amorphous magnetic ribbon, the resistivity was 125μΩ・cy
++ (7) 'P 5 Metgla manufactured by Idoke Sanrikiru Co., Ltd.
s 26058-3 (product name) 35 μm (thickness), 1
The magnetic ribbon was wound in an oval shape, with a magnetic path length of 120 cm and a cross-sectional area of 50 mrr. A laminated core is formed, and a laminated core heat treatment is performed at 450° C. for 50 minutes in the atmosphere of a tooth scum. Next, in order to fix each layer of the laminated amorphous magnetic thin strips with resin (6), the vicinity of the center of the long side of the laminated core is heated and infiltrated with microblisterlin wax for about 20 degrees. In this case, resin impregnation allows the resin to penetrate deep into the interlayers, but in the case of iron-based amorphous materials, the effects of stress during curing and shrinkage are large, resulting in deterioration of properties, so only the outer mold of the laminated core is used. It's okay.

The laminated core impregnated with resin is cut with a GC micro cutter to obtain a core body +41, which is a so-called cut core, as shown in Fig. 1. In this case, the GC micro cutter is rotated at high speed. When the laminated core is cut a, a bulge (5) is generated on the cut surface (2) along the rotational direction of the GC microcutter due to suppressing friction, as shown in Fig. 3.
As shown in the enlarged cross-sectional view of Figure 2, there are magnetic ribbons (5
) is pressed against the cut surface of the lower layer magnetic ribbon, generating the above-mentioned layer short portion of electrical resistance. Therefore,
Use a suitable ordinary abrasive plate to polish the cut surface (2) in two axial directions (third
The burr (5) was removed by polishing the area (shaded area in the figure) until the electrical resistance became 0.3Ω/-.

Thus, the desired high-frequency core was obtained by using two core bodies fil made of the U-shaped cut [a] formed as described above and joining the cut surfaces (2) to each other. The specific high frequency core obtained in this way has an extremely low iron loss We at 20 KHz compared to the conventional example in which the core is not removed.

(Example 2) Next, as a magnetic ribbon, the composition was Fe C072B16.
Using a Si9 magnetic ribbon of 30 μm (thickness) and 10 strips (width), the magnetic ribbon was wound in a circle to create a magnetic path length of 100 m.
A laminated core with a cross section and area of 4 (jm-) is formed.The formed laminated core is heat treated in a vacuum at 350°C for 20 minutes. and hardener HY2967 at a ratio of 100:35) was impregnated between the layers of the laminated core under reduced pressure, and then the impregnated resin (6) was cured at 100° C. for 3 hours.

Next, the resin-impregnated and hardened laminated core is cut into, for example, a C-shape by rotating a GC blade to obtain a core body +1+. The cut surface (2) of this core body il+ has a beam (
6), therefore, in this embodiment, electrolytic polishing is performed to remove the burrs (5). In this case, it is necessary to impregnate the core body il+ with resin at least at a depth in the X-axis direction from the cut surface (2) to prevent the conductive liquid used for electrolytic polishing from penetrating deep into the interlayers due to capillary action. be. In other words, if the conductive liquid penetrates deep into the interlayers, the electrical resistance between the layers may decrease, leading to an increase in eddy current loss. Further, if the electrolytic conditions become excessive, the magnetic ribbon of the core body (1) becomes even thinner, and the expiration magnetic flux density increases in that part, and the iron loss We increases according to the above equation, so care must be taken.

In this example, however, the burr (5) was removed by performing electric polishing until the electrical resistance of the cut surface (2) in the Z-axis direction became 0.5 Ω/k. Using two core bodies fil, which are the cut cores obtained in this way, the cut surfaces (2) are joined together, an alternating magnetic field of 2 K Gaus6 at 50 KHz is applied, and the iron loss We'fr is measured using a U function meter.
It was a small value of 4 gQmw/cc. In addition, in the non-polished state, the value of iron loss We was a large value of B 00 mw/cc.

In addition to the magnetic ribbons used in Example 1, there are, for example, amorphous magnetic ribbons having compositions as shown in the following table.

There are, of course, countless examples of ferromagnetic formulations other than the above table, and the present invention is not limited to the table and examples.

Furthermore, the temperature at which the amorphous magnetic ribbon is heat-treated varies depending on the purpose of use, and examples thereof are shown in the following table.

Further, as the impregnating resin (6), polyester resin, silicone resin, etc. may be used in addition to the above-mentioned embodiments. In particular, in the case of an iron-based amorphous magnetic plate, the magnetostriction is large, so it is necessary to select a resin with a small coefficient of linear expansion.

In addition, the impregnated resin (6) serves as a means of fixing during polishing and etching when removing the burrs (6) after cutting, and fixing during electrolytic polishing, and can be melted and removed as necessary after removing the burrs. Good too.

〔Effect of the invention〕

The present invention is a face cutter in which burrs generated during cutting are removed from the cut surface of a core body formed by cutting a laminated core in which magnetic ribbons having high relative magnetic permeability are laminated and resin is impregnated between the layers. Therefore, it is necessary to eliminate the layer short in the laminated magnetic thin strips due to the bending. The eddy current caused by layer short when I is excited by high frequency,
It is possible to prevent iron loss from increasing or increasing, and as a result, it is possible to reduce iron loss, and it is also possible to use it with high efficiency in transformers and chokes such as transistor inverters that use high frequencies. In addition, as mentioned above, the impregnated resin can provide insulation between layers, and also serves as a means for fixing the layers during polishing and cutting, making cutting and polishing operations easier.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a core body as a cut core, FIG. 2 is an explanatory diagram of the main parts of a conventional example, FIG. 3 is an explanatory diagram of the main parts of an embodiment of the present invention, and 11) is a diagram of the core body. , 12) is the cut plane, (5
1 is the burr, and (6) is the impregnated resin. Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] +11 The core body is formed by cutting a laminated core in which magnetic ribbons having a high relative magnetic permeability are laminated and resin is impregnated between the layers, and the cut surface is a surface from which burrs generated during cutting are removed. high-volume core 0