JP3183857B2 - Low frequency transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-frequency transformer suitable as an inverter transformer used in a low-frequency region or a power distribution transformer used in a commercial frequency.

[0002]

2. Description of the Related Art Conventionally, silicon transformers having a high saturation magnetic flux density and a relatively low iron loss are mainly used in inverter transformers used in a low frequency range and power distribution transformers used in a commercial frequency. . Japanese Patent Publication No. 62-37688 and Japanese Patent Publication No.
As disclosed in Japanese Patent No. 45285, improvement in magnetic flux density and reduction in iron loss are achieved by techniques such as recrystallization by rolling and annealing.

In recent years, with the progress of the ultra-quenching method, high-silicon Si foil strips and iron-based amorphous alloy thin strips with low iron loss have been produced, and are attracting attention as low-frequency transformer materials. Among these, iron-based amorphous alloys have attracted attention as energy-saving materials because of their iron loss at commercial frequency, which is a fraction of that of silicon steel plates, and some of them have been put to practical use.

[0004]

However, since the silicon steel sheet does not have a sufficiently low iron loss, it is not sufficiently satisfactory in terms of energy saving, heat generation of a transformer, and the like. Further, the conventional silicon steel sheet has a problem that the saturation magnetic flux density is lower than that of the iron-based amorphous alloy.

[0005] On the other hand, iron-based amorphous alloys have a small iron loss, but have a remarkably large magnetostriction and are sensitive to stress. is there.

Based on such a background, the present inventors have previously proposed an Fe-based soft magnetic alloy having a high saturation magnetic flux density in Japanese Patent Application No. Hei.
No. 08308, filed on April 24, 1990.

Another one of the alloys according to this patent application is a high saturation magnetic flux density alloy having a composition represented by the following formula. (Fe1-aCoa) bBxTyT'z

Where T is Ti, Zr, Hf, V, Nb, Ta, M
o, one or more elements selected from the group consisting of W, and contains one or both of Zr and Hf, and T ′ is from Cu, Ag, Au, Ni, Pd, and Pt. One or more elements selected from the group consisting of: a ≦ 0.0
5, b ≦ 92 at%, x = 0.5 to 16 at%, y = 4 to 1
0 atomic% and z = 0.2 to 4.5 atomic%.

Another one of the alloys according to the patent application is a high saturation magnetic flux density alloy having a composition represented by the following formula. Feb BxTyT'z

Where T is Ti, Zr, Hf, V, Nb, Ta, M
o, one or more elements selected from the group consisting of W, and contains one or both of Zr and Hf, and T ′ is from Cu, Ag, Au, Ni, Pd, and Pt. One or more elements selected from the group consisting of: b ≦ 92 at%, x = 0.5 to 16 at%, y = 4 to 10 at%, z =
0.2 to 4.5 atomic%.

Further, the present inventors have previously filed a patent application for an alloy having the following composition as an advanced alloy of the above alloy.

One of the alloys according to this patent application is a high saturation magnetic flux density alloy having a composition represented by the following formula. (Fe1-aQa) bBxTy

Where Q is either or both of Co and Ni, and T is Ti, Zr, Hf, V, Nb, Ta, Mo, W
One or two or more elements selected from the group consisting of: Zr, Hf, or both, and a ≦
0.05, b ≦ 93 at%, x = 0.5 to 8 at%, y = 4
９9 atomic%.

Another one of the alloys according to the patent application is a high saturation magnetic flux density alloy having a composition represented by the following formula. FebBxTy

Where T is Ti, Zr, Hf, V, Nb, Ta, M
one or two or more elements selected from the group consisting of o and W and containing either or both of Zr and Hf, b ≦ 93 at%, x = 0.5 to 8 at% , Y = 4 to 9 at%.

As described above, the present inventors have developed various Fe-based soft magnetic alloys having the above-mentioned compositions. As a result of repeated studies on the alloys having the above-mentioned compositions, they have been used for transformers. It was also found that good characteristics were obtained, and the present invention was reached.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a low-frequency transformer which exhibits high saturation magnetic flux density, has low iron loss in a low-frequency region, and has excellent heat resistance. I do.

[0018]

According to the first aspect of the present invention, there is provided a high-saturation magnetic flux having a composition represented by the following formula and having a saturation magnetic flux density of 14.6 kG or more . Ri Do from the alloy and the conductor, frequency 50Hz,
Iron loss at a magnetic flux density of 12 kG is 0.22 W / kg or less
This is a low-frequency transformer . (Fe1-aCoa) b BxTyT'z

Where T is Ti, Zr, Hf, V, Nb, Mo, W
One or two or more elements selected from the group consisting of: Zr, Hf, or both, and T ′
Is one or two elements selected from the group consisting of Cu and Au , and a ≦ 0.05, 84 at% ≦ b ≦ 92 at%, x
= 0.5 to 8 at %, y = 4 to 10 at%, and z = 4.5 at% or less.

According to a second aspect of the present invention, there is provided a magnetic head having a saturation magnetic flux density having a composition represented by the following formula:
Ri but Do and a more high saturation magnetic flux density Fe-based soft magnetic alloy and lead 14.6 kg, frequency 50 Hz, magnetic flux density 12kG
Frequency transformer with iron loss of 0.22 W / kg or less
Is Nsu. FebBxTyT'z

Where T is Ti, Zr, Hf, V, Nb, Mo, W
One or two or more elements selected from the group consisting of: Zr, Hf, or both, and T ′
Is one or two elements selected from the group consisting of Cu and Au , and 84 at% ≦ b ≦ 92 at%, x = 0.5 to 8
Atomic%, y = 4 to 10 atomic%, and z = 4.5 atomic% or less.

According to a third aspect of the present invention, in order to solve the above-mentioned problems, there is provided the above-mentioned group in which an insulating layer made of MgO is formed.
Of high saturation magnetic flux density Fe-based soft magnetic alloy
This is a low-frequency transformer with a magnetic core.

In the above invention, since the transformer is formed using a soft magnetic alloy having a specific composition, a low frequency transformer having both high saturation magnetic flux density and high magnetic permeability and having thermal stability can be obtained.

[0024]

Figure 1 DETAILED DESCRIPTION OF THE INVENTION show an embodiment of a transformer according to the present invention, the transformer T of this embodiment includes a pair of magnetic core 1, formed by wound magnetic core 1, 1 wound conductive wire 2 Is mainly composed. As shown in FIG. 2, the magnetic core 1 is formed by winding a thin ribbon. This ribbon is Fe ₉₀ Zr
_It comprises a soft magnetic alloy ribbon having a composition such as ₇ B ₂ Cu ₁ and an insulating layer such as MgO formed on one surface of the soft magnetic alloy ribbon.

It should be noted that one of the soft magnetic alloys constituting the ribbon is
First, a high saturation magnetic flux density Fe-based soft magnetic alloy having a composition represented by the following formula can be used. (Fe1-aCoa) bBxTyT'z

Where T is Ti, Zr, Hf, V, Nb, Mo, W
One or two or more elements selected from the group consisting of: Zr, Hf, or both, and T ′
Is one or two elements selected from the group consisting of Cu and Au , and a ≦ 0.05, 84 at% ≦ b ≦ 92 at%, x
= 0.5 to 8 at %, y = 4 to 10 at%, and z = 4.5 at% or less.

One of the soft magnetic alloys constituting the ribbon is a high saturation magnetic flux density Fe having a composition represented by the following formula.
Soft magnetic alloys can be used. FebBxTyT '
z

Where T is Ti, Zr, Hf, V, Nb, Mo, W
One or two or more elements selected from the group consisting of: Zr, Hf, or both, and T ′
Is one or two elements selected from the group consisting of Cu and Au , and 84 at% ≦ b ≦ 92 at%, x = 0.5 to 8
Atomic%, y = 4 to 10 atomic%, and z = 4.5 atomic% or less.

The soft magnetic alloy used in the present invention is obtained by quenching an amorphous alloy having the above composition or a crystalline alloy containing an amorphous phase from a molten metal, and heating this to form fine crystal grains. Can usually be obtained by a heat treatment step.

In the soft magnetic alloy used in the transformer of the present invention, in order to easily obtain an amorphous phase, it is necessary to include either Zr or Hf having a high amorphous forming ability. Also Z
r and Hf are partly represented by T among other 4A to 6A elements.
i, V, Nb, Mo, W can be substituted. Where C
The reason why r was not included is that Cr is inferior to other elements in amorphous forming ability. However, if an appropriate amount of Zr and Hf is added, Cr may be further added. It is.

It is considered that B has the effect of increasing the ability of the alloy used in the present invention to form an amorphous phase and the effect of suppressing the formation of a compound phase that adversely affects magnetic properties in the heat treatment step. Is required. Like B, Al, Si, C, P, etc. are generally used as amorphous forming elements, and the addition of these elements can be regarded as the same as in the present invention.

At least one element or two or more elements selected from Cu and its homologous elements as the T ′ component is not more than 4.5 atomic%, more preferably not more than 0.2 atomic%.
When 4.5 atomic% is blended, excellent soft magnetic properties can be obtained by the heat treatment step. Among these elements, Cu is particularly preferred.

When the amount z of the T 'component is less than 0.2 atomic%, it is desirable to increase the cooling rate after the heat treatment. FIG. 3 shows the result of measuring the magnetic permeability after heating a sample of a soft magnetic alloy having a composition of Fe ₈₈ Cu ₁ B ₃ Zr ₈ at 650 ° C. for 1 hour and then cooling at various cooling rates. 5 is a graph showing the relationship between the magnetic permeability and the magnetic permeability. This graph shows that increasing the cooling rate improves the magnetic permeability. When the T ′ component is less than 0.2 atomic%, the magnetic permeability tends to decrease, but by increasing the cooling rate as described above, the tendency of the magnetic permeability to decrease can be canceled.

[0034] a The T 'component, the addition of Cu or the like, is not clear about the mechanism of soft magnetic characteristics are significantly improved, the crystallization temperature was measured by differential thermal analysis, was added Cu, etc. The crystallization temperature of the alloy was found to be slightly lower than the alloy without addition.
This is because the addition of the element makes the amorphous phase non-uniform,
As a result, it is considered that the stability of the amorphous phase was reduced. Further, when a non-uniform amorphous phase is crystallized, a large number of regions are likely to be partially crystallized and non-uniform nuclei are generated, so that the obtained structure is considered to be a fine crystal grain structure.

In particular, in the case of Cu, which is an element having a very low solid solubility in Fe, phase separation tends to occur, so that micro-composition fluctuations occur due to heating and the amorphous phase becomes more non-uniform. This is considered to contribute to the refinement of the structure.

From the above viewpoints, other than Cu and its homologous elements
The same effect can be expected for the element which lowers the crystallization temperature. Similar effects can be expected for elements such as Cu which have a small solid solubility limit with respect to Fe.

The reasons for limiting the alloy elements contained in the high saturation magnetic flux density Fe-based soft magnetic alloy of the present invention have been described above. In order to improve corrosion resistance other than these elements, Cr, R
u It is also possible to add other platinum group elements,
If necessary, Y, rare earth elements, Zn, Cd, Ga,
In, Ge, Sn, Pb, As, Sb, Bi, Se, Te, Li,
Magnetostriction can also be adjusted by adding elements such as Be, Mg, Ca, Sr, and Ba. In addition, even if unavoidable impurities such as H, N, O, and S are contained to such an extent that desired characteristics are not deteriorated, the composition can be regarded as the same as the composition of the high saturation magnetic flux density Fe-based soft magnetic alloy of the present invention. Of course.

In one of the alloys used in the present invention, Fe,
The Co content b is 92 atomic% or less. This is because b is 92
This is because a high magnetic permeability cannot be obtained if the atomic percentage exceeds 10%, but in order to obtain a saturation magnetic flux density of 10 kG or more, b must be 7 or more.
More preferably, it is at least 5 atomic%. In the alloy system not containing the element T'z, the amount b of Fe, Co, and Ni is set to 93 atomic% or less in order to obtain a high saturation magnetic flux density.

The saturation magnetic flux density of the alloy is usually 10 kG
There are many of the above, but for a low-frequency transformer, a transformer having a capacity of 13 kG or more is particularly preferable for downsizing the transformer.

The alloy is obtained by quenching an amorphous alloy or a crystalline alloy containing an amorphous phase having the above-mentioned composition from a molten metal, and heating the obtained alloy to form fine crystal grains. It can usually be obtained by a precipitation step.

Here, one method for obtaining a ribbon of the alloy having the above composition will be described based on a single roll liquid quenching method.

First, a molten metal is jetted from a nozzle of a crucible placed on one rotating steel roll onto the roll by a pressure of argon gas or the like, and rapidly cooled to obtain a ribbon. According to this method, the width is about several tens of mm and the thickness is 20-4.
A ribbon of about 0 μm can be obtained. Once the ribbon is obtained, an insulating layer made of MgO or the like is formed on the ribbon by a conventional method such as electrophoresis, thermal spraying, sputtering, or vapor deposition, and the insulating layer is placed inside the ribbon. Is wound, the magnetic core 1 shown in FIG. 2 can be obtained.

Next, the magnetic core 1 is heated to a temperature of 500 to 700 ° C.
By holding for a time, rapidly cooling by a method such as water quenching, and then annealing, the Fe-based soft magnetic alloy constituting the magnetic core 1 is crystallized. By crystallization in this way,
The magnetic properties and heat resistance are improved, and the desired magnetic core 1 can be obtained.

The low frequency transformer obtained as described above is
It is made of an Fe-based soft magnetic alloy that shows high saturation magnetic flux density and high magnetic permeability, so it exhibits excellent magnetic properties. In addition, the alloy itself is heat-treated at a temperature of 500 ° C or more, so it is naturally heat-resistant. Also excellent in nature.

Therefore, a transformer suitable for a power distribution transformer used at a commercial frequency or an inverter transformer used at a low frequency can be obtained.

[0046]

【Example】

(Production Example 1) A soft magnetic ribbon having a composition of Fe ₉₀ Zr ₇ B ₂ Cu ₁ and having a thickness of 20 μm and a width of 50 mm was coated with an insulating layer of MgO having a thickness of 1 μm to form a ribbon. The ribbon was wound to form a ring-shaped magnetic core having a height of 200 mm and a width of 100 mm. The magnetic core was heated to 600 ° C. for 1 hour in an N ₂ gas atmosphere, and then cooled to room temperature at a cooling rate of 100 ° C./min.

A transformer having the structure shown in FIG. 1 was prepared by using two heat-treated cores and winding a conductive wire between them as shown in FIG. The saturation magnetic flux density Bs of this transformer is 16.7 kG, the squareness ratio Br / Bs is 80%,
The coercive force Hc was 30 MOe, and the saturation magnetostriction constant was 5 × 10 ⁻⁶ , which was an excellent value of 1 × 10 ⁻⁵ or less, which is the value of a conventional Fe-based amorphous alloy for a power distribution transformer. Also,
Iron loss at 50 Hz and Bm of 12 kG is 0.10 W / k.
g, which proved to be an excellent value.

(Production Example 2) A molten alloy having the composition shown in Table 1 was quenched by a single roll method to produce an alloy ribbon having a width of 25 mm and a thickness of 18 μm.

Next, this alloy ribbon was subjected to an outer diameter of 40 mm and an inner diameter of 3 mm.
It was wound to 5 mm to obtain a toroidal core, and the same heat treatment as in Production Example 1 was performed. The alloy after heat treatment is 100-20
Ultrafine crystal grains having a particle size of 0 Å or less occupied most of the structure.

Next, this magnetic core is placed in a core case, and the primary side and the secondary side are wound for 250 turns on each side.
The iron loss at z and 12 kG was measured. Table 1 shows the obtained results.

[0051]

[Table 1]

As is clear from Table 1, the transformer according to the present invention has a saturation magnetic flux density of 1 for the soft magnetic alloy used for the magnetic core.
Since it is 4.6kG or more, the size of the transformer can be reduced.
The measurement was performed under the conditions of a frequency of 50 Hz and a magnetic flux density of 12 kG.
Since the iron loss was 0.22 W / kg or less, the iron loss was lower than that of a conventional transformer made of silicon steel, and it became clear that the iron loss was suitable for a columnar transformer, a low-frequency inverter transformer, and the like.

[0053]

As described above, according to the present invention, since it is made of a soft magnetic alloy having a special composition, it is suitable for a power distribution transformer used in a commercial frequency, an inverter transformer used in a low frequency range, and the like. This has the effect of providing a transformer having high saturation magnetic flux density, low iron loss, and excellent heat resistance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a low-frequency transformer of the present invention.

FIG. 2 is a perspective view showing one embodiment of a magnetic core of the low-frequency transformer of the present invention.

FIG. 3 is a graph showing a relationship between a cooling rate and a magnetic permeability.

[Explanation of symbols]

 1 Magnetic core 2 Conductor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Masumoto 3-8-22 Uesugi, Aoba-ku, Sendai, Miyagi Prefecture (72) Inventor Akihisa 35-35 Kawachimoto Hasekura, Aoba-ku, Aoba-ku, Miyagi Prefecture 11-806 (56) References JP-A-1-242755 (JP, A) JP-A-1-294847 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01F 1/153 C22C 38 / 00 H01F 27/24

Claims (3)

(57) [Claims] 1. A high saturation magnetic flux density Fe-based soft magnetic alloy having a composition represented by the following formula and having a saturation magnetic flux density of 14.6 kG or more and a conductive wire: a frequency of 50 Hz and a magnetic flux density of 12 kG.
A low-frequency transformer having an iron loss in G of 0.22 W / kg or less. (Fe1-aCoa) b BxTyT'z where T is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Mo, W, and Z
r, Hf, or both, and T ′ is Cu, Au
One or two elements selected from the group consisting of: a ≦ 0.05, 84 at% ≦ b ≦ 92 at%, x = 0.5 to
8 atomic%, y = 4 to 10 atomic%, and z = 4.5 atomic% or less. 2. A high saturation magnetic flux density Fe-based soft magnetic alloy having a saturation magnetic flux density of 14.6 kG or more having a composition represented by the following formula and a conductive wire, a frequency of 50 Hz and a magnetic flux density of 12 kG.
A low-frequency transformer having an iron loss in G of 0.22 W / kg or less. FebBxTyT'z where T is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Mo, W, and Z
r, Hf, or both, and T ′ is Cu, Au
One or two elements selected from the group consisting of: 84 atomic% ≦ b ≦ 92 atomic%, x = 0.5 to 8 atomic%, y =
4 to 10 atomic% and z = 4.5 atomic% or less. 3. The method according to claim 1 , wherein the insulating layer made of MgO is formed.
Wound thin ribbon of high saturation magnetic flux density Fe-based soft magnetic alloy
Low-frequency transformer according to with a magnetic core composed of Te in claim 1 or claim 2, characterized in.