JPH0469401B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Technical Field The present invention relates to an amorphous alloy ribbon-wound magnetic core and a method for manufacturing the same. More specifically, the present invention relates to a magnetic core used in a high-power magnetic switch used in a particle accelerator or the like, and which has a short switching time. In particle accelerators, the magnetic core is required to generate high-power pulses of more than 1 GW at high frequencies of more than 10 KHz and short switching times. Conventionally, high-pressure gas switches such as thyratrons have been used as pulse generators for particle accelerators, but their output and switching time are unsatisfactory. On the other hand, capacitors C ₁ , C ₂ . . . , C _o and saturable inductors L ₁ , L ₂ as shown in FIG.
..., L _o , the capacitance of each capacitor is equal, and the inductance of each inductor is configured to be smaller as the stage increases, and a DC power is applied to the input side to charge the capacitor _C1 , After charging, the inductor L ₁ reaches saturation, its impedance decreases, and the charge flows to the capacitor C _2. By sequentially performing this charging and saturation up to n stages, the energy of the original waveform is maintained. However, a magnetic switch is known that sequentially compresses the pulse width to obtain a short pulse width and high output pulse. A magnetic core is used for each stage of inductors L ₁ , L _{2 .} . . , _Lo in such a magnetic switch, and the magnetic core is required to have the following characteristics. First, since saturability must be good, it is necessary to have good squareness and small magnetic permeability μsat in the saturation region. According to Br/B ₁₀ (Br
is the residual magnetic flux density, B ₁₀ is the magnetic flux density at 100e, the second
(see figure) is preferably 0.7 or more. Also,
Since μsat is proportional to the required core volume, μsat
The smaller the value, the more compact the magnetic core can be. The theoretical maximum compression factor for pulse width is (μunsat/μsat)1/
2 (μunsat is the magnetic permeability in an unsaturated region), the larger the difference between μunsat and μsat, the fewer stages the LC circuit uses and the smaller the magnetic switch becomes. Second, the inductor is B
Since the magnet is excited from -Br on the -H curve to Bs (Bs is the saturation magnetic flux density), △Bs=|-Br|+Bs must be large. Thirdly, since the magnetic core is excited with a current of about 10 KHz or higher, energy loss under high frequencies must be small. Fourthly, it is necessary that the characteristics change little over time. Next, problems associated with the fact that the magnetic core for a magnetic switch is a wound core will be explained. Generally, in a wound core for a magnetic switch, when a high frequency current is applied to the magnetic core, the magnetic flux density changes instantaneously, and a large voltage proportional to the extent of this change is generated, so there is a risk of short circuiting between the wound layers. In order to prevent such short circuits, it is necessary to insulate the winding layers. Therefore, when implementing the method of insulating the winding layers, the first to fourth required characteristics must not deteriorate. (a) Prior art Ferrite is commonly used as a magnetic core material for magnetic switches.
Since the third magnetic property is insufficient, there is a drawback that the magnetic core becomes large. On the other hand, ribbons of amorphous magnetic alloys have also been put into practical use as magnetic core materials. In the case of silicon steel sheets, which are generally used as magnetic core materials, a glassy film is formed on the surface by high-temperature annealing, and an insulating film is applied and baked. However, since the temperature required to perform such interlayer insulation treatment is high, this technique cannot be applied to interlayer insulation of amorphous alloys. Therefore, in order to perform interlayer insulation of the amorphous alloy ribbon, it is necessary to apply an insulating material such as MgO or
A layer of insulating material such as polyimide or polyethylene terephthalate must be interposed between the amorphous alloy ribbons. In the former method of applying an insulating material such as MgO, it is difficult to apply the insulating material well because both ends of the amorphous alloy ribbon are generally sharp, which can lead to interlayer short circuits. It is not practical because it is easy to do. Next, as a characteristic of amorphous alloys, in order to obtain good magnetic properties, the temperature must be below the crystallization temperature and about 300%
It is necessary to heat treat the amorphous alloy between ~500°C. Note that polyimide and the like do not have sufficient heat resistance at the above heat treatment temperature, so heat treatment cannot be performed with a polyimide film or the like interposed between the amorphous alloy ribbons. Therefore, the amorphous alloy ribbons are heat treated and then a layer of insulating material is interposed between the ribbons. The present inventor has discovered the magnetic properties of an amorphous alloy ribbon-wound core,
In particular, in order to improve △Bs = |-Br|+Bs, the amorphous alloy ribbon must be heat-treated in a wound state, and the state of interposition of the insulating material layer must be specified. I found out. (c) Object of the invention The object of the invention is to provide an amorphous alloy-wound core with good magnetic properties and a method for manufacturing the same. (D) Structure of the Invention The amorphous alloy wound magnetic core according to the present invention is an amorphous alloy ribbon magnetic core, and the amorphous alloy ribbon is wound in the winding direction in a heat-treated state. , and is characterized in that an insulating film is inserted between the wound layers of the amorphous alloy ribbon to insulate the wound layers. The manufacturing method according to the present invention is a method for manufacturing an amorphous alloy ribbon-wound magnetic core, in which the first end of the amorphous alloy ribbon is wound on the inside and the second end is on the outside. Next, the first wound body is heat-treated, and then an insulating film is placed on the amorphous alloy thin body, and the first end is located on the inside and the second end is located on the outside. The amorphous alloy ribbon and the insulating film are wound around a second winding body, and the inner diameter of the second winding body is substantially the same as the inner diameter of the first winding body. . Hereinafter, the constituent elements of the present invention will be explained. According to experiments conducted by the present inventor, when an amorphous alloy thin ribbon is heat-treated at a temperature below the crystallization temperature in the production of an amorphous alloy thin ribbon wound magnetic core (hereinafter simply referred to as a magnetic core), It has been found that when the ribbon is heat-treated in an expanded state, the magnetic properties deteriorate due to the winding of the heat-treated ribbon to produce a magnetic core. Therefore, the above heat treatment needs to be performed on the wound amorphous alloy ribbon (first wound body). FIG. 3 shows the amorphous alloy wound body 1 (first wound body) in a heat-treated state, its inner diameter d ₁ , outer diameter D ₁ ,
and an inner first end 1b and an outer second end 1a. Heat treatment temperature is usually about 300 to about 500℃, about 30 to
The temperature and conditions are selected to obtain the best magnetic properties, especially ΔBs, within the above range, depending on the composition of the amorphous alloy. Such treatment is usually carried out by heating at a temperature below the Curie point for an appropriate time in a magnetic field of, for example, 5 Oe or more, particularly 10 Oe or more, and then cooling, for example air cooling. After heat treatment in a magnetic field, anisotropy is imparted in the longitudinal direction within the ribbon surface. In addition,
The atmosphere for such heat treatment is air, vacuum,
It may be in an inert gas, a non-oxidizing gas, or the like. The amorphous alloy wound body 1 is formed by winding a long thin plate having a thickness of 20 μm or less and a width of about 10 to 500 mm, particularly about 12.7 to 127 mm. In this case, if the thickness exceeds 20 μm, energy loss at high frequencies will increase and the amount of heat generated will increase.
The thickness is particularly 5 to 18 μm, more preferably 8 to 18 μm.
It is 15 μm. As described above, in manufacturing a magnetic core, it is necessary to perform interlayer insulation, but heat treatment cannot be performed with an insulating film interposed between layers. FIG. 4 shows a magnetic core 10 (second wound body) with an insulating film 2 interposed between the phases of the amorphous alloy ribbon after heat treatment. magnetic core 1
0 is generally larger than the outer diameter D ₂ of the amorphous alloy wound body 1 (D ₂ >D ₁ ) because the insulating film ₂ is interposed between the layers. Magnetic core according to the present invention (second
In the amorphous alloy wound body 1 (wound body), the first end 1b and the second end 1a are located on the inside and outside, respectively, as in the heat treatment, and the inner diameter d ₂ of the magnetic core 10 is It is necessary that the inner diameter (d 1 ≈d ₂ ) is approximately equal to the inner diameter d ₁ of the one-wound body (d ₁ ≒d 2 ). Above inner diameter d ₂ and d ₁
If the relationship is d ₂ ≫ d ₁ or d ₂ ≪ d ₁ and/or the first end 1b (second end 1a) is located outside (inside), ΔBs is significantly lower than in the magnetic core of the present invention. Become. Preferably, Δd=|d ₂ −d ₁ /d ₁ |×100 (%) is 0 to about +40%, −20%. △d=0%
In the case of , △Bs is the highest. Hereinafter, winding the amorphous alloy ribbon in the same direction and in the opposite direction to the heat-treated winding direction will be referred to as forward winding and reverse winding, respectively. Forward winding is an essential component of the magnetic core of the present invention. On the other hand, between the heat treatment process and the process of inserting the magnetic core insulating film between the layers, even if the process of winding in the opposite direction or flattening the amorphous alloy ribbon is performed, the magnetic core will not move in the forward direction. As long as it is wound, the magnetic properties of the amorphous alloy ribbon of the magnetic core will not deteriorate due to reverse winding or flat rolling. Therefore, the magnetic properties of the amorphous alloy ribbon are not affected by the winding (rolling) history between the heat treatment and the final winding process, while the ribbon can be wound in the forward direction with good magnetic properties. It has a kind of shape memory effect. Next, a specific example of manufacturing the second wound body by the method of the present invention will be described with reference to FIG. In FIG. 5, 20 is an amorphous alloy ribbon obtained by winding the heat-treated wound band (first wound body) 1 (FIG. 3) in the opposite direction, and 21 is an insulating film. It is unwoundly wound around the frames 22 and 23. 24 is an amorphous alloy ribbon 20, preferably
A magnetic core is shown in which insulating films 21 having a thickness of 0.1 to 25 μm are wound in alternating layers. In addition, magnetic core 2
When winding up, it is necessary to apply appropriate tension to the amorphous alloy ribbon 20 and the insulating film 21. Appropriate tension strength is generally from several grams to several tens of grams. Furthermore, since there is a gap between the ends of the amorphous alloy ribbon 20 that is only about the size of the insulating film 21, there is a possibility that discharge may occur.
The width of the ribbon 1 must be larger than the width of the ribbon 20. The calculated wide width of the insulating film (on one side) is approximately several tens of μm, taking into consideration atmospheric discharge, induced voltage, magnetic core usage conditions (magnetic switch drive conditions), size of amorphous alloy ribbon, magnetic core size, etc. This is good, but in actual winding work, runout inevitably occurs, so the wide insulating film (on one side) is 2 mm.
In view of the above, it is preferable to set the thickness to 3 to 5 mm. In this case, an insulating material may be coated or adhered to the amorphous alloy ribbon after heat treatment, but the insulating performance will be inferior to that shown in FIG. 5. The end (second end) of the amorphous alloy ribbon 20 and the end of the insulating film 21 are attached to the outermost part of the magnetic core 24 with an adhesive,
It is fixed by welding, tape, etc., or by caulking with caulking claws provided on the winding frame, etc. (e) Example An amorphous alloy ribbon with a thickness of 15 μm and a width of 25.4 mm, with a composition of (F _e0.949 M _o0.051 ) ₇₈ (S _i0.591 B _0.273

C _0.091 P _0.045 ) ₂₂ with outer diameter (D ₁ - Figure 3) 127
mm, the first wound body wound to an inner diameter (d ₁ ) of 76 mm is 400 mm.
When heat treated in a magnetic field of 300e for 2 hours at ℃,
The obtained △Bs was 2.7 Tesla. Next, the first wound body was wound in the opposite direction with the inner diameter (d ₁ ), and ΔBs=1.9 Tesla was obtained. In this case, a 2 μm thick polyethylene terephthalate film was inserted between the amorphous alloy ribbon layers. Next, a second winding body is formed by winding the first winding body in the forward direction.
I made a rolled body. In this case, a polyethylene terephthalate film with a thickness of 2 μm is inserted between the layers of the amorphous alloy ribbon, and the inner diameter (d ₂ ) and outer diameter (D ₂ ) of the second wound body are changed as shown in the following table. Ta. Each △
Bs is shown in the table.

[Table] From Table 1, it can be seen that a high ΔBs can be obtained when Δd is not equally large. (F) Effects of the Invention According to the present invention, a magnetic core with a high ΔBs can be manufactured in manufacturing a magnetic core that involves heat treatment and winding.

[Brief explanation of the drawing]

Figure 1 is the equivalent circuit of the magnetic switch, Figure 2 is the BH curve of the magnetic core, Figure 3 is a conceptual diagram of the first winding body, Figure 4 is a conceptual diagram of the second winding body, and Figure 5 is the conceptual diagram of the second winding body. It is a conceptual diagram of the method of winding a two-wound body. 1... Amorphous alloy wound body (first wound body), 1a
...Second end, 1b...First end, 2...Insulating film, 10...Magnetic core, 20...Amorphous alloy ribbon, 2
1...Insulating film, 24...Magnetic core (second winding body), 2
6...Tension adjustment roll.

Claims (1)

[Scope of Claims] 1. An amorphous alloy ribbon-wound magnetic core, wherein the amorphous alloy ribbon is wound in the winding direction of a heat-treated state, and the amorphous alloy ribbon is wound in a winding direction in a heat-treated state. An amorphous alloy ribbon-wound magnetic core characterized in that an insulating film for insulating between the wound layers is interposed between the wound layers. 2. In the method for manufacturing an amorphous alloy ribbon-wound core,
creating a first wound body by winding the amorphous alloy ribbon so that the first end is on the inside and the second end is on the outside;
Next, the first wound body is heat-treated, and then an insulating film is disposed on the amorphous alloy thin body, and a second wound body is heated, and the first end is located inside and the second end is located outside.
An amorphous material characterized in that the amorphous alloy ribbon and the insulating film are wound around a wound body, and the inner diameter of the second wound body is substantially the same as the inner diameter of the first wound body. Method for producing alloy thin ribbon magnetic core.