JPH06163235A - Transformer - Google Patents

Abstract

PURPOSE:To contrive the high permeability and low iron loss of a magnetic material in the high-frequency region (the region of-MHz) of a power supply, whereby to use a transformer even when a high frequency power supply is used by a method wherein an amorphous alloy thin strip having a plate thickness formed thin in a specified dimension or smaller is used for the magnetic material. CONSTITUTION:A magnetic material is formed into an amorphous alloy, which is substantially shown by a general formula: (CO1-aAa)100-bXb (In the formula, the A shows at least one kind of an element which is chosen from among Fe, Mn, Ti, V, Cr, Ni, Cu, Zr, Nb, Mo, Hf, Ta, W and group platinum elements, the X shows at least one kind of an element which is chosen from among Si, B, P and C, the (a) shows a number to satisfy the condition of <=a<=1 in the case where the A contains the Fe and shows a number to satisfy the condition of 0<=a<=0.2 in the case where the A does not contain the Fe and the (b) shows a number to satisfy the condition of 10at%<=b<=35at%.). This alloy is formed into a wound material or a laminated material consisting of a soft magnetic alloy strip having a plate thickness of 10mum or thinner. Thereby, it becomes possible to inhibit the loss of the magnetic material as small as possible also in the high-frequency region of a power supply, a transformer can be used to even when a high frequency power supply is used and at the same time, it is also possible to contrive a miniaturization, a lightening and the like of the transformer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a high magnetic permeability in a high frequency range.
The present invention relates to a transformer that requires low loss.

[0002]

2. Description of the Related Art In recent years, with the demand for smaller and lighter electronic devices and higher performance, magnetic components used as important functional parts are also required to have higher performance.
Therefore, the magnetic materials used for these magnetic parts are also required to have excellent magnetic properties.

For example, a switching power supply has been widely used in recent years as a stabilizing power supply for electronic equipment. However, as the demand for smaller and lighter power supplies increases, higher switching frequencies are required. However, for example, in the case of a switching power supply incorporating a magnetic amplifier, even if an amorphous alloy with good high-frequency characteristics is used among the metal materials, the limit is practically 200 kHz to 500 kHz, and further higher frequencies are required. Was wanted.

Similarly, it is required for the power supply transformer to cope with higher frequencies. Here, ferrite occupies most of the materials currently used for the transformer. However, the transformer using ferrite has a problem that such requirements cannot be sufficiently satisfied. Therefore, the use of amorphous alloys in transformers has also been investigated.However, even if amorphous alloys that can obtain low iron loss and high squareness ratio in the high frequency range are used, iron loss increases in the MHz range. Practically, it is limited to about 500kHz.

On the other hand, it is generally known that by reducing the plate thickness of a metal material, iron loss can be suppressed and high-frequency characteristics can be improved, and reduction of the thickness of an amorphous alloy has also been studied. . Here, the amorphous alloy ribbon is generally produced by a liquid quenching method using a single roll method or the like, but there is a problem that the plate thickness cannot be sufficiently thinned by an ordinary liquid quenching method. .
Moreover, the amorphous alloy ribbon, whose thickness was reduced by the normal liquid quenching method, has a relatively large number of pinholes due to the inclusion of bubbles, etc. There was a problem in terms.

[0006]

As described above, magnetic materials for various magnetic cores are required to have high magnetic permeability and low iron loss up to a high frequency range (up to MHz range), and these are highly efficient devices. Downsizing, downsizing and weight reduction, downsizing of the magnetic core, and higher performance. Therefore, it has been strongly desired to reduce the iron loss in the high frequency range of the power source transformer in order to cope with the high frequency of the power source and to improve the efficiency and the size and weight of the transformer itself.

The present invention has been made in order to solve the above-mentioned problems, and it has been proposed that the high frequency range (.
It is an object of the present invention to provide a transformer capable of achieving high magnetic permeability and low iron loss in a frequency range), thereby making it possible to cope with high frequency power supply.

[0008]

[Means and Actions for Solving the Problems] The transformer of the present invention has a general formula: (Co _1-a A _a ) _100-b X _b (1) (where A is Fe, Mn, Ti , V, Cr, Ni, Cu, Zr, Nb, M
o, Hf, Ta, W, and at least one element selected from the platinum group elements, X represents at least one element selected from Si, B, P, and C, and a represents when A contains Fe. Is 0 ≤ a ≤ 1 and 0 ≤ a ≤ 0.2 when A does not contain Fe
And b is a number that satisfies 10at% ≤ b ≤ 35at%. The same shall apply hereinafter) consisting essentially of an amorphous alloy,
In addition, it is characterized by comprising a wound body or a laminated body of a soft magnetic alloy ribbon having a plate thickness of 10 μm or less.

That is, the transformer of the present invention is a pin-ho
The plate thickness is 10μ while maintaining a good condition
By using an amorphous alloy ribbon thinned to m or less, it is possible to cope with high frequency power supply. In other words, the transformer using the amorphous alloy ribbon with a plate thickness of 10 μm or less can suppress the loss as much as possible even in the high frequency range (to MHz range), and it is possible to cope with higher frequency power supply. The size and weight of the device itself can be reduced.

The amorphous alloy used in the present invention is
Basically, it has a composition represented by the above formula (1). The element A in the above formula (1) is an element effective for improving thermal stability and magnetic properties. Here, when Fe is contained as the A element, the value of a is in the range of 0 to 1. That is, the amorphous alloy used in the present invention includes a Fe-based amorphous alloy in addition to the Co-based amorphous alloy. However, it is preferable to use a Co-based amorphous alloy from the viewpoint of characteristics. Further, X is an essential element for amorphization, and if the amount of X (value of b) is less than 10 atom% or exceeds 35 atom%, it becomes difficult to amorphize.

Among the amorphous alloys used in the present invention, the Co-based amorphous alloy is as follows (2)
It is preferable that the composition is substantially represented by the formula.

General formula: (Co _1-c M _c ) _100-b X _b (2) (wherein M is Ti, V, Cr, Fe, Mn, Ni, Cu, Zr, Nb, M
o, Hf, Ta, W, and at least one element selected from platinum group elements, X represents at least one element selected from Si, B, P, and C, and c is 0 ≦ c ≦ 0.5 (however, , M is a number that satisfies 0 ≤ c ≤ 0.2) when Fe and Ni are excluded. The same shall apply hereinafter) In the above formula (2), M element is an element effective for improving thermal stability and magnetic properties, and Ti, V, Cr, Cu, Zr, Nb,
When selected from Mo, Hf, Ta, W and platinum group elements, the value of c, which represents the substitution amount by this M element, is preferably 0.2 or less. If the value of c exceeds 0.2, the Curie temperature decreases, which is not practical. For Fe and Ni,
The value of c is preferably 0.5 or less. At this time, when the value of c exceeds 0.5, the effect of improving the magnetic properties decreases conversely.

Further, when particularly excellent high frequency characteristics are required, the general formula: (Co _{1-de M'd} M " _e ) _100-g (Si _1-f B _f ) _g ..... (3 (In the formula, M'is at least one element selected from Fe and Mn, and M "is Ti, V, Cr, Ni, Cu, Zr, Nb, Mo, Hf, T
a, W and at least one element selected from platinum group elements, d is 0.03 ≤ d ≤ 0.15, e is 0 ≤ e ≤ 0.10
, F is 0.2 ≦ f ≦ 1.0, and g is a number satisfying 10at% ≦ g ≦ 35at%. It is preferable to use a Co-based amorphous alloy substantially represented by the following).
In the composition represented by the above formula (3), the value of g is more preferably in the range of 20 at% to 35 at% and the value of f is more preferably in the range of 0.3 to 0.8 in consideration of thermal stability of magnetic properties.

The plate thickness used in the transformer of the present invention is 10 μm.
An amorphous alloy ribbon of m or less can be obtained with good reproducibility by applying the manufacturing method described below.

That is, when the amorphous alloy ribbon is produced by jetting the molten alloy from the nozzle onto the surface of the rotary cooling body and super-quenching, the atmosphere during which the molten alloy jetted from the nozzle contacts the rotary cooling body. Is an inert atmosphere of less than 60 Torr or a reduced pressure atmosphere of 0.01 Torr or less.

Specifically, the quartz nozzle containing the mother alloy is evacuated to a pressure of 0.01 Torr or less, or the inert gas is replaced to 60 Torr or less. In the case of a base amorphous alloy, a Fe-based roll or a Cu-based roll (brass or the like) can be used to produce an excellent ultrathin amorphous alloy ribbon with few pinholes.

Here, the reason why the reduced pressure or the inert gas atmosphere is set to 0.01 Torr or less or 60 Torr or less is that the thin and excellent surface property is achieved and the pinhole is excellent especially when a wide ribbon of 1.5 mm or more is produced. This is because the occurrence of such a phenomenon is extremely small, and waviness (unevenness) occurs in the width direction, there are many pinholes, or a ribbon of 10 μm or less cannot be obtained outside this range. The inert gas used is preferably He or Ar, and
Is most preferred.

As described above, the roll material is preferably a Fe-based alloy or a Cu-based alloy when producing a Fe-based amorphous ultrathin ribbon, and when producing a Co-based amorphous ultrathin ribbon. Fe-based alloys are preferable, and by using these in combination, those having good surface properties and extremely thin plates can be obtained.

Further, the long side in the slit shape at the tip of the nozzle determines the width of the obtained ribbon, and is 2 mm.
The above appropriate values can be set. The short side is an important value that determines the plate thickness of the ribbon, and is preferably 0.2 mm or less, and more preferably 0.15 mm or less for producing an ultrathin ribbon. The roll peripheral speed may be 10 m / sec or more, preferably 20 m / sec or more. Injection pressure is 0.05kg / cm for making ultra-thin ribbon
² or more, preferably 0.025 kg / cm ² or less, more preferably 0.020 kg / cm ² or less, 0.00
If it is less than 1 kg / cm ² , it becomes difficult to inject molten metal.

The magnetic core used in the transformer of the present invention is formed into a desired shape by winding the ultrathin amorphous alloy ribbon obtained by the above-described manufacturing method or by laminating one or more layers, It can be obtained by heat treatment while applying a magnetic field in a direction substantially perpendicular to the excitation direction. In the range of compositions where the crystallization temperature is higher than the Curie temperature, it is necessary to perform strain relief heat treatment at a temperature not higher than the crystallization temperature but not lower than the Curie temperature on the wound body or laminated body before the magnetic field heat treatment. There is. Specifically, this magnetic field heat treatment is performed while applying a magnetic field to the wound magnetic core in the ribbon width direction and to the laminated magnetic core in the radial direction. The transformer of the present invention is obtained by applying a desired winding to the magnetic core.

The above-mentioned magnetic field heat treatment imparts magnetic anisotropy in a direction substantially perpendicular to the exciting direction of the obtained magnetic core, whereby the squareness ratio is appropriately lowered,
It is possible to prevent magnetic saturation on the low magnetic field side. Therefore, it is possible to obtain a transformer having good characteristics even on the high magnetic field side. The applied magnetic field strength in the magnetic field heat treatment may be 1 Oe or more, preferably 10 Oe
Or more, more preferably 50 Oe or more. The atmosphere for these heat treatments is not particularly limited, and may be any of an inert atmosphere such as nitrogen and argon, a vacuum, a reducing atmosphere such as hydrogen, and the atmosphere.

[0022]

EXAMPLES Examples of the present invention will be described below.

Example 1 An alloy composition of Co _70.3 Fe _4.7 Si ₁₅ B ₁₀ was prepared and melted to obtain a mother alloy for producing an amorphous alloy. The nozzle shape used had a slit of 5 mm × 0.15 mm, Fe was used as the roll material for the production of the amorphous alloy, the single roll device was put in the chamber, and after preliminary vacuum exhaust to 5 × 10 ^-5 Torr, He gas Was sealed up to 30 Torr. When the roll peripheral speed was 57 m / sec, the injection gas pressure was 0.02 kg / cm ² , and the molten metal was ultra-quenched in the above inert atmosphere, it had a good surface property and had a plate thickness of 8.4 μm and a width of 4.8 mm. A very thin amorphous alloy ribbon was obtained.

Next, after winding the ultrathin amorphous alloy ribbon, optimum heat treatment (strain relief heat treatment) is performed, and then
250 ℃ × while applying 1kOe magnetic field across the width of the ribbon
Magnetic field heat treatment was performed for 1 hour to obtain the target transformer core.

When the iron loss of the magnetic core for a transformer thus obtained was measured in a high frequency region, a good value of 1 W / cc was obtained under the conditions of 1 MHz and 0.1 T.

Further, as a comparison with the present invention, except that the molten metal is rapidly quenched in the atmosphere, under the same conditions, with the same composition, the plate thickness
When a 17 μm amorphous alloy ribbon was produced, wound in the same magnetic core shape and subjected to the same heat treatment, the iron loss under the same conditions was 5.8 W / cc.

The magnetic cores for transformers according to these examples and comparative examples were incorporated as a main transformer of a switching power supply operating at 1 MHz, and the operation characteristics were evaluated. The main transformer according to the examples showed an improvement in power supply efficiency of 3.0%. A decrease of 55 ° C was observed with the temperature rise of the magnetic core.

Examples 2 to 15 Co-based amorphous alloy ribbons having the respective compositions shown in Table 1 were changed in roll peripheral speed in the range of 30 m / sec to 50 m / sec, and other conditions were fixed as follows. It was made. That is, the nozzle shape is 5 mm × 0.15 mm, the roll material is Fe, and the quenching atmosphere is 10
^The pressure was reduced to ^-4 Torr, the injection pressure was 0.01 kg / cm ² , and the gap between the nozzle and the roll was 0.15 mm. The thickness of each Co-based amorphous alloy ribbon thus obtained is shown in Table 1.
It was as shown in. Also, each of these Co-based amorphous alloy ribbons is wound around an outer diameter of 12 mm x an inner diameter of 10 mm to form a magnetic core,
After subjecting these to strain-relieving heat treatment, heat treatment was carried out at a temperature below the Curie temperature for 1 hour while applying a magnetic field of 500 Oe in the width direction of the ribbon. In addition, Examples 3, 4, 10
In the above, the heat treatment for strain relief was not performed, and the heat treatment was performed at 250 ° C. for 1 hour while applying a magnetic field of 500 Oe in the width direction of the ribbon. Then, the iron loss of 1 MHz and 0.1 T was measured. Also, as in Example 1, the power supply efficiency when incorporated in a switching power supply and the temperature rise of the magnetic core during operation were evaluated.
The results are also shown in Table 1.

[0029]

[Table 1]

As is clear from Table 1, the main transformers according to the respective examples are effective in increasing the efficiency of the power supply. As Comparative Example 2, the same evaluation was performed on the main transformer using ferrite, but the efficiency was reduced.

[0031]

As described above, according to the present invention, it is possible to stably provide a transformer in which iron loss is reduced in a high frequency range (up to MHz range). Therefore, for example, it becomes possible to cope with the high frequency of the power source, and the industrial effect thereof is extremely large.

[0032]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01F 27/24

Claims (2)

[Claims] 1. A general formula: (Co _1-a A _a ) _100-b X _b (wherein A is Fe, Mn, Ti, V, Cr, Ni, Cu, Zr, Nb, M).
o, Hf, Ta, W, and at least one element selected from the platinum group elements, X represents at least one element selected from Si, B, P, and C, and a represents when A contains Fe. Is 0 ≤ a ≤ 1 and 0 ≤ a ≤ 0.2 when A does not contain Fe
, B is a number satisfying 10 at% ≤ b ≤ 35 at%) and is composed of an amorphous alloy substantially represented by
A transformer comprising a wound body or a laminated body of a soft magnetic alloy ribbon of 10 μm or less. 2. The transformer according to claim 1, wherein the amorphous alloy has the general formula: (Co _1-c M _c ) _100-b X _b (wherein M is Ti, V, Cr, Fe, Mn, Ni, Cu, Zr, Nb, M
o, Hf, Ta, W and at least one element selected from platinum group elements, X represents at least one element selected from Si, B, P and C, and c is 0 ≦ c ≦ 0.5 (however, , M is a Co-based amorphous alloy that is substantially represented by a number that satisfies 0 ≦ c ≦ 0.2) when Fe and Ni are excluded.