JP2812569B2 - 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 and 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 this background, the present inventors have previously developed a Fe-based soft magnetic alloy having a high saturation magnetic flux density and proposed it in Japanese Patent Application No. 2-108308.
A further application was filed for a patent on March 18, 1991.

[0007] The following four types are included in the alloy according to the patent application filed on March 18, 1991 . (1) (Fe _1-a Co _a ) b Bx Ly T'za ≦ 0.05, b ≦ 92 at%, x = 6.5 to 18 at%, y
= 4 to 10 atomic%, and z = 4.5 atomic% or less.

(2) FebBxLy T'zb ≦ 92 at%, x = 6.5 to 18 at%, y = 4 to 10 at%, and z = 4.5 at% or less.

(3) (Fe _1−a M _a ) bBx Ly a ≦ 0.05, b ≦ 93 at%, x = 6.5 to 10 at%, y
= 4 to 9 atomic%.

(4) FebBxLyb ≦ 93 at%, x = 6.5 to 10 at%, y = 4 to 9 at%.

[0011]

[0012]

[0013]

[0014]

(Where L is one or more elements selected from the group consisting of Ti, Nb and Ta, and T ′ is Cu, Ag,
One or more elements selected from the group consisting of Au, Ni, Pd, and Pt, and M is any of Co, Ni, or
Both . )

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 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]

Means for Solving the Problems In order to solve the above problems, the invention described in claims 1 and 2 is based on the following (1).
It comprises a high saturation magnetic flux density Fe-based soft magnetic alloy having the composition shown in (2) and a conductive wire.

[0019]

[0020]

(1) (Fe _1−a M _a ) b Bx Ly a ≦ 0.05, b ≦ 93 at%, x = 6.5 to 10 at%, y
= 4 to 9 atomic%.

(2) FebBxLyb ≦ 93 at%, x = 6.5 to 10 at%, y = 4 to 9 at%.

[0023]

[0024]

[0025]

[0026]

[0027] (wherein L is Ri least one element der selected from the group consisting Ti, Nb, from Ta, M is Co, Ni
Either or both. )

[0028]

Since a 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.

[0029]

FIG. 1 shows an embodiment of a transformer according to the present invention. The transformer T of this embodiment mainly comprises a pair of left and right magnetic cores 1 and a conductor 2 wound around the magnetic cores 1,1. Have been. As shown in FIG. 2, the magnetic core 1 is formed by winding a thin ribbon. The ribbon is composed of a soft magnetic alloy ribbon having a composition such as Fe ₈₀ Nb ₇ B ₁₂ 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 formulas (1) and (2) can be used.

[0031]

[0032]

(1) (Fe _1−a M _a ) b Bx Ly a ≦ 0.05, b ≦ 93 at%, x = 6.5 to 10 at%, y
= 4 to 9 atomic%.

(2) Fe b B x Ly b ≦ 93 at%, x = 6.5 to 10 at%, y = 4 to 9 at%.

[0035]

[0036]

[0037]

[0038]

[0039] (wherein L is Ri least one element der selected from the group consisting Ti, Nb, from Ta, M is Co, Ni
Either or both. )

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 by heating this to form fine crystal grains. Can usually be obtained by a heat treatment step.

In order to easily obtain an amorphous phase in the present invention, it is necessary to include at least one of Ti, Nb and Ta and B having an amorphous forming ability.

It is considered that B has the effect of increasing the ability of the alloy of the present invention to form an amorphous phase and the effect of suppressing the formation of a compound phase that adversely affects the magnetic properties in the heat treatment step. It is. As in B, A1, Si,
C, P and the like are also generally used as amorphous forming elements, and the case where these elements are added can be regarded as the same as the present invention.

Although Ti, Nb and Ta have the same effect,
Among these elements, Nb and Ta are metal materials having a high melting point, are thermally stable, and are hardly oxidized during production. Therefore, when these elements are added, the production conditions are easier and less expensive than the material (containing Hf or Zr) for which the present inventors previously applied for a patent in Japanese Patent Application No. 2-108308. Can be manufactured to
It is also advantageous in terms of cost. That is, in the case of a system alloy to which the present inventors previously applied for a patent in Japanese Patent Application No. 2-108308, it was necessary to supply an inert gas in a vacuum atmosphere and to manufacture the alloy while paying attention to oxidation. However, in the alloy of the present invention, manufacturing conditions can be reduced.
Specifically, it can be manufactured in the air or in an air atmosphere while partially supplying the inert gas to the nozzle tip.

[0044] Incidentally, Cu, Ni and at least one or more elements selected from among these and congener, 4.5 atomic% or less, more preferably 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 Cu, Ni, etc. become 0.2 atomic% or less,
Although the magnetic permeability tends to decrease, the saturation magnetic flux density tends to increase.

Although the mechanism by which the soft magnetic properties are significantly improved by the addition of Cu, Ni, etc. is not clear, the crystallization temperature was measured by differential thermal analysis.
The crystallization temperature of the alloy to which Cu, Ni or the like was added was recognized to be slightly lower than that of the alloy without addition. This is thought to be due to the fact that the amorphous phase became non-uniform due to the addition of the element, and as a result, 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 microcomposition fluctuations occur due to heating, and the tendency for the amorphous phase to become non-uniform becomes more prominent. It is considered that this contributes to the refinement of the structure.

In view of the above, Cu and its congeners, Ni
Similar effects can be expected for elements other than Pd and Pt that lower the crystallization temperature. Fe like Cu
The same effect can be expected for an element having a small solid solubility limit with respect to.

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 the corrosion resistance of other elements other than these elements, Cr, Ru are used.
Other platinum group elements can be added, and if necessary, Y, rare earth element, Zn, Cd, Ga, In, G
e, Sn, Pb, As, Sb, Bi, Se, Te, Li, Be, Mg, Ca, Sr,
The magnetostriction can be adjusted by adding an element such as 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.

Fe, C in one of the alloys used in the present invention
The amount b is 92 atomic% or less when no T ′ component is contained. This is because high magnetic permeability cannot be obtained if b exceeds 92 atomic%, but in order to obtain a saturation magnetic flux density of 10 kG or more, it is more preferable that b is 75 atomic% or more. Incidentally, in the alloy system not containing the T ′ component, F
e, Co and Ni amount b are 9 to obtain a high saturation magnetic flux density.
3 atomic% or less.

The saturation magnetic flux density of the alloy is usually 10 KG.
Although there are many of the above, for a low frequency transformer, a transformer having 13 KG or more is particularly preferable for downsizing the transformer.

The alloy is obtained by rapidly cooling an amorphous alloy having the above composition or a crystalline alloy containing an amorphous phase from a molten metal, and heating the resulting 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. When a 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 650 ° C.
The Fe-based soft magnetic alloy constituting the magnetic core 1 is crystallized by holding for a time, quenching by a method such as water quenching, and then annealing. 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 a Fe-based soft magnetic alloy that shows high saturation magnetic flux density and high magnetic permeability, so it exhibits excellent magnetic properties. In addition, since the alloy itself is heat-treated at a temperature of 500 ° C or more, it is naturally heat-resistant. Also excellent in nature.

Accordingly, a transformer suitable for a power distribution transformer used at a commercial frequency, an inverter transformer used at a low frequency, and the like can be obtained.

(Production Example 1) A soft magnetic ribbon having a composition of Fe ₈₀ Nb ₇ B ₁₂ Cu ₁ and having a thickness of 20 μm and a width of 50 mm was formed on a soft magnetic ribbon.
A thin ribbon is created by covering an insulating layer having a thickness of 1 μm
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 magnetic cores after the heat treatment and winding a conductive wire between them as shown in FIG. The saturation magnetic flux density Bs of this transformer is 14.1 kG, the squareness ratio Br / Bs is 80%, the coercive force Hc is 30 mOe, the saturation magnetostriction constant is 5 × 10 ^-6 , and a conventional Fe-based amorphous alloy for a power distribution transformer. Was an excellent value of 1 × 10 ⁻⁵ or less. Also, 5
The core loss at 0 Hz and Bm of 12 kG was 0.10 W / kg, which proved to be excellent.

(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 35 mm.
The heat treatment was carried out in the same manner as in Production Example 1 by winding into a toroidal core. In the alloy after the heat treatment, ultrafine crystal grains having a grain size of 100 to 200 angstroms or less occupy 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 each.
The iron loss at z and 12 kG was measured. Table 1 shows the obtained results.

[0062]

[Table 1]

As is apparent from Table 1, the transformer according to the present invention has lower iron loss than the conventional transformer made of silicon steel, and is suitable for a columnar transformer, a low-frequency inverter transformer, and the like.

[0064]

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 an embodiment of the present invention.

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

[Explanation of symbols]

1 core 2 conductor

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihisa Inoue 11-806 Kawauchi Residence No. Kawauchi, Aoba-ku, Sendai City, Miyagi Prefecture (56) References JP 1-2242755 (JP, A) JP 1 294847 (JP, A) JP-A-2-43348 (JP, A) JP-A-56-72153 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 1/153

Claims (2)

(57) [Claims] 1. A high saturation magnetic flux having a composition represented by the following formula:
Characterized by comprising a Fe-based soft magnetic alloy and a conducting wire
Low frequency transformer. (Fe _1-a  M _a ) b Bx Ly However, M is either Co or Ni, or both,
L is one or two selected from the group consisting of Ti, Nb, and Ta
Element a ≦ 0.05, b ≦ 93 at%, x = 6.5 to 10 at%, y
= 4 to 9 atomic%. 2. A high saturation magnetic flux having a composition represented by the following formula:
Characterized by comprising a Fe-based soft magnetic alloy and a conducting wire
Low frequency transformer. Fe b Bx Ly Where L is one selected from the group consisting of Ti, Nb and Ta, or
Two or more elements, b ≦ 93 at%, x = 6.5 to 10 at%, y = 4 to 9 atoms
%.