DE3414056A1 - AMORPHER WRAPPED CORE - Google Patents

Description

34H056

description

The invention relates to an amorphous wound core with a gap which is used for filtering out symmetrical Interference voltages ("normal mode noise") and is suitable for smoothing the output.

Due to the recent development of electronic devices, switching power supplies are becoming more and more used more. Accordingly, chokes for smoothing the output and filters for symmetrical interference voltages are in widely used.

Magnetic reactor cores usually consist of sintered ferrites, silicon steel strips, dust cores Permalloy (mass cores), etc. Recently, the use of amorphous magnetic cores for chokes has been proposed. Dust cores do not pose a noise problem because they do not have a gap ·. and they have relatively good frequency characteristics. On the other hand, they have a low permeability, so that they are not necessarily due to their low impedance are satisfactory when used for chokes. Ferrite cores have a low saturation magnetic flux density Bs of about 5,000 G, (0.5 T) so that gaps are necessary to provide a sufficient saturation magnetic field. However, this lowers the effective permeability of the cores, which leads to chokes with poor magnetic properties. Furthermore, in terms of frequency characteristics, the ferrite cores are inferior to the dust cores. Have silicon steels the disadvantage of large core losses ("iron losses"). Amorphous cores have higher saturation magnetic flux densities Bs than ferrite cores. Amorphous cores are advantageous over silicon steel cores in terms of core losses, although they are one have lower saturation magnetic flux density Bs than the latter.

Japanese Patent Laid-Open Nos. 57-82454 and 57-83005 disclose wound cores made of an amorphous Fe-Ni-Si-B alloy and an amorphous Fe-Co-Si-B-Si-B alloy or from an amorphous Fe-Co-Si-B alloy.

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These amorphous wound cores have no gap, however, so that their permeabilities rapidly increase as the magnetic field increases fall off. This tendency is unfavorable when used for filters to remove symmetrical interference voltages (Normal mode noise filter) and for output smoothing devices.

It is an object of the present invention to provide an amorphous, wound core that is used in filters for symmetrical Interference voltages (normal mode noise) and output smoothing devices can be used, good direct current superimposition properties and has good impedance freedom.

It is also an object of the present invention to provide an amorphous wound core which is precise in of the gap is excellent.

This object is achieved with an amorphous wound core specified in the preamble of claim 1, according to the invention according to the characterizing part of this, Claim is designed.

Further, advantageous refinements of the invention emerge from the subclaims.

The amorphous wound core according to the present invention has at least one gap

The amorphous wound core is impregnated with a resin so that after it is provided with a gap retains its shape and dimensions. The gap can be filled with a non-magnetic spacer be. The resin-impregnated wound core may be further coated with a non-conductive resin around it from. to insulate a conductor wire wound on the core. Figure 1 shows a perspective view of a

amorphous wound core according to an embodiment of the present invention;

FIG. 2 is a diagram showing the relationship between the cutting speed with a cutter

tool and the change in thickness of the amorphous

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wound core after it has been provided with a gap;
FIG. 3 shows in a diagram the relationships between the cutting speed with a cutting tool and the gap width of the amorphous wound

Kernes;

FIG. 4 shows in a diagram the relationships between . the layer thickness and the inductance of the with one

Split amorphous wound core; FIG. 5 shows in a diagram the complex permeabilities of the magnetic cores as a function of the frequency;
FIG. 6 shows in a diagram the absolute values of the complex permeabilities of the magnetic cores as a function of the frequency;

Figure 7 shows: '. Dnv. A digram the absolute values of the complex Impedance of reactors as a function of frequency ';

FIG. 8 shows in a diagram the relationships between a direct current bias field which is generated with an alternating current magnetic field is combined, and the incremental (differential) permeabilities of magnetic cores;

FIG. 9 shows in a diagram the frequency dependence of the core losses (“iron losses ¹¹ ) of magnetic cores.

Figure 1 shows an amorphous wound core 1, which consists of an amorphous alloy strip 2 and has a gap 3.

Any amorphous alloy with a high saturation magnetic flux density Bs can be used in the present invention. Amorphous iron-based alloys are particularly desirable because they exhibit a high saturation magnetic flux density Bs. Amorphous iron-based alloys, which can be used in the present invention include those alloys identified by the general

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Formula: Fe ^ Ni ^ T Si B, where T one or more elements from the group denotes Be, Mg, Ca, Sr, Ba, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, Includes W, Mn, Ru, Co, Pd, Cu, Zn, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy; furthermore, d + e + f + g + h = 100; 72 ^ d + e £ 85; 0.05 £ e / (d + e) <0.40 CKf <_3; 7 <g <16; 7 <h <10; 155 g + h £ 25.

Individual examples of these amorphous iron-based alloys are:
Fe ₇₀ Ni ₈ Si ₁₃ B ₉ , Fe ₆₃ Ni ₁₅ Si ₁₃ B ₉ , Fe ₅₄ Ni ₂₄ Si ₁₃ B ₉ , Fe ₇₈ Ni ₅ Si ₈ B ₉ , Fe ₇₀ Ni ₈ Ti ₃ Si ₁₁ B ₈ , Fe ₆₈ Ni ₇ Cr ₂ Sr ₁ Si ₁₄ B ₈ , etc., see Japanese Patent Laid-Open No. 57-82454.

Another example of a useful amorphous Fe-based alloy is represented by the general formula Fe-, Co T-Si B, where T represents one or more elements of the group comprising Be, Mg, Ca, Sr, Ba, Ti, Cr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Ru, Ni, Pd, Cu, Zn, Y, Ce. , Pr, Nd, Sm, Eu, Gd, Tb, Dy, where d + e + f + g + h = 100 and 72 <d + e <8 5; 0.05 <e / (d + ek 0.70, 0 ^ f <3; 7 ^ g </ l6; 7 <h </ lO; 15_ <g + h £ 25. Individual examples are Fe ₇₈ Co ₅ Si ₈ B ₉ , Fe ₇₀ Co ₈ Si ₁₃ B ₉ , Fe ₆₃ CO ₁₅ Si ₁₃ B ₉ , Fe ₅₄ Co ₂₄ Si ₁₃ B ₉ , Fe ₃₉ Co ₃₉ -Si ₁₃ B ₉ , etc., see Japanese Patent Laid-Open No. 57 These Fe-based alloys provide wound magnetic cores with excellent DC voltage superposition properties due to their high saturation magnetic flux density. Amorphous alloys are used in the form of a ribbon 2. The ribbon 2 is wound until the core thickness reaches the desired level. The amorphous alloy ribbon 2 can be used with any of the known methods can be prepared.

The amorphous wound core 1 may be subjected to a heat treatment to improve its magnetic properties. The heat treatment is annealing of the wound core at temperatures of 250 ⁰ C to 450 ° C and subsequent cooling with a rate of

run less than 300 ° C / hour. If necessary, a magnetic field can be applied during the heat treatment. The wound magnetic core 1 is provided with a gap 3. In the exemplary embodiment shown in FIG. 1, the gap 3 extends over a vertical cross section of the wound core 1. The gap 3 can
in general, however, be of any shape and size.
It can have a uniform width or it can be tapered. The gap 3 can by a grinding process with a

Grinder are made. The width of the resulting sap does not necessarily have to be equal to the thickness of the
used grinder, but may be due to slight deformation of the wound core after cutting
be smaller than the latter. The gap width can vary according to the cutting speed. The radial thickness

of the wound core can also depend on the speed of the cutting process with which the core is involved
a gap.

The gap 3 can be filled with a non-magnetic spacer to ensure the stability of its dimensions to ensure. The non-magnetic spacer can be made of plastic, aluminum, etc.

The amorphous wound core is solidified with resins so that it maintains its desired dimensions and shape after it has been provided with a gap. The solidification of the wound core with resins can be carried out by impregnating it with liquid resins
that liquid monomeric or oligomeric, polymeric solutions with organic solvents, melted resins, etc.

wherein the resins used can include thermoplastic resins and thermosetting resins. If curable Resins are used, they preferably contain curing agents. To solidify the wound core preferably epoxy resin with a suitable curing agent

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- Q -

and an inorganic varnish or varnish is used.

When a liquid epoxy resin containing a curing agent is used, the wound core is first immersed in the liquid resin, placed in a vacuum chamber to cause the resin to penetrate the innermost part of the core, removing air bubbles therefrom , and is then heated to temperatures of about 85 ⁰ C bsi about 100 ⁰ C to cure the epoxy resin. Inorganic paints can also be used because they easily penetrate the wound core. The wound core is immersed in an inorganic lacquer and then heated ^{to temperatures of approximately 100 °} C. to 150 ^° C., preferably 120 ^{° C.}

The solidification of the wound core 1 with resins can also be carried out by making the surface of a amorphous tape 2 is coated with resins, the tape 2 is then wound to form a core, and then the wound core 1 is heated. Resins for coating can also be thermoplastic or thermosetting resins be! The amorphous wound core can still be non-conductive Resins are coated. The surface coating of the core should be so thick that an insulation of the Core is ensured by wires wound on it. Regarding the space factor, however, the surface coating should have a reduced thickness. Therefore, the insulating resin coating should generally have a thickness between about 0.5 mm to about 2 mm.

In a preferred embodiment, the amorphous wound core 1 is made by using a tape 2 from an amorphous alloy., to ^ a toroidal shape is wound, the resulting> -toroidal wound The core is subjected to a suitable heat treatment, is impregnated with resin and is provided with a gap 3; then a non-magnetic spacer is inserted into the gap 3, and the core surface is with a or more insulating resins coated. A metal sleeve can serve as a spacer.

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The present invention will now be described and explained in greater detail on the basis of individual exemplary embodiments.

example 1

A molten alloy of FeBa ₁ Ni ₇ 5Si _1fi Bg was ejected from a thin nozzle onto a copper roller rotating at high speed to form a thin amorphous ribbon about 20 µm thick and 6.5 mm wide. The amorphous ribbon was wound to form a toroidal core having an outer diameter of 20 mm, an inner diameter of 12 mm and a height of 6.5 mm. The toroidal core was immersed in a curing agent-containing solution of an epoxy resin sold under the name "EPIKOTE", placed in a vacuum chamber to remove air bubbles and then cured with heat. The wound core impregnated with epoxy resin was cut with a grinder to form a gap, so that a wound core shown in FIG. 1 was obtained.

Example 2

For the wound core 1 produced according to Example 1, measurements were carried out to determine how the thickness of the wound core changes when it is used to form a gap 3 with the aid of a grinder 0.3 mm thick is cut at different cutting speeds.

To continue the effects of the resin impregnation on the To determine the change in thickness of the wound core, the same measurements were made for one impregnated with EPIKOTE wound core like a non-impregnated core. The results are shown in FIG. Figure 2 shows that at a cutting speed

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Up to about 10 mm / min., there is essentially no change in the thickness of the wound core impregnated with the resin exits. On the other hand, a non-impregnated core experiences a large change in thickness at every cutting speed.

Example 3

For a wound core produced according to Example 1, measurements of the width of the gap were made. 3, the one with a 0.3. mm thick grinder made at different cutting speeds was executed. The results are shown in FIG. As shown, the gap 3 is slightly narrower than the thickness of the grinder or Cutting tool, and the gap width gradually increases with increasing cutting speed.

Example 4

The amorphous wound core made according to Example 1 and saturated at 100 Oe became one. Surface coating with an insulating resin (EPIKOTE), and on it was a lead wire with 10 turns wound up. The inductance of the wound core was measured at different thicknesses of the surface coating. The results are shown in FIG. The inductance gradually increases as the coating becomes thicker. In order to achieve a good space factor, i.e. a high inductance, the coating should be smaller than about 2 mm. It should be noted that an amorphous wound core 1 with a surface coating of less than 2 mm has a higher inductance than a dust core without a gap and than a ferrite core with a gap.

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- 12 Example 5

An amorphous wound core 1 produced according to Example 1 with a gap of 0.335 mm in width was measured with regard to its complex permeability at various frequencies. The real part μ ¹ and the imaginary part μ "of the complex permeability are shown in FIG. 5 in comparison with those of a dust core made of Mo permalloy. It can be seen that the amorphous wound core according to the present invention has a higher imaginary part μ" possesses complete permeability, which means that it works particularly well with normal-mode noise filters. FIG. 6 shows the absolute value of the complex permeability IyI for the above amorphous wound core in comparison with that of a dust core made of Mo permalloy. It is found that the resin-impregnated amorphous wound core with a gap of 0.335 mm in width has a substantially constant | μ | over a wide frequency range shows which is considerably higher than the value of | μ | of the dust core is made of Mo-Permalloy. This means that the permeability of the amorphous wound core of the present invention has very good frequency properties.

Example 6

Five turns of a wire of 0.25 mm in diameter were wound on the aforementioned amorphous wound core to form a reactor, and the resulting reactor was measured for impedance. FIG. 7 shows the absolute value of the complex impedance \ zj | ... of this amorphous wound core over a wide frequency range in comparison with that of a dust core made of Mo-Perammloy. It can be seen that the amorphous wound core has a higher | z | over the entire measured frequency range has as a dust core made of Mo permalloy.

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- 13 Example 7

The effect of the gap width on the direct current superposition characteristic is now shown shown. The following five amorphous wound cores with different gap widths were made from Mo permalloy together with a dust core in terms of incremental (differential) permeability μΔ measured.

Amorphous wound core + gap width (mm)

B 0.335

C 0.421

D 0.516

E 0.721

⁺ ) The amorphous wound cores

were all prepared in the manner described in Example 1 -1-.

The incremental permeability μΔ is defined by the following equation:

where ΔΒ and ΔΗ are the incremental magnetic flux density, respectively and denote the incremental magnetic field in the case where an alternating current magnetic field is equal to a direct current field of is superimposed at a certain level.

The measurements were made with a DC bias field in the range from 0 to 100 Oe (0 to 7957.7 A / m) and its own alternating current magnetic field with a frequency of IkHz executed. The results are shown in FIG.

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It can be seen that the amorphous wound core provided with a gap has an incremental permeability μΔ which is higher than that of a dust core made of Mo permalloy and which does not decrease rapidly as the direct current magnetic field H _ increases. An amorphous wound core with no gap has a very high incremental permeability μΔ at a low DC magnetic field H _nf , (less than 10 Oe or less than 795.7 A / m), but the value of μΔ drops rapidly when the value of H _n -, increases. These circumstances indicate that a gapped amorphous wound core according to the present invention exhibits good DC superimposition properties which are necessary for normal mode noise filters, chokes and output smoothers.

I!

Example 8

The amorphous wound core B according to the present invention as well as for! a dust core made of Mo permalloy core loss ("iron loss") was measured. The results are shown in FIG. You can see that one with one Gap-provided amorphous wound core according to the present invention Invention in terms of core losses better

Frequency characteristics

possesses than the dust core. As before

mentioned, the amorphous one provided with the gap has wound Core according to the present invention has good direct current superimposition properties and a high complex permeability.

It is therefore particularly suitable for normal mode noise filters and for

Suitable for starting smoothing.

The present invention is preferred by way of

Embodiments have been described, but it is not limited to these and can be in various ways

be modified. <

RS / JG!

Claims (15)

PATENT CLAIMS hj. Core made of magnetic material for use in chokes, Filters or the like, characterized in that it consists of amorphous, wound material and has at least one gap. 2. Core according to claim 1, characterized in that that it is impregnated with a resin. 3. Core according to claim 1 or 2, characterized in that the gap with a non-magnetic Spacer is filled. 4. Core according to one of claims 1 to 3, characterized g e k e η η draws that it is made of an iron-based alloy. 5. Core according to one of claims 1 to 4, characterized in that the synthetic resin impregnated core is coated with an insulating resin. 6. Core according to one of claims 1 to 5, characterized in that the insulating Coating of the resin-impregnated core has a thickness of less than 2 mm. 7. Core according to one of claims 1 to 6, characterized in that the gap with a thin metal sleeve is covered. 8. A method for producing a core according to any one of claims 1 to 7, ge. denotes by the following process steps: Winding an amorphous alloy ribbon to form a toroidal core; Impregnating the wound core with resin to solidify it; Making a gap on the resin impregnated wound core. 9. The method according to claim 8, characterized in that g * _e kenn z_ eich net that after the on / icke in of the band from amorphous Alloy a heat treatment is carried out. 10. The method according to any one of claims 8 or 9, characterized in that according to the Attaching the gap a non-magnetic spacer is inserted into the gap. 11. The method according to any one of claims 8 to 10, characterized in that the surface of the core is coated with insulating resin. 12. The method according to e inem of claims 9 to 11, characterized in that the heat treatment is a tempering of the wound core at temperatures of 250 ⁰ C to about 450 ⁰ C and a cooling at a rate of less than about 300 ° C / Hour includes. 13. The method according to any one of claims 9 to 12, thereby gc.e indicates that the annealing is carried out in a direct current or alternating current magnetic field will. 14. Normal mode noise filter, characterized in that it is a resin-impregnated, amorphous having wound core which is provided with a gap. 15. Ausgangsglättvorrichtung, characterized g e 'net characterizing in that it comprises a resin-impregnated, amorphous wound core, the mit.einem gap is provided.