JP2817965B2 - High frequency wound core - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wound core, and more particularly, to a wound core made of an amorphous alloy used under excitation in a high-frequency region exceeding 10 kHz.

[Conventional technology]

The manufacturing method of amorphous alloy with ribbon shape includes
A single-roll method, in which a synthetic liquid heated above the liquidus temperature is ejected from a nozzle onto a high-speed rotating copper cooling roll and cooled and solidified, and a gap between a pair of copper cooling rolls rotating at high speed in opposite directions to each other. A twin-roll method in which a synthetic liquid is jetted out and quenched and solidified may be mentioned, but a single-roll method is industrially adopted. When manufactured by the one-roll method, the amorphous alloy ribbon has a roll surface that has been quenched and solidified by contact with the cooling roll, and a free surface on the opposite side.

Conventionally, as a wound core using an amorphous alloy ribbon by the single roll method, as described in Japanese Patent Publication No. 58-41649, `` Magnetostriction of amorphous magnetic alloy ribbon having a positive characteristic A wound magnetic core characterized by being wound with a high surface (roll surface) inside is known.

[Problems to be solved by the invention]

By the way, high frequency transformer, core for noise filter,
Demands for use of smoothing choke coils, cores for mag amplifiers, and the like in the high-frequency region are increasing year by year with the demand for miniaturization and high efficiency of electronic devices such as switching power supplies. In particular, applications for use at frequencies exceeding several tens of kHz are increasing remarkably.

In this regard, the one described in Japanese Patent Publication No. 58-41649 does not describe the above-mentioned frequency range, and in the examples, only effects at low frequencies of 100 Hz, 1 kHz, and 10 kHz to medium frequencies were confirmed by experiments. No studies have been made on frequencies exceeding 100 kHz required this time.

An object of the present invention is to provide an amorphous alloy wound core that can be used effectively in a high frequency region exceeding, for example, 10 kHz, in order to solve the problems of the conventional technology.

[Means for solving the problem]

In order to solve the above-described problems, the wound core of the present invention is manufactured by a single roll method in which a synthetic liquid is supplied onto a cooling roll and quenched and solidified. This is a core for super 10 kHz formed by winding an amorphous alloy ribbon having a roll surface and a free surface on the opposite side with the roll surface side facing outward.

 Hereinafter, the present invention will be described in more detail.

Amorphous alloy utilized in wound magnetic core of the present invention, for example, _{(Fe (1-x-y} -z) Ni x Co y M z) (1-a-b-c)
More preferably, it is an amorphous magnetic alloy substantially represented by a composition formula represented by Si _a B _b C _c (A).

Here, M is one or a combination of two or more elements selected from the group consisting of Mo, Nb, and Cr, and the composition ratio of each element is 0 ≦ x ≦ 0.56 0 ≦ y ≦ 0.45 0 ≦ z ≦ 0.110 ≦ a ≦ 0.15 0.05 ≦ b ≦ 0.25 0 ≦ c ≦ 0.05 where 0.7 ≦ (1-abc) ≦ 0.9.

Here, nickel is an element that can improve the magnetic permeability, but when the content exceeds 50 at.% Of the whole, the saturation magnetic flux density drops significantly, and the Curie temperature of the alloy falls below room temperature. The value of 0 ≦ x ≦ 0.56 is preferable because the utility value is lost as a material.

As the content of the cobalt element increases, the saturation magnetization increases. However, when the content exceeds 40 at.%, The saturation magnetization decreases conversely, and the soft magnetic properties deteriorate. Therefore, 0 ≦ y ≦ 0.45 is preferable.

M is composed of at least one of Mo, Nb, and Cr, and these are high melting point metals. In particular, Mo, Nb, and Cr reduce the magnetostriction, increase the crystallization temperature, and significantly improve the soft magnetic properties. However, if the proportion of M exceeds 10 at.%, The saturation magnetic susceptibility decreases, and the Curie temperature also decreases, which is not practically preferable. In that case, the melting temperature (melting point) and the viscosity also increase, which is unsuitable for industrial mass production. Therefore, 0 ≦
It is preferable that z ≦ 0.11.

Next, the silicon element improves the soft magnetic properties such as the magnetic permeability and the ability to form an amorphous. When the proportion exceeds 15 at.%, On the contrary, the properties and performance deteriorate, so that 0 ≦ a ≦
It was set to 0.15.

Although boron element is indispensable for amorphous formation, it does not make sense to add more than 25 at.%.
b ≦ 0.25 is preferred.

Finally, the carbon element improves soft magnetic properties such as squareness, but the addition of 5 at.% Or more also reduces the magnetic properties, amorphous type performance and mechanical strength, so that 0 ≦ c ≦ 0.05.
It is preferable that

In the present invention, for example, an amorphous alloy represented by the above compositional formula occupying at least 98% by weight or more of the amorphous alloy is desirable.

In the present invention, the winding state of the amorphous alloy ribbon is formed in a spiral shape with the roll surface side facing outward. As the amorphous alloy ribbon used in this manner, it is generally preferable to wind an alloy ribbon manufactured by a single roll method.

That is, first, a mixed melt of, for example, the metal of the above composition (A), which has been heated to a melting point or more and is in a molten state, is ejected from a nozzle to collide with a cooling roll surface rotating at a high speed,
The melt is rapidly solidified on the roll surface to produce an amorphous alloy ribbon used in the present invention.

According to such a method, an amorphous alloy ribbon having both the roll surface quenched by the cooling roll and the free surface corresponding to the opposite surface is formed.

Next, such an amorphous alloy ribbon is wound into a magnetic core.

A magnetic core obtained by such a method can generally provide a magnetic core having excellent soft magnetic properties.

Subsequently, the magnetic cores thus obtained are each heat-treated at a specific optimum temperature of 300 to 600 ° C. to improve the soft magnetic properties. The heat treatment is preferably performed in an inert environment or an oxidizing environment, for example.

By the way, the description of JP-B-58-41649 states that "the surface in contact with the cooling roll has low gloss and good surface accuracy (smoothness ± 3μ), and the free surface has more gloss and poor surface accuracy ( Smoothness is ± 7μ), and the surface of the amorphous magnetic alloy white belt is wound with the surface with high smoothness on the inside and the free surface with irregularities is wound on the outside. It is thought that the anisotropy associated with the stress is reduced and the iron loss can be reduced, as compared to the case where the lower surface is wound inside. .

However, in allied signal products that have already been manufactured industrially, the scale-like surface undulations seen in the past and the streaky undulations in the longitudinal direction of the ribbon have almost completely disappeared. Even when measured using a surface roughness meter, the smoothness of both the free surface and the roll surface is 1 μ or less, and there is no significant difference in smoothness between the two. Further, when observed more finely, the roll surface may have a crack larger than the undulation of the free surface due to air entrainment at the time of production, and the roll surface is often worse in smoothness.

For this reason, the hypothesis described in JP-B-58-41649 cannot explain the difference in magnetic properties depending on the winding. Therefore, the following hypothesis is considered more appropriate.

As shown in FIG. 1, even in the same amorphous state, a difference in density occurs due to a difference in quenching speed. Naturally, the roll surface has a higher cooling rate, and the cooling rate decreases as approaching the free surface. Therefore, the solidified density is the lowest on the roll surface and the highest on the free surface. In other words, the free volume existing between the atoms on the roll surface side is the largest, and the free volume on the free surface side is the smallest. By the heat treatment, the amorphous alloy undergoes structural relaxation, the free volume disappears, and the volume shrinks. By performing sufficient heat treatment, the amount of shrinkage on the roll surface side, which has a large free volume, increases, so if the free surface is wound outside and heat treatment is performed, a slight tension is generated in the longitudinal direction of the ribbon. Is slightly compressed when wound outward. In the case of tension, a stripe-shaped axial structure is generated by the action of magnetostriction, whereas in the case of compressive force, a 90-degree domain wall is generated and the magnetic domain is subdivided.

In a Fe-based amorphous alloy, in a magnetic domain structure subdivided by 90-degree domain walls, eddy current loss is reduced, so that magnetic characteristics at high frequencies are excellent. On the other hand, the magnetic domain structure in the form of a stripe has excellent magnetic properties at low frequencies, but the large magnetic domains increase the eddy current loss and deteriorate the high-frequency magnetic properties. From the above, it is considered that in the present invention, by winding the roll surface outward, a wound core having excellent characteristics at high frequencies can be obtained.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

<Example 1> (US) METGLAS2 manufactured and sold by Allied Signal
Purchased 605S-2 (catalog composition Fe ₇₈ B ₁₃ Si ₉ at.%)
Outer diameter 25mm x inner diameter 15mm x height with ribbon roller surface outward
Ten pieces were wound in the shape of a 10 mm toroidal core. Weight is 20
g.

Subsequently, the thus-formed toroidal core was heated in a nitrogen gas atmosphere at 425 ° C. for 3 hours to obtain a magnetic core.

<Comparative example 1> It carried out similarly to Example 1 except having wound up with the free surface outside.

<Comparative experiment 1> Magnetic flux density using the magnetic core of Example 1 and the magnetic core of Comparative example 1
Iron loss was measured at 0.1 Tesla.

Iron loss is measured from 1 kHz to 20 using a Norma U function meter.
The measurement was performed between 0 kHz. 10 in Table 1 (see end of this section)
The average of the cores is listed.

As is evident from Table 1, the core wound with the roll surface outside is inferior in characteristics at the low frequency side to the core wound outside the free surface, but conversely exhibits excellent characteristics at the high frequency side exceeding 10 kHz. Recognize. It is more pronounced at higher frequencies.

Using a YHP LCR meter 4192A, the magnetic permeability was measured at a magnetic field amplitude of 5 mOe in the frequency range of 1 kHz to 2 MHz. Table 2 shows the average value of 10 cores.

From Table 2, it was confirmed that the characteristics of the core wound on the outer side of the roll surface were improved even in the high-frequency region exceeding 10 kHz.

<Example 2> (US) METGLAS2605S-3A manufactured by Allied Signal (composition
Fe _77.1 Co _0.1 Cr ₂ B ₁₆ Si _4.8 at.
The procedure was the same as in Example 1 except for the above.

<Comparative Example 2> The same operation as in Example 2 was performed except that the film was wound with the free surface facing outward.

<Comparative Experiment 2> The same operation as in Comparative Experiment 1 was performed except that the magnetic core of Example 2 and the magnetic core of Comparative Example 2 were used.

 Table 3 shows the average results of the five cores.

<Example 3> (US) METGLAS2605SC (composition Fe ₈₁ B _13.5 Si _3.5 C ₂ at.%) Manufactured by Allied Signal Co., Ltd. and the heating temperature was 380.
The procedure was the same as in Example 1 except that the heating time was 2 hours.

<Comparative Example 3> The same operation as in Example 3 was performed except that the film was wound with the free surface facing outward.

<Comparative Experiment 3> The same operation as in Comparative Experiment 1 was performed except that the magnetic core of Example 3 and the magnetic core of Comparative Example 3 were used.

 Table 4 shows the average results of the five cores.

<Example 4> (U.S.A.) The heating temperature was set to 4 using METGLAS2605SM (composition Fe _73.5 Ni ₄ Mo ₃ B _17.5 Si ₂ at.%) Manufactured by Allied Signal.
Example 1 was repeated except that the heating time was 40 ° C. and the heating time was 4 hours.

<Comparative Example 4> The same operation as in Example 4 was performed except that the winding was performed with the free surface facing outward.

<Comparative experiment 4> The same operation as in comparative experiment 1 was performed except that the magnetic core of Example 4 and the magnetic core of Comparative example 4 were used.

 Table 5 shows the average results of the five cores.

<Example 5> (US) Allied Signal's METGLAS2605Co (composition Fe ₆₇ Co ₁₈ B ₁₄ Si ₁ at.%) Was used at a heating temperature of 340.
The procedure was the same as in Example 1 except that the heating time was 2 hours.

<Comparative Example 5> The same operation as in Example 5 was performed except that the film was wound with the free surface facing outward.

<Comparative Experiment 5> The same operation as Comparative Experiment 1 was performed except that the magnetic core of Example 5 and the magnetic core of Comparative Example 5 were used.

 Table 6 shows the average results of the five cores.

As described above, even in Fe-based amorphous alloys having different compositions as shown in Examples 2 to 5, it can be confirmed that the soft magnetic properties are significantly improved by winding the roll surface outward from around 10 kHz. Was.

[Effects of the Invention] According to the present invention, it is possible to obtain an amorphous alloy wound core that has small iron loss and can be used effectively even in a high-frequency region exceeding 10 kHz.

[Brief description of the drawings]

 FIG. 1 is a diagram showing the relationship between temperature and alloy volume.

Claims (2)

(57) [Claims] (1) A single-roll method in which a combined liquid is supplied onto a cooling roll to quench and solidify, so that the roll surface contacted with the cooling roll and quenched and solidified, and the free surface on the opposite side. A high frequency core for use at super 10 kHz formed by winding an amorphous alloy ribbon having the roll surface side outside. Wherein the amorphous alloy, substantially following formula _{(A), (Fe (1} -x-y-z) Ni x Co y M z) (1-a-b-c)
Si _a B _b C _c [In the above formula (A), M represents one kind or a combination of two or more kinds of elements selected from the group consisting of Mo, Nb, and Cr. ≤ x ≤ 0.56, 0 ≤ y ≤ 0.45, 0 ≤ z ≤ 0.11, 0.7 ≤ (1-abc) ≤ 0.9, 0 ≤ a ≤ 0.15, 0.05 ≤ b ≤ 0.25, 0 ≤ c ≤ 0.05 The super 10 kHz according to claim 1, which is an amorphous magnetic alloy represented by the following formula:
Core for z.