JPH0661070A - Core for transformer - Google Patents

Abstract

PURPOSE:To improve the permeability of a core for a transformer wherein the industrial mass production of transformers can be realized, by bonding a plurality of core segments to the part between fitting surfaces which face each other, via layers composed of ferromagnetic metal. CONSTITUTION:Core segments 10 and 20 are manufactured by using pre-baking powder whose main component is Fe2O3, MnO and ZnO to which SiO2 and CaO are added. Fitting surfaces 11, 12, 13 and 21 of both core segments are ground and flattened by using a grindstone. Each of the ground surfaces 11, 12, 13 and 21 is coated with coating material composed of iron carbonyl. Polyester-covered wire is wound around the central magnetic leg. The core segment 10 is brought into close contact with the core segment 20 via the fitting surfaces, and the core segment is fixed to the core segment 20 with pressure by using a jig spring. After the core in this state is heat-treated in an H2 atmosphere, it is cooled as far as a room temperature and taken out. Thereby the industrial mass production of transformers is realized, the leakage of magnetic flux can be prevented, and high permeability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core used in electronic equipment such as a transformer, and more particularly to a core for a transformer formed by combining a plurality of core pieces.

[0002]

2. Description of the Related Art Generally, for the purpose of industrial mass production of a transformer, a core for a transformer is formed by, for example, inserting a bobbin having a wound coil into a core piece into which a core is divided into two, and then combining the two core pieces. Manufactured. For this reason, the core for transformer is formed with a grinding surface. Usually, this ground surface is subjected to polishing.

Normally, the smoothness and parallelism of this divided surface are adjusted so that they can be ground by polishing. However, since the polishing process cannot be precisely performed due to the cost limitation, the polishing process is performed once with several hundreds of grindstones. Therefore, the processed surface has a roughness of several tens of μm.
In order to bring together cores having surface coarse soil of this degree, it is inevitable that a gap will be partially formed at the joining portion. This is the same as the air gap.

[0004]

However, in terms of productivity and manufacturing cost, the grinding of the mating surface is not performed precisely, and it is only carried out once with a grindstone of several hundreds of abrasive grains. . Therefore, the processed surface has a roughness of several tens of μm. Since the core pieces having such a surface roughness are rubbed together, a gap is formed between the lapped surfaces. This gap is a so-called air gap. If there is an air gap in a part of the core, leakage of magnetic flux occurs, magnetic permeability decreases, and iron loss increases. In other words, industrially mass-produced transformer cores have a problem that they are used in a state in which they are deteriorated from the original material characteristics.

Such a problem does not exist in a core made as an integrated body that does not combine a plurality of magnetic cores like an annular magnetic core, but on the contrary, there is a problem that the transformer manufacturing cannot be completely automated. There are advantages and disadvantages.

An object of the present invention is to improve the magnetic permeability of a transformer core which can realize industrial mass production of transformers.

[0007]

According to the present invention, there is provided a plurality of core pieces having a mating surface, the plurality of core pieces comprising:
In the transformer core to be combined by facing each of the mating surfaces, the plurality of core pieces are joined to each other between the mating surfaces facing each other through a layer made of a ferromagnetic metal. A transformer core to be obtained is obtained.

According to the present invention, further, there is provided a plurality of core pieces having a mating surface, and the plurality of core pieces are the cores for transformers to be assembled by facing each other of the mating surfaces. Of the core piece of Fe (CO) ₅ , Fe ₂ (CO) ₄ Co between the facing surfaces facing each other.
Heat treatment in an inert atmosphere or a reducing atmosphere after applying a coating material comprising at least one selected from ₂ (CO) ₈ , Mn ₂ (CO) ₁₀ and Ni (CO) _4. By doing so, a transformer core characterized in that they are joined via a layer made of a metallized ferromagnetic metal is obtained.

That is, according to the present invention, like the E-type core, the EI-type core, and the pot core which are mass-produced,
In a transformer core formed by combining core pieces of one kind or two or more shapes, when a wound coil is inserted and core parts are closely adhered at several rubbed portions to form a transformer, Fe (CO) ₅ , Fe ₂ (CO) ₄ , Co ₂ (C
_{O) 8, Mn 2 (CO} ) 10, Ni (CO) is _{to 4} is applied to one or sliding fit section two or more single or a mixture selected from then heat-treated in a reducing atmosphere Ri mating portion By forming a layer of metallic iron, metallic Mn, metallic cobalt, or an alloy thereof on the above, the ground portion is adhered to these layers, and the polishing groove is filled with metal, so that the ground portion is substantially magnetic. It will have a structure filled with the body. Therefore, the high-performance magnetic core can be manufactured at a relatively low cost, because the deterioration of the core characteristics due to the material characteristics of the ferrite material is made smaller than that of the core without the coating member.

[0010]

In the coating material of the present invention, for example, iron carbonyl can be reduced to obtain metallic iron. The magnetic permeability of metallic iron is from several thousand to about 200,000,
It is considered that since a magnetic material having a magnetic permeability higher than that in air fills the gap of the lapped portion, the magnetic resistance is reduced, the leakage magnetic flux can be reduced, and the inductance is improved. Similarly for other materials, it is considered that the inductance can be improved by filling the gap of the bonded portion with powder having a magnetic permeability relatively higher than that of air.

The carbonyl reduction treatment conditions must be selected so that the characteristics of the ferrite sintered body are not deteriorated by reducing the ferrite sintered body and the wound coil cannot be covered. Therefore, the reduction treatment temperature is preferably 800 ° C. or lower. Also, considering the heat resistant temperature of the insulator of the wound coil, 5
It is preferably 00 ° C or lower.

[0012]

Embodiments of the transformer core according to the present invention will be described below.

First Embodiment FIG. 1 is an exploded perspective view of a transformer core according to a first embodiment. In FIG. 1, this core is an E-shaped core piece 1
It has 0 and the core piece 20 which exhibits I type. Core piece 10
Has rubbing surfaces 11, 12 and 13 on the tip end surface of each magnetic leg. The core piece 20 has a rubbing surface 21 on one side surface thereof.

Next, the core according to the first embodiment will be described in more detail with reference to its manufacturing process.

Fe ₂ O ₅ (52 mol%), MnO
(38 mol%) and ZnO (10 mol%) as main components, and SiO ₂ and CaO are added to the pre-calcined powder to manufacture core pieces 10 and 20 shown in FIG. 1.

The mating surfaces 11, 12, 1 of both core pieces
Polish 3 and 21 with a whetstone ( ^# 320) to smooth.

On the other hand, a coating agent containing iron carbonyl
It is applied to each of the ground mating surfaces 11, 12, 13 and 21, and a polyester coated wire (diameter 0.3 mm) is wound around the central magnetic leg of the core piece 10 (not shown) to form the core piece 10 and the core. The piece 20 and the piece 20 are brought into close contact with each other on the mating surface, and fixed by weight using a jig spring (not shown).

The core in this state is placed in an H ₂ atmosphere for 300 times.
After holding at ℃ for 2 hours, it is cooled to room temperature and taken out.

As described above, the transformer core according to Example 1 could be manufactured.

The effective magnetic permeability of the obtained core was 3080. As a comparative example, the effective permeability of a core not coated with iron carbonyl was measured and found to be 210
It was 0, and it was confirmed that the magnetic permeability was improved about 1.5 times.
The core has an effective area of 1.18 cm ² and an effective magnetic path length of 6.70 cm.

Example 2 In Example 2, the coating agent applied to each of the mating surfaces was
Iron carbonyl and manganese carbonyl in a weight ratio of 6
A mixture of 6.8: 33.2 was used. A core was produced in the same manner as in Example 1 except for this coating agent.
The effective magnetic permeability of the obtained core was 2950. Therefore, it can be seen that also in Example 2, the magnetic permeability was improved to about 1.5 times that of the core according to the comparative example.

Example 3 In Example 3, the coating agent applied to each of the mating surfaces was
Iron carbonyl Fe (CO) ₅ and nickel carbonyl N
A mixture of i (CO) ₄ in a weight ratio of 2: 8 was used. A core was produced in the same manner as in Example 1 except for this coating agent. The effective magnetic permeability of the obtained core was 3350. Therefore, it can be seen that also in Example 3, the magnetic permeability is improved to about 1.5 times that of the core according to the comparative example.

Example 4 In Example 4, the coating agent applied to each of the mating surfaces was
Iron carbonyl Fe (CO) ₅ and cobalt carbonyl C
A mixture of o ₂ (CO) ₈ and O ₂ (CO) ₈ in a weight ratio of 2: 1 was used. A core was produced in the same manner as in Example 1 except for this coating agent. The effective magnetic permeability of the obtained core is 3510.
Met. Therefore, it can be seen that also in Example 4, the magnetic permeability was improved to about 1.7 times that of the core according to the above-described comparative example.

[0024]

According to the present invention, since a plurality of core pieces are bonded to each other between the facing mating surfaces through a layer made of a ferromagnetic metal, it is possible to realize industrial mass production of the transformer and, No leakage occurs and high magnetic permeability is obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating a transformer core according to an embodiment of the present invention.

[Explanation of symbols]

 10, 20 Core pieces 11-13, 21 Lapping surface

Claims (2)

[Claims] 1. A transformer core, comprising: a plurality of core pieces each having a mating surface, wherein the plurality of core pieces are combined with each other so that the mating surfaces face each other. A core for a transformer, characterized in that it is bonded between the facing mating surfaces with a layer made of a ferromagnetic metal interposed therebetween. 2. A transformer core, comprising: a plurality of core pieces each having a mating surface, wherein the plurality of core pieces face each other with the mating surfaces facing each other; Between the facing surfaces facing each other, Fe
(CO) ₅ , Fe ₂ (CO) ₄ Co ₂ (CO) ₈ , Mn
A strong metallized material obtained by heat-treating a coated material composed of at least one selected from ₂ (CO) ₁₀ and Ni (CO) ₄ in either an inert atmosphere or a reducing atmosphere after coating. A transformer core, which is joined through a layer made of magnetic metal.