JPH09246034A - Magnetic core for pulse transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic core for a pulse transformer which is excellent in impedance frequency characteristics and transmission characteristics over a wide of temperature by making a height of the transformer to be 3mm or less, while requiring a less number of turns in coil winding. SOLUTION: The transformer magnetic core comprises a ring-shaped magnetic core body 3 made of magnetic material and resin coatings 1 and 2 covering the body 3. The magnetic core body 3 has an outer diameter of 10mm or less, a thickness of 1.2mm or less and an AL value of 4.0μ H/N<2> or more at 10kHz and at the time of an input of 0.1V. The magnetic core body 3 may comprise a wound soft magnetic alloy thin strip, laminated rings blanked by a press, or laminated E shaped and I shaped thin pieces blanked by pressing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse transformer magnetic core having excellent frequency characteristics of impedance and excellent pulse transmission characteristics.

[0002]

2. Description of the Related Art In recent years, in the field of electronic equipment, miniaturization, thinning, and high performance have been promoted.
In a pulse transformer for an interface such as an SDN (Integrated Digital Communication Network), it is necessary to satisfy electrical characteristics conforming to strict standards such as ITU-T Recommendation I.430. In the specification of electrical characteristics described in the above standard, the primary winding impedance of the pulse transformer is 10
1250 Ω at 100 kHz and 2500 Ω or more at 100 kHz are required.
0 mH and 4 mH. The output pulse voltage waveform is
It must fall within the range of the pulse mask described in the standard, and it is desired that the inductance value be as flat as possible with respect to frequency. On the other hand, for the pulse transformer, there is a strong demand for downsizing in order to mount it on a PC card or the like. For example, a PCMCIA card (one of the interface standard cards for notebook PCs)
In order to mount the card on the internal substrate of (Seed), since the thickness of the card itself is about 5 mm, the height of the pulse transformer is set to 3 m.
There are restrictions that must be set to m or less. The mounting area in this case is generally 14.0 mm × 14.0 mm.
mm or less.

[0003] From the above background, at present, high magnetic permeability ferrite is mainly used as the core material of a pulse transformer for ISDN, and the core shape of the transformer is an EI type or EE having a mirror-finished coupling surface. The type is used. The above-mentioned EI type magnetic core is obtained by abutting and integrating an E type core material and an I type core material, and forms a transformer by winding the E type core material. Further, the EE type magnetic core is an E type core material that is abutted and integrated so as to match each other.

[0004]

The high magnetic permeability ferrite currently used in the pulse transformer magnetic core for ISDN has a nominal initial magnetic permeability of 10,000 to 12,000, but the initial magnetic permeability of the ferrite depends on the temperature. It is known that there is a large variation, and that the value is about -40% of the nominal value near -20 ° C. Therefore, around -40 ° C to +100
In order to guarantee the operation of the pulse transformer in the temperature range near ℃, when using a ferrite core, there is a problem that the transformer must be designed with an initial permeability much lower than the nominal value. For this reason, in order to obtain the inductance required for the pulse transformer for ISDN, it is necessary to increase the effective sectional area of the magnetic core or increase the number of turns. However, if the number of turns is increased in the pulse transformer having the conventional structure, the leakage inductance increases, and it is inevitable that a portion of the winding coil having a potential difference (for example, the start and end of winding) approaches, resulting in an increase in stray capacitance. Will be. For this reason, the transmission frequency band of the transformer is narrowed, and the transmission fidelity of the waveform is deteriorated. On the other hand, if the effective area of the magnetic core is increased, there is a problem that the entire pulse transformer cannot be downsized. Therefore, even if an attempt is made to manufacture a pulse transformer having excellent transmission characteristics for ISDN with the above mounting area using a ferrite magnetic core, it is difficult to make the height of the transformer 3 mm or less. In some cases, the number of windings is set to 1 using a thin ferrite core.
It is also known that the minimum range of the required characteristics can be reached by increasing the number of turns to 00 or more. However, in this configuration, the number of windings is large, and the number of turns of 100 turns or less is required as described above. Could not be satisfied.

The present invention has been made in view of the above circumstances, and in order to realize a pulse transformer having excellent frequency characteristics of impedance and transmission characteristics in a wide temperature range, the height of the transformer is formed to 3 mm or less. Another object is to provide a pulse transformer that requires a small number of windings.

[0006]

In order to solve the above-mentioned problems, a pulse transformer magnetic core according to the present invention comprises an annular magnetic core body formed by laminating rings made of soft magnetic alloy ribbon having a plate thickness of 25 μm or less. The outer diameter of this annular magnetic core body is 10
mm or less, thickness 1.2 mm or less, AL at 0.1V input
The value is 4.0 μH / N ² or more at 10 kHz. In addition, an E-type core, an I-type core, and a U-type core obtained by laminating E-type flakes, I-type flakes, and U-type flakes obtained from a soft magnetic alloy ribbon having a plate thickness of 25 μm or less are configured,
The E core and the I core, the E core and the E core, the U core and the I core, or the U core and the U core are combined to form a magnetic core body, and the magnetic core body has a thickness. 1.2m
It is also possible to adopt a configuration in which the AL value at the time of inputting 0.1 V is 4.0 μH / N ² or more at 10 kHz when the voltage is m or less. It is preferable that the ring is filled with 50% or more of the resin coating. In the soft magnetic alloy ribbon, the absolute value of magnetostriction is preferably 1 × 10 ⁻⁶ or less.

Next, in the present invention, a soft magnetic alloy ribbon having a plate width of 1.2 mm or less and a plate thickness of 25 μm or less is wound to form an annular magnetic core body, and the outer diameter of the annular magnetic core body is 10 mm or less. It is also possible to characterize that the AL value at the time of 0.1 V input is 4.0 μH / N ² or more at 10 kHz. Further, in the temperature range of −40 ° C. to + 100 ° C., the variation of the AL value with respect to room temperature is within ± 20%, and the configuration described in any one of the above may be employed. The soft magnetic alloy is composed mainly of fine crystal grains having a body-centered cubic structure with 50% or more of its structure having an average crystal grain size of 30 nm or less, Fe as a main component, and Ti, Z
It may contain Si and / or B, and one or more elements selected from the group consisting of r, Hf, V, Nb, Ta, Mo and W.

Next, the soft magnetic alloy can be made to have a composition represented by the following formula. Fe _b B _x M _y However, M is Ti, Zr, Hf, V, Nb, Ta, Mo,
1 or 2 or more elements selected from the group consisting of W, and b, x, and y indicating the composition ratio are 75 ≦ b ≦ 93 atomic%,
0.5 ≦ x ≦ 18 atomic% and 4 ≦ y ≦ 9 atomic%. The soft magnetic alloy may have a composition represented by the following formula. Fe _{b B x} M _{y X Z} where, M is, Ti, Z
r, Hf, V, Nb, Ta, Mo, W is one or more elements selected from the group consisting of, X is Si, A
1 or 2 or more of 1, Ge, and Ga, and b, x, y, and z indicating the composition ratio are 75 ≦ b ≦ 93 at%, 0.5
≦ x ≦ 18 atomic%, 4 ≦ y ≦ 9 atomic%, and z is 4 atomic% or less. The soft magnetic alloy may have a composition represented by the following formula. Fe _{b B x} M _y T _d where, M
Is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W,
T is one or more elements selected from the group consisting of Cu, Ag, Au, Pd, and Pt, and indicates the composition ratio.
b, x, y and d are 75 ≦ b ≦ 93 atomic%, 0.5 ≦ x ≦ 18
Atomic%, 4 ≦ y ≦ 9 atomic%, and d is 4.5 atomic% or less. The soft magnetic alloy may have a composition represented by the following formula. _{Fe b B x M y T d} X Z However, M
Is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W,
T is one or more elements selected from the group consisting of Cu, Ag, Au, Pd, and Pt, and X is Si, A
1, b, x, y, d, and z, which represent one or two or more of l, Ge, and Ga, and have a composition ratio, are 75 ≦ b ≦ 93 atomic%,
0.5 ≦ x ≦ 18 atomic%, 4 ≦ y ≦ 9 atomic%, d is 4.5 atomic% or less, and z is 4 atomic% or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The pulse transformer magnetic core according to the present invention is realized, for example, in a toroidal shape. The magnetic core of such a toroidal pulse transformer is manufactured by a quenching method described below after manufacturing a soft magnetic alloy ribbon having the composition described below, and then the soft magnetic alloy ribbon is press-punched to obtain a ring. Laminated or formed by winding a soft magnetic alloy ribbon into an annular shape, and this magnetic core is coated with epoxy resin, for example, or sealed in a resin case for insulation protection and winding. A pulse transformer magnetic core is obtained with. Also, E
In order to realize an I-core type magnetic core, the soft magnetic alloy ribbon is punched into an E-shape or an I-shape by pressing to form a plurality of E-type thin pieces and I-type thin pieces, and then the E-type thin piece. I or I type thin pieces are laminated together to form an E type core and an I type
It can be obtained by making mold cores and joining them. In addition, these E-type cores and I-type cores are covered with a resin such as an epoxy resin for the necessary parts or inserted in a resin case to insulate and protect the necessary parts, and after winding, the side parts of the E-type magnetic core A pulse transformer magnetic core can be obtained by joining the side portions of the I-shaped magnetic core with each other. The magnetic core is E
The present invention is not limited to a combination of a die and an I-type core, and may be a magnetic core including any combination of an E-type core and an E-type core, a U-type core and an I-type core, and a U-type core and a U-type core. Absent.

FIGS. 1 and 2 show an example of a toroidal transformer structure. In the structure shown in FIG. 1, a soft magnetic alloy thin film is placed inside the upper case 1 and the lower case 2 which are divided into two upper and lower hollow circular rings. The magnetic core 3 having a laminated band of rings is housed, and in the configuration shown in FIG. 2, a soft magnetic alloy thin strip 5 is wound inside a similar upper case 1 and lower case 2, and the whole is coated with resin. The magnetic core 6 is housed to form a transformer. The upper case 1 and the lower case 2 may be appropriately used, and needless to say, the magnetic core may be formed only by resin coating.

As the soft magnetic alloy forming the soft magnetic alloy ribbon, Fe is a main component and Ti, Zr, Hf, V and N are contained.
It is preferable to use a structure that contains B and one or more elements selected from the group consisting of b, Ta, Mo, and W, and has a structure in which a large number of fine crystal grains are precipitated in an amorphous phase. Further, a soft magnetic alloy having a composition represented by the following formulas is particularly preferable. _{Fe b B x M y Fe b} B x M y X Z Fe b B x M y T d Fe b B x M y T d X Z where, M is, Ti, Zr, Hf, V , Nb, Ta, M
O is one or more elements selected from the group consisting of W, and T is one or more elements selected from the group consisting of Cu, Ag, Au, Pd, and Pt. , X
Is one or more of Si, Al, Ge, and Ga, and b, x, y, d, and z indicating the composition ratio are 75 ≦ b ≦ 9.
3 atom%, 0.5 ≦ x ≦ 18 atom%, 4 ≦ y ≦ 9 atom%, d
Is 4.5 atomic% or less and z is 4 atomic% or less. In the soft magnetic alloys having these compositions, the value of b indicating the amount of Fe added is 93 atomic% or less. This is because if b exceeds 93 atomic%, it becomes difficult to obtain an amorphous single phase by the liquid quenching method, and as a result, the structure of the alloy obtained after the heat treatment becomes non-uniform and high magnetic permeability is obtained. This is because they cannot be obtained. Further, in order to obtain a saturation magnetic flux density of 10 kG or more,
Since b is more preferably 75 atomic% or more, the range of b is preferably 75 to 93 atomic%.

Further, B has an effect of increasing the amorphous forming ability of the soft magnetic alloy, an effect of preventing the coarsening of the crystal structure, and an effect of suppressing the formation of a compound phase which adversely affects the magnetic properties in the heat treatment process. is there. Originally, Zr, Hf, Nb, etc. hardly form a solid solution with α-Fe, but by rapidly cooling the entire alloy to make it amorphous, Zr, Hf, Nb
b) to form a solid solution in a supersaturated state, and then heat-treat to adjust the solid solution amount of these elements to partially crystallize and precipitate as a fine crystal phase, thereby reducing the magnetostriction of the obtained alloy ribbon, and Magnetic properties can be improved. Also,
In order to precipitate a microcrystalline phase and to suppress the coarsening of the crystal grains of the microcrystalline phase, it is necessary to leave an amorphous phase which may hinder crystal grain growth at the grain boundaries. Further, the grain boundary amorphous phase is a Fe-M-based compound that deteriorates soft magnetic properties by dissolving M elements such as Zr, Hf, and Nb discharged from α-Fe by increasing the heat treatment temperature. Suppress generation. Therefore, Fe-Zr (Hf, Nb) -based alloy
Is important. X indicating the amount of B added is
If the content is less than 0.5 atomic%, the amorphous phase at the grain boundary becomes unstable, so that a sufficient effect of addition cannot be obtained. On the other hand, when X indicating the added amount of B exceeds 18 atomic%, the BM system and F
In the e-B system, the tendency of boride formation is increased. As a result, the heat treatment conditions for obtaining a fine crystal structure are restricted, and good soft magnetic properties cannot be obtained. Thus, by adding an appropriate amount of B, the average crystal grain size of the fine crystalline phase to be precipitated can be adjusted to 30 nm or less.

Further, in order to easily obtain the amorphous phase, it is preferable that one of Zr, Hf, and Nb, which has a particularly high amorphous forming ability, is contained, and a part of Zr, Hf, and Nb is other. , 4A to 6A group elements of Ti, V, Ta, Mo, W
Can be replaced with any of Such an M element is a diffusion species that is relatively slow, and the addition of the M element is considered to have an effect of reducing the growth rate of the fine crystal nuclei, and is effective for making the structure finer. However, when the value of y indicating the amount of the element M is less than 4 atomic%, the effect of reducing the nucleus growth rate is lost, and as a result, the crystal grain size becomes coarse and good soft magnetism cannot be obtained. In case of Fe-Hf-B alloy,
The average crystal grain size at Hf = 5 atom% is 13 nm, whereas it becomes coarse at 39 nm at Hf = 3 atom%. On the other hand, when y indicating the addition amount of the M element exceeds 9 atomic%, M-
The tendency to form a B-based or Fe-M-based compound is increased, and good properties cannot be obtained. In addition, the ribbon-shaped alloy after liquid quenching becomes brittle, and it becomes difficult to process the alloy into a predetermined magnetic core shape. Therefore, the range of y is preferably set to 4 to 9 atomic%.

Among these elements, Nb and Mo have a small absolute value of free energy of oxide formation, are thermally stable, and are hard to oxidize during production. Therefore, when these elements are added, the production conditions are easy, the production can be performed at low cost, and the production cost is also advantageous. Further, it is preferable that one or more of Si, Al, Ge, and Ga (X) be contained in an amount of 4 atomic% or less. These elements are known as metalloid elements, but these metalloid elements increase the ability to form an amorphous phase and solidify into a bcc phase (body-centered cubic phase) containing Fe as a main component. Melting changes the specific resistance and magnetostriction of the alloy. If the content of these elements exceeds 4 atomic%, it is not preferable because the magnetostriction increases, the saturation magnetic flux density decreases, or the magnetic permeability decreases.

Furthermore, one of Cu, Ag, Au, Pd, and Pt
The soft magnetic characteristics are improved by containing 4.5% by atom or less of one kind or two or more kinds (T). By adding a trace amount of an element that does not form a solid solution with Fe, such as Cu, the composition of the amorphous alloy immediately after quenching fluctuates, Cu forms a cluster in the initial stage of crystallization, and a relatively Fe-rich alloy is formed. Regions are formed, and the nucleation frequency of α-Fe can be increased.
Further, when the crystallization temperature was measured by differential thermal analysis, it seems that the addition of the above-mentioned elements such as Cu and Ag slightly lowers the crystallization temperature. It is considered that this is because the addition of these materials made the amorphous material non-uniform, resulting in a decrease in the stability of the amorphous material. 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. Therefore, the obtained composition is considered to have a fine grain structure. From the above viewpoints, similar effects can be expected for elements other than these elements that lower the crystallization temperature.

In addition to these elements, in order to improve corrosion resistance, it is also possible to add a platinum group element such as Cr, Ru, Rh and Ir. These elements are 5 atomic%
If the addition is larger than the above, the saturation magnetic flux density is significantly deteriorated. Therefore, the addition amount needs to be suppressed to 5 atomic% or less. In addition, if necessary, Y, La, Ce, Pr, Nd,
Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
m, Yb, Lu, Zn, Cd, In, Sn, Pb, A
s, Sb, Bi, Se, Te, Li, Be, Mg, C
The magnetostriction of the soft magnetic alloy obtained by adding elements such as a, Sr, and Ba can also be adjusted. In addition, in the soft magnetic alloy of the composition system, 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 is the same as that of the soft magnetic alloy used in the present invention. Of course, it can be considered.

When the above soft magnetic alloy is produced by adding these elements, specifically, an inert gas is partially supplied to the tip of the nozzle of the crucible used for quenching the molten metal. It can be manufactured in the atmosphere or in the atmosphere. Further, it is preferable that the alloy having the above composition is produced in a decompression chamber in which the atmosphere can be adjusted, and a ribbon-shaped soft magnetic alloy thin film can be easily obtained by spraying a molten metal in a crucible onto a quenching device such as a rotary drum to quench the molten metal. be able to. After quenching, the soft magnetic alloy ribbon has a structure mainly composed of amorphous. By heat-treating the ribbon, a large number of fine crystal grains can be precipitated. An alloy ribbon having characteristics can be obtained.

Next, the soft magnetic alloy ribbons are punched into a ring shape by pressing or the like to be laminated and stored in a cover such as a resin case, or the soft magnetic alloy ribbons are directly rolled to form a resin case or the like. It is possible to obtain a magnetic core with high magnetic permeability by housing it in the coating body or directly coating it with resin, but the thickness of the soft magnetic alloy ribbon used here can be freely selected within the range of 10 to 40 μm. You can This is because it is difficult to reduce the thickness of the soft magnetic alloy ribbon to a value less than 10 μm by the current manufacturing method of the quenching method, and if the thickness of the soft magnetic alloy exceeds 40 μm, it becomes fine in the amorphous phase. It becomes difficult to obtain a structure having crystal grains. Further, the size of the magnetic core thus obtained has an outer diameter of 10 mm or less and a height of 1.2 m.
AL value of 10 kHz at 0.1V input, even if m or less
In 4.0μH / N ² or more, 100kHz in 2.0μH / N ²
The above can be obtained, and the characteristics required as a magnetic core for a pulse transformer can be secured.

Further, in the case of the magnetic core using the alloy of the above composition system, the fluctuation of the AL value with respect to the room temperature can be ± 20% in the temperature range of -40 ° C to + 100 ° C. Since the absolute value of the magnetostriction of the band is 1 × 10 ⁻⁶ or less, there is little possibility that the characteristics will deteriorate due to the magnetostriction when the resin coating is applied or the resin case is sealed. Also, with the above configuration, the mounting area is 14.0 m.
It is possible to realize a pulse transformer of m × 14.0 mm or less and a height of 3 mm or less. Further, in the case of the above-mentioned composition system, a product having a magnetic permeability at 10 kHz of 40,000 or more can be easily obtained, so that an excellent pulse transformer can be obtained. Here, the AL value represents an inductance per number of turns of the winding, and when the cross-sectional area of the ring-shaped magnetic core is S and the magnetic path length is 1, the AL value = μ ₀ μ '(S /
1) (unit is H / N ² , μ ₀ is magnetic permeability of vacuum, and μ ′ is relative magnetic permeability of material). In addition,
If the inductance of the magnetic core is a stable and high value at 100 kHz or less, the pulse waveform can be transmitted as a regular rectangular wave whose shape is not lost. Further, in the case of a toroidal magnetic core formed by winding a soft magnetic alloy ribbon, the width of the ribbon that can be formed seems to be about 1.0 mm, so it is impossible to manufacture a thinner magnetic core. Although it seems that there is a core core structure that is formed by stacking rings punched from a soft magnetic alloy ribbon, it is possible to easily manufacture a core body thinner than 1.0 mm, and to reduce the thickness. .

[0020]

【Example】

Example 1 A soft magnetic alloy ribbon having a composition of Fe ₈₆ Nb _3.25 Zr _3.25 B _6.5 Cu ₁ and a plate thickness of 15 to 25 μm was used.
Then, a ring having an outer diameter of 7.8 mm and an inner diameter of 4.8 mm was prepared by punching and heat-treated at a temperature of 510 to 540 ° C. For the rings after heat treatment, calculate the required number of rings so that the height of the core part (ring thickness x number of sheets) is 0.3 to 0.95 mm, and the outer diameter is 9 mm, the inner diameter is 4 mm, and the height is 1. It was inserted into a case made of a PET type resin having an annular shape of 0.5 mm, and impedance and magnetic permeability were measured. The height inside the case is 1.0 mm.
FIG. 3 shows the case where the horizontal axis represents the filling rate (%) calculated from the height of the magnetic core (core) portion and the height inside the case when a soft magnetic alloy ribbon having a plate thickness of 15 μm is used with the above composition. Winding 2
It shows a change in impedance (| Z |) at 0 turns. Further, FIG. 4 shows a change in magnetic permeability (μ ′) when the filling rate (%) is plotted on the horizontal axis as in FIG. In the case where the rings are stacked and filled in the case, stress is likely to be applied in the thickness direction of the rings, and it is considered that the magnetostriction of the material and the stress cause a decrease in magnetic permeability. Fe ₈₆ Nb _3.25 Zr _3.25 used here
The magnetostriction constant of a soft magnetic alloy ribbon having a composition of B _6.5 Cu ₁ is 54
After heat treatment at 0 ° C. for 30 minutes, it was as small as −0.3 × 10 ⁻⁶ , so even if the filling rate was around 90% shown in FIG. 3 and FIG. 4, it was caused by packing in the case. The magnetic permeability did not decrease due to the applied stress, and the impedance increased as the filling rate increased. Therefore,
In order to obtain a high impedance value, it seems preferable to make the filling rate as high as possible.

Next, the plate thickness of the soft magnetic alloy ribbon used when the filling rate was set to 92 to 93% and A at the time of inputting 0.1 V
The measurement results of the L value (inductance per turn of the winding) are shown in Table 1 below.

[0022]

[Table 1]

FIG. 5 shows changes in the AL value at 10 kHz and 100 kHz when the plate thickness of the soft magnetic alloy ribbon is taken as the horizontal axis. It is generally known that, in a magnetic core using a soft magnetic alloy ribbon, the eddy current loss increases as the plate thickness of the soft magnetic alloy ribbon increases, the magnetic permeability at high frequencies decreases, and the inductance decreases. As shown in FIG. 5, even in the magnetic core using the soft magnetic alloy ribbon according to the present invention, as the plate thickness of the soft magnetic alloy ribbon used increases, 100 k
The AL value at Hz tended to decrease. On the other hand, the AL value at 10 kHz is equal to the plate thickness 2 of the soft magnetic alloy ribbon.
Almost the same value is obtained up to around 5 μm. Here, in the ISDN pulse transformer according to the above-mentioned standard, it is desirable that the AL value at 100 kHz is 2.0 μH / N ² or more, and from the above results, Fe ₈₆ Nb _3.25
Using a soft magnetic alloy ribbon having a composition of Zr _3.25 B _6.5 Cu ₁ , a toroidal magnetic core having an outer diameter of 7.8 mm, an inner diameter of 4.8 mm and a height of 0.92 to 0.93 mm is used. In this case, it was revealed that the required characteristics can be satisfied by setting the plate thickness of the soft magnetic alloy ribbon to 25 μm or less. The plate thickness of the soft magnetic alloy ribbon can be freely selected within the range of 10 to 25 μm, but if the manufacturing conditions of the soft magnetic alloy ribbon are simplified and the laminated thickness for the pulse transformer is taken into consideration, the thickness is 15 to 15 μm. It is more preferable to select the plate thickness in the range of 20 μm.

"Example 2" Fe₈₄Nb_3.5Zr_3.5B₈C
u₁Uses a soft magnetic alloy ribbon with a composition of 16 μm
From now on, a ring with an outer diameter of 7.8 mm and an inner diameter of 4.8 mm
Fabricated by punching and heat-treated at 520 ° C
Was. The magnetostriction constant of this alloy ribbon is about + 0.6 × 10.^-6so
there were. The height of the magnetic core of the ring after heat treatment
Calculate the required number of sheets so that is 0.5-0.9 mm,
Outer diameter 9 mm, inner diameter 4 mm, height 1.5 mm resin case
Impedance (| Z |) and permeability
(Μ ') was measured. Figure 6 shows the height of the magnetic core and the case.
When the horizontal axis is the filling rate (%) calculated from the height inside
Shows the change of impedance in 20 turns
Things. Also, in FIG. 7, the horizontal axis is the same as in FIG.
Shows the change in magnetic permeability in the case of. The figure
6 and FIG. 7 show the Fe obtained in Example 1 above.₈₆Nb_3.25
Zr_{3. twenty five}B_6.5Cu₁For soft magnetic alloy ribbon with the composition of
The results when there were were also shown.

The magnetic permeability of the magnetic core of this example is 60 due to the magnetostriction of the material and the stress caused by packing in the case.
When the filling rate was 75% or more, it began to decrease gradually, and when it was 75% or more, it rapidly decreased with an increase in the filling rate. Since the impedance is proportional to the magnetic permeability and the cross-sectional area of the magnetic core,
For both z and 100 kHz, the maximum was obtained when the filling rate was about 70%. For comparison, Fe ₇₃ in Figure 6 and Figure 7. ₅ S
i _13. shows the measurement results obtained by using the ₅ B ₉ Nb ₃ microcrystalline soft magnetic alloy ribbon of Cu ₁ a composition. This soft magnetic alloy ribbon has a plate thickness of 19.6 μm, a magnetostriction constant after annealing at 530 ° C. of + 1.3 × 10 ⁻⁶ , and a permeability μ ′ of 1 kHz.
Was 80,000. The soft magnetic alloy ribbon of this composition has a very brittle property, and when it becomes thinner, the magnetic permeability at a low frequency tends to decrease. For a sample with a thickness of 15 μm, the magnetic permeability μ ′ at 1 kHz is about A sample of this thickness was not used for the measurement because it was 50,000. It was found that in the alloy of this comparative example system, the impedance started to decrease from the lower filling rate. It is presumed that this is because magnetostriction begins to greatly affect the magnetic permeability as the packing density in the case is improved. On the other hand, when the magnetic core is manufactured using the soft magnetic alloy ribbon of the composition system according to the present invention, it is apparent that the filling rate at which the impedance starts to decrease is higher than that of the comparative example.

FIG. 8 shows the result of finding the relationship between the filling rate and the AL value for the same samples as those used in FIGS. 6 and 7. From the relationship shown in FIG. 8, when a ring obtained from a soft magnetic alloy ribbon is enclosed in a resin case to form a magnetic core, the filling rate is preferably 50% or more, more preferably 55 to 80%, and 10 kHz. It has become clear that it is more preferable to set it to 55 to 80% in order to satisfy the requirements at both of 100 and 100 kHz. "Example 3"

FIG. 9 shows the relationship between the temperature and the change in permeability in the magnetic cores having a filling rate of 80% used in the first and second embodiments.
Also, the relationship between the temperature and the change in magnetic permeability when ferrite is used as the magnetic core material is shown. From the results shown in FIG. 9, in the case of the transformer (Example 1: □, Example 2: ◯) manufactured by using the soft magnetic alloy according to the present invention and encapsulating in a resin case, -20 ° C to There is very little change in magnetic permeability in a wide temperature range up to + 100 ° C, ± 5% or so in the range of -20 ° C to + 70 ° C, and +5 to -10% in the range of -20 ° C to + 100 ° C. It is clear that there is a change in magnetic permeability due to temperature change, and it is clear that the change in magnetic permeability is less likely to occur than in the comparative example.

[0028]

As described above, according to the present invention, a magnetic core is formed by winding a soft magnetic alloy ribbon, or a ring obtained by punching the soft magnetic alloy ribbon by pressing is laminated to form a magnetic core. The main body is composed, the outer diameter of the magnetic core body is 10 mm or less, the thickness is 1.2 mm or less, and the AL value when inputting 0.1 V is 1
Since it is 4.0 μH / N ² or more at 0 kHz, it is possible to provide a magnetic core that can obtain a high inductance value with a small number of windings. Furthermore, the operating temperature is -20 to +100
Even if it fluctuates in the range of ° C, it is possible to reduce the fluctuation of the magnetic permeability as compared with the conventional structure having a ferrite magnetic core, and it is possible to obtain a stable inductance value. Also, the plate thickness 25
A pulse transformer magnetic core having the above-mentioned characteristics can be obtained by winding a soft magnetic alloy thin ribbon having a plate width of 1.2 mm or less and a width of μm or less. Next, when the magnetic core main body is configured by laminating rings obtained from the soft magnetic alloy ribbons, and the magnetic core main body is housed in the case at a filling rate of 50 to 80%, the decrease in magnetic permeability is reduced. Therefore, a high impedance value can be obtained, and a pulse transformer that meets the required characteristics can be provided.

The soft magnetic alloy constituting the magnetic core body is a soft magnetic alloy in which 50% or more of the structure is mainly composed of fine crystal grains having a body-centered cubic structure having an average crystal grain size of 30 nm or less. The soft magnetic alloy contains Fe as a main component, and T
In the case of containing B and one or more elements selected from the group consisting of i, Zr, Hf, V, Nb, Ta, Mo and W, the AL value at the time of inputting 0.1 V is 10 kHz. Is 4.0 μH / N ² or more, a high inductance value can be obtained with a small number of windings, and the operating temperature is −20 to +1.
Even if it fluctuates within the range of 00 ° C., it is possible to reliably obtain a pulse transformer magnetic core having less inductance fluctuation than that of the conventional structure having a ferrite magnetic core.

Further, as a soft magnetic alloy to be applied, Fe _b
B _x M _{y system, Fe b B x M y X} Z _{system, Fe b B x M y T} d based, or a _{Fe b B x M y T d} X Z based composition, each additional component elements 0.1V in the case of the specified ratio
The AL value at the time of input is 4.0 μH / N ² or more at 10 kHz, high inductance can be obtained with a small number of windings, and even if the operating temperature fluctuates within the range of -20 to + 100 ° C, the ferrite core is It is possible to reliably obtain a pulse transformer with less inductance variation than the conventional structure.

[Brief description of drawings]

FIG. 1 is an exploded view of a transformer including a magnetic core formed by stacking rings punched from a soft magnetic alloy ribbon according to the present invention.

FIG. 2 is an exploded view of a transformer including a magnetic core formed by winding a soft magnetic alloy ribbon according to the present invention.

FIG. 3 is a diagram showing a relationship between a filling rate and impedance when a case is filled with a soft magnetic alloy ring having a composition of Fe ₈₆ Nb _3.25 Zr _3.25 B _6.5 Cu ₁ .

FIG. 4 is a diagram showing a relationship between a filling factor and a magnetic permeability when a case is filled with a soft magnetic alloy ring having a composition of Fe ₈₆ Nb _3.25 Zr _3.25 B _6.5 Cu ₁ .

FIG. 5: 1 when the plate thickness of the soft magnetic alloy ring is taken as the horizontal axis
It is a figure which shows the change of AL value in 0 kHz and 100 kHz.

FIG. 6 shows a sample obtained by filling a case with a soft magnetic alloy ring having a composition of Fe ₈₆ Nb _3.25 Zr _3.25 B _6.5 Cu ₁ .
A sample obtained by filling a case with a soft magnetic alloy ring having a composition of Fe ₈₄ Nb _3.5 B ₈ Cu ₁ , and Fe _73.5 Si _13.5 B
It is a diagram showing the results of measuring the relationship between the respective filling rate and impedance of a sample obtained by filling a soft magnetic alloy ring case having a composition of ₉ Nb ₃ Cu _1.

7] For each sample having the same composition as the sample shown in FIG. 6,
It is a figure which shows the result of having measured the relationship between a filling factor and magnetic permeability.

8] For each sample having the same composition as the sample shown in FIG. 6,
It is a figure which shows the result of having measured the relationship of a filling factor and AL value.

9 is a diagram showing the results of measuring the relationship between temperature and the rate of change in magnetic permeability for each sample having the same composition as the sample shown in FIG. 6 and the ferrite material.

[Explanation of symbols]

 3 Magnetic core 5 Soft magnetic alloy ribbon 6 Magnetic core

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 391008456 Ken Masumoto 3-8-22 Uesugi, Aoba-ku, Sendai-shi, Miyagi (71) Applicant 396020800 Science and Technology Agency 4-8 Hommachi, Kawaguchi City, Saitama Prefecture (72) Inventor Yutaka Naito 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Katsuaki Hanya 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. ( 72) Inventor Takashi Hatauchi 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Akihiro Makino 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72 ) Inventor Shinjiro Wada 1163 Shimoice, Inari Town, Nagano City, Nagano Nagano Japan Radio Co., Ltd. (72) Inventor Yuichi Saito 1163 Shimoice, Inari Town, Nagano City, Nagano Prefecture Nagano Japan Radio Co., Ltd. (72) Inventor Akihisa Inoue Kawauchi Muzen, Aoba-ku, Sendai-shi, Miyagi 11-806 (72) Inventor Ken Masumoto 3-8-22, Uesugi, Aoba-ku, Sendai-shi, Miyagi

Claims (11)

[Claims] 1. An annular magnetic core body is constructed by laminating rings obtained from soft magnetic alloy ribbons having a plate thickness of 25 μm or less,
The outer diameter of this annular magnetic core body is 10 mm or less, and the thickness is 1.2.
A pulse transformer magnetic core having an AL value of 4.0 μH / N ² or more at a frequency of 0.1 V at a frequency of 0.1 mm at 10 kHz. 2. An E-type core, an I-type core and a U-type core are formed by laminating an E-type thin piece, an I-type thin piece and a U-shaped thin piece obtained from a soft magnetic alloy thin strip having a plate thickness of 25 μm or less, respectively. The E core and the I core, the E core and the E core, the U core and the I core, or the U core and the U core are combined to form a magnetic core body, and the magnetic core body has a thickness. AL value of less than 1.2mm and 0.1V input is 4.0 at 10kHz.
A pulse transformer magnetic core characterized by having a μH / N ² or more. 3. The pulse transformer magnetic core according to claim 1, wherein the ring is filled with 50% or more of the inside of a resin covering body. 4. The pulse transformer magnetic core according to claim 1, wherein the soft magnetic alloy ribbon has an absolute value of magnetostriction of 1 × 10 ⁻⁶ or less. 5. A ring-shaped magnetic core body is formed by winding a soft magnetic alloy ribbon having a plate width of 1.2 mm or less and a plate thickness of 25 μm or less, and the annular magnetic core body has an outer diameter of 10 mm or less and 0.1.
AL value at V input is 4.0 μH / N ^{2 at} 10 kHz
The pulse transformer magnetic core characterized by the above. 6. The pulse transformer magnetic core according to claim 1, wherein in the temperature range of −40 ° C. to + 100 ° C., the variation of AL value with respect to room temperature is within ± 20%. 7. A soft magnetic alloy comprising 50% or more of its structure mainly composed of fine crystal grains having a body-centered cubic structure having an average crystal grain size of 30 nm or less. Is mainly composed of Fe, Ti, Zr, Hf,
7. The pulse transformer according to claim 1, wherein the pulse transformer contains B and one or more elements selected from the group consisting of V, Nb, Ta, Mo and W. core. 8. The pulse transformer magnetic core according to claim 1, wherein the soft magnetic alloy constituting the magnetic core body has a composition represented by the following formula. Fe _b B _x M _y However, M is Ti, Zr, Hf, V, Nb, Ta, M
one or two or more elements selected from the group consisting of o and W, and b, x, and y indicating the composition ratio are: 75 ≦ b ≦ 93 at%, 0.5 ≦ x ≦ 18 at%, 4 ≦ y ≦
9 atomic%. 9. The pulse transformer magnetic core according to claim 1, wherein the soft magnetic alloy constituting the magnetic core body has a composition represented by the following formula. Fe _{b B x} M _{y X Z} where, M is, Ti, Zr, Hf, V , Nb, Ta, M
1 or 2 or more elements selected from the group consisting of o and W, X is 1 or 2 or more elements selected from Si, Al, Ge and Ga, and b, x and y and z are 75 ≦ b ≦ 93 atom%, 0.5 ≦ x ≦ 18 atom%, 4 ≦ y ≦
9 atomic% and z are 4 atomic% or less. 10. The pulse transformer magnetic core according to claim 1, wherein the soft magnetic alloy constituting the magnetic core body has a composition represented by the following formula. Fe _{b B x} M _y T _d where, M is, Ti, Zr, Hf, V , Nb, Ta, M
1 or 2 or more elements selected from the group consisting of o and W, and T is 1 or 2 or more elements selected from the group consisting of Cu, Ag, Au, Pd, and Pt. , B, x, y and d showing composition ratios are 75 ≦ b ≦ 93 atom%, 0.5 ≦ x ≦ 18 atom%, 4 ≦ y ≦
9 atomic% and d is 4.5 atomic% or less. 11. The pulse transformer magnetic core according to claim 1, wherein the soft magnetic alloy constituting the magnetic core body has a composition represented by the following formula. _{Fe b B x M y T d} X Z where, M is, Ti, Zr, Hf, V , Nb, Ta, M
O is one or more elements selected from the group consisting of W, and T is one or more elements selected from the group consisting of Cu, Ag, Au, Pd, and Pt. , X
Is one or more of Si, Al, Ge, and Ga, and b, x, y, d, and z indicating the composition ratio are 75 ≦ b ≦ 93.
Atomic%, 0.5 ≦ x ≦ 18 atomic%, 4 ≦ y ≦ 9 atomic%, d is 4.5 atomic% or less, and z is 4 atomic% or less.