JPS6140015A - Manufacture of core - Google Patents

Abstract

PURPOSE:To obtain the core having excellent quality by a method wherein the outside surface of the core made of an amorphous magnetic alloy thin plate is coated by a heat-reflecting material, a heat-insulating material is covered thereon, the core is excited, and then it is annealed by iron loss. CONSTITUTION:Heat reflecting copper materials 13 and 14 are coated on the surface of the wound core 11 of an amorphous magnetic alloy thin, plate the above-mentioned materials are enclosed by ceramic fibers 15 and 16, a coil 18 is wound around the center leg, and coils 19 and 19 are temporarily wound around the outer leg in the reverse direction each other. The voltage of a high frequency AC power source 21 is adjusted 28, a current is applied to the coil 19, the coil is heated up to 400 deg.C by the internal heat generated on the core 11, and this condition is maintained for 30-120min. As the coils 19 and 19 are wound reversely each other, no voltage is induced on the coil 18. The AC power source is changed to a DC power source, a magnetic field is formed on the wound core 11, and the core is cooled in the magnetic field. After an annealing is performed thereon, the coil 19 is removed. According to this constitution, the core can be annealed at a uniform temperature, the deterioration in magnetic characteristics of the thin plates can be prevented, the radiant heat generating from the core can be suppressed by the heat reflecting material, the convectional heat radiation can be suppressed by the heat insulating materials 15 and 16, the generated heat is stored in the core, and an annealing can be performed quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of manufacturing an iron core for use in transformers, etc., in which an iron core made of an amorphous magnetic alloy thin plate is annealed.

[Technical background of the invention and its problems]

Recently, the use of amorphous magnetic alloy thin plates as materials for wound cores and laminated cores used in transformers and the like is being considered. The amorphous magnetic alloy thin plate is made of metal (Fs*Co
・, Ni, etc.) and metalloid elements (B, C, 81, P'
etc.) is manufactured using the ultra-quenching method as the main ingredient.
Compared to silicon steel sheet, which is a conventional iron core material, iron loss is small at IA to 1/4, and it has excellent magnetic properties.

However, since amorphous magnetic alloy thin sheets are manufactured using an ultra-quenching method, their magnetic properties are extremely degraded due to distortion during quenching, such as increased core loss, and their original excellent magnetic properties are not achieved. I can't do it. For this reason, iron cores made of non-quality magnetic alloy thin sheets are subjected to strain relief annealing after core assembly to remove the strain on the amorphous magnetic alloy sheets, thereby improving the original magnetic properties of the amorphous magnetic alloy, such as reducing iron loss. Efforts are being made to restore the characteristics. This annealing is a method for improving magnetic properties by placing an iron core in a magnetic field to impart magnetic anisotropy.

However, when performing this annealing, the following points are important. Amorphous magnetic alloy thin plates have narrow annealing temperature conditions, and if the temperature is not raised to make the temperature distribution inside the core uniform, the magnetic properties will deteriorate due to thermal stress and it will be difficult to recover the original excellent magnetic properties. It is not possible to aim for In addition, since amorphous magnetic alloy thin sheets have the property of becoming brittle after annealing, when handling the iron core after annealing, the amorphous magnetic alloy sheets may be damaged by external force (creating cracks or fragments). Carelessness such as causing dielectric breakdown during use is unfavorable in terms of the quality of the iron core. Therefore, it is necessary to assemble the iron core before annealing to reduce the number of assembly steps after annealing and to reduce the chances of external force being applied to the amorphous magnetic alloy plate.

In this case, the work of winding the transformer coil around the iron core places a large degree of stress on the iron core.

Conventionally, for annealing an iron core made of an amorphous magnetic alloy thin plate, a method has been adopted in which the iron core is heated by an external heat source. That is, as shown in FIG. 8, a coil 3 for applying a magnetic field is wound around an iron core 1 made of an amorphous magnetic alloy plate 2, for example, a wound iron core made by winding an amorphous magnetic alloy thin plate 2. is housed inside a constant temperature bath 4 whose heat source is an electric heater (not shown). Then, a DC current is applied to the coil 3 by the DC power supply 5 to apply a magnetic field to the iron core 1, and the inside of the constant temperature bath 4 is raised to a predetermined annealing temperature by heating with an electric heater to heat the iron core J. Annealing is performed by this.

The annealing temperature of the amorphous magnetic alloy material varies depending on the type, but for Allied's Seiro TGLAS2605S2, which is currently considered the most suitable material for transformer core materials, the annealing temperature is 3.
Approximately 90 to 410°C is appropriate. Further, it is considered appropriate that the annealing temperature is maintained for about 2 hours.

However, in such an annealing method, the iron core 1
Since the iron core is heated from the outside by radiant heat from an electric heater as a heat source, the inside of the iron core is not properly heated, and the temperature distribution on the surface and inside of the iron core 1 becomes uneven. Therefore, the magnetic properties of the amorphous magnetic alloy thin plate 2 of the iron core 1 deteriorate due to thermal stress, and it is difficult to restore the original magnetic properties. Further, the iron core 1 is heated to a predetermined annealing temperature using an electric heater, that is, 4
In order to heat the core to about 00℃, the temperature inside the constant temperature 41F4 will also rise to the same temperature, so if the iron core 1 around which the transformer coil is wound is placed inside the constant temperature bath 4 and annealed,
The transformer coil is also heated externally to 400°C.

However, the insulation used for the insulation coating of transformer coils and coils generally has a low heat resistance limit (if heated to a temperature of 400°C, the insulation will be damaged and become unpractical. In the process before annealing, a transformer coil is wound around the iron core 1,
It is difficult to perform annealing after that because it will damage the transformer coil, and the iron core IVc transformer coil will be wound in the process after annealing.However, the iron core after annealing
Since this is accompanied by the embrittlement phenomenon of the amorphous magnetic alloy material 2, if the assembly work of winding the transformer coil around the iron core 1 is performed after annealing, the chances that the amorphous magnetic alloy thin plate 2 will be damaged by external force will increase. As a result, the quality of the iron core 10 will be degraded.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and is capable of efficiently annealing an iron core made of an amorphous magnetic alloy thin plate, thereby achieving a quality that can fully exhibit the excellent magnetic properties inherent to the amorphous magnetic alloy. The object of the present invention is to provide a method for manufacturing an iron core that can obtain a good iron core.

[Summary of the invention]

The method for manufacturing an iron core of the present invention involves covering the surface of the iron core made of an amorphous magnetic alloy thin plate with a heat reflecting material, covering the outside of this heat reflecting material with a heat insulating material, and applying an excitation alternating current to a coil wound around the iron core. An electric current is passed through the core to excite it, and the loss that occurs in the core due to this excitation causes the core itself to generate heat and heat up, thereby annealing it. That is, when annealing a core made of amorphous magnetic alloy thin plate, the core can be heated with a uniform temperature distribution and can be annealed without damaging the transformer coil wound around the core. This reduces assembly man-hours. In addition, by covering the iron core with a heat reflective material that has a low absorption rate of thermal radiation and surrounding the outside with a heat insulating material, the radiation and convective heat radiation of the heat generated by the iron core can be effectively suppressed and accumulated inside. In addition to quickly annealing the iron core, it is possible to lower the surface temperature of the heat insulating member and protect the transformer coil from the heat of annealing.

[Embodiments of the invention]

Embodiments of the present invention shown in drawings will be described below. Figures 1 to 4 show an embodiment of the method of the present invention. In this embodiment, two sets of amorphous magnetic alloy thin plates are wound. The target is one in which the cores are lined up and a transformer coil is wound around the center leg of each core.

The wound core 11.11 is formed by winding a strip-shaped amorphous magnetic alloy thin plate 12 into a rectangular shape.

Each winding core 37. The surface of '22 is covered with heat reflective material 13 and 14 shown in Figs.
3. The outside of J4 is surrounded by a heat insulating member 15°16. In this embodiment, the heat insulating members 15 and 16 are used as frame members, and a heat reflecting member 13°J4vl- is combined with this. As shown in FIG. 3, the heat insulating member J5 includes a rectangular cylindrical portion 25m surrounding the inner circumferential surface of the wound core 11, and seven rung portions formed at both ends of the cylindrical portion 15 and surrounding both end surfaces of the wound core 11. 15b, 1
5b, and can also serve as a winding form for winding the amorphous magnetic alloy thin plate J2. Cylinder part 1 of heat insulating member J5
Wound core 110 at 6m and 7 rung portions 15b and J6b
A sheet-shaped heat reflecting material 13 is provided on the inner surface facing the surface.
are superimposed and glued together. In addition, 17 in the figure is a spacing insulator, which is 7 runs 2 part 15 b, 11 of J5b.
It is attached to IJrfJ through a plurality of heat reflecting materials 13'ft apart. As shown in FIG. 4, the heat insulating member 16 has a rectangular cylindrical shape surrounding the outer peripheral surface of the wound core JJ. On the inner surface of the heat insulating member 16 facing the outer circumferential surface of the wound core J1, a sheet-like heat reflecting sheet #'J4 is superimposed and adhered. The heat insulating members 15 and 16 are made of a heat insulating material having low thermal conductivity and heat resistance capable of withstanding heat of 400° C. or higher, which is the annealing temperature of the wound core 11, such as alumina (At203) and silica.

(sio□)"fc A molded article made of ceramic fibers melted into fibers is used. The heat reflecting material 13°J4 is formed using aluminum, brass, copper, etc. as a material with a low heat absorption rate. Then, the cylindrical portion J of the heat insulating member 15
Amorphous magnetic alloy ribbon 12 is wound around I5m to form wound core 11.
To form K, the inner circumferential surface and both end surfaces of the wound core 11 are covered with a heat reflecting material 13, and the outside of the heat reflecting plate 13 is surrounded by a heat insulating member J5. Note that an air layer is formed between both end faces of the wound core 11 and the □ heat reflecting material 13 by the spacer insulator 17 . Furthermore, by covering the wound core 32 with the heat insulating member 16, the outer peripheral surface of the wound core 11 is covered with the heat reflecting material 14, and the outside of the heat reflecting plate 14 is surrounded by the heat insulating member 16.

Next, in a pre-process of annealing the wound core 11.11,
A transformer coil J8 is commonly wound around the outer side of a heat insulating member 75.15 that surrounds the central leg of the wound cores 71.11.

Then, when annealing the wound core J J '# J 9# Wind each of J y f (tentative winding). These pre-wound coils 19, 19 are wound in opposite winding directions, and are connected to a high frequency AC power source 21 and a DC power source 22 via a switch 20, respectively. In the figure, 28 is a voltage regulator that adjusts the voltage of the high frequency AC power supply 21.

By using an inorganic insulated wire, such as a ceramic wire, for the temporary winding coils 19 and 19, sufficient voltage and heat resistance can be obtained.

Here, since a voltage is applied to the temporarily wound coil 29.79 according to the number of turns, the number of turns is small and the number of turns is selected so as to cause no problem in terms of dielectric strength.

Then, in order to anneal the wound iron core rye"iz,
The temporary winding coils 19, . 19 is connected to the high frequency AC power supply 21 side, the stain pressure is adjusted by the voltage regulator 28, and a high frequency AC current for excitation is applied to the temporary winding coil J9.19. Frequency of this alternating current #i2~4k
Hz. When an alternating current is passed through the temporary winding coil 19.19, an eddy current flows through the winding core 11.11 due to the generation of magnetic flux.
i, Joule heat is generated in IJ.

For this reason, the t-turn iron cores lj and JJ are heated by their own internal heat generation and their temperature rises. The temperature of the wound core J7, 21 is 400°C, which is the appropriate annealing temperature of the amorphous magnetic alloy thin plate 12.
If the voltage rises to C, the voltage regulator 28 turns off the high frequency AC power supply 2.
By adjusting the voltage of , the temperature of the wound core 11.11 is kept constant at 400° C. for an appropriate temperature holding time. This temperature holding time is 30 minutes to 2 hours. Note that 1 temporary winding coil 19. Since L9 is connected with opposite polarity,
By passing an alternating current through the temporarily wound coil 19.19, the wound iron core 1x,
11t-When energized, the compound-wound core 27. The directions of the magnetic fluxes in the central legs of the JJ are opposite to each other, and no induced voltage is generated by the magnetic flux in the transformer coil J8 wound around the central legs. The same effect can also be obtained by connecting the temporary winding coils 19, 19 in reverse series with each other.Next, when the changeover switch 20 is operated, the temporary winding coils 19, 19 are disconnected from the AC power supply 18 side. Connect to the DC power supply 22 side. Therefore, the supply of alternating current to the pre-wound coils 19 and 19 is interrupted, and the winding core J J t'
The excitation of JJ stops, and the wound cores JJ and JJ start cooling. At the same time, a DC current is supplied from the DC power supply 22 to the temporary winding coil 1.
9°1.9, forming a magnetic field around the wound cores JJ and JJ. In this way, the wound core 11. It is cooled in a magnetic field. In this case, since there is no external heat source, the heat capacity is small, and the cooling rate can be easily controlled. After annealing, the pre-wound coil 19.
Remove from 7.

Note that the annealing work is preferably performed in an inert gas atmosphere, for example, nitrogen gas (N2) in order to prevent oxidation of the wound core JJjJi.

In this manner, the wound core 11.11 is annealed.

When heating the wound cores 11 and 21 in this annealing method, the temperature of the wound cores JJ, JJ increases due to heat generation from within itself due to loss due to high frequency heating.
The entire wound core 11, 11 can be heated sufficiently and uniformly, and the temperature distribution on the surface and inside of the wound iron core 21 can be made uniform. Therefore, distortion due to thermal stress does not occur in the amorphous magnetic alloy thin plate 12 of the wound core Jx, i1, and deterioration of its magnetic properties can be prevented. In addition, the heating method for the wound cores J J , J, and J is wound core 71. [7] It is a method in which the wound core 1.1. ,．．
1.1 It is not a method of heating the entire product from the outside to the annealing temperature. Therefore, when heating the wound core 11, 1lt, the transformer coil 18 wound around the wound core 11°11 is not forcibly heated from the outside to the annealing temperature (400°C), and the transformation due to high temperature is prevented. Damage to the device coil 18 can be prevented.

Next, a heat reflecting material JJ, 24 covering the surface of the wound core J1, JJ, and a heat insulating member J5 surrounding the outside thereof. The effect during the annealing process of J6 will be explained.

The heat reflecting materials 13 and 14 suppress heat dissipation due to radiation from the wound core 11, and the heat insulating members 15 and 16 suppress heat dissipation due to convection from the wound core 11, and store the heat generated by the wound core 11. It is. The heat reflecting materials 13, 14 and the heat insulating members 15, 16 suppress the release (heat radiation) of the heat generated by the wound core 11 during annealing, accumulate heat inside the core, and raise the temperature of the wound core 11 in a short time. It is made possible to perform annealing by raising the temperature.

To explain, when the wound core 11 is excited to raise the temperature of the wound core J1 by its own heat generation, part of the heat is radiated from the wound core 11, and the other part is stored inside the wound core 1. Ru.

Here, if the amount of heat generated by the wound core 11 is Q s (k''), the amount of heat dissipated from the wound core 1 is Q z (km), and the amount of heat stored inside the wound core 1 is Q s (km), then Qs=Q
IQt...(1).

Q*-Q2 JQl is expressed by the following formula.

Ql = k1wqt t - (
2)...(3) Qs = CW(--θco)
-(4) Also, the amount of temperature drop T (° C.) of the heat reflecting material 13.14 and the heat insulating member 13.14 covering the wound core J1 is as follows. However, kx*ks-: Proportionality constant W; Weight of wound core (kg) ql; Calorific value per unit weight of wound core, unit time kc
ai/kg-h t ; Time for energizing the coil (h) g ; Acceleration of gravity (%/s2) β ; Expansion coefficient of atmospheric gas ν ; Kinematic viscosity coefficient of atmospheric gas (trV/s) t : Wound core Typical length of −) 'Pr'', Prandtl number θ68.θ.2; Heat reflector temperature diagram and insulation member surface temperature CC) θ.; Stationary atmosphere temperature CC) Ac; Heat dissipation area due to convection (fi) Ar ; Heat dissipation area due to radiant heat (m2) C; Specific heat of wound core (kW ■) θ.; Average temperature of wound core (°C) σ; Stephan-yy Lullmann constant 61; Core surface emissivity e2; Heat reflector emissivity F; View factor δ1, δt*Js: Thickness of air layer between core and heat reflector, thickness of heat reflector, thickness of heat insulating member λ1.λ8.λ8; Heat conduction of atmospheric gas, heat reflector and heat insulator rate (k(III!/m-h・℃)W; heat flow density (km/h-m2) As can be seen from these formulas, the average temperature of the wound core is 40
In order to effectively use the heat generation amount Q1 as the heat storage amount Qs in order to raise the temperature to about 0° C., the heat radiation amount Q3 should be made small. Therefore the heat reflector is.

14 and heat insulating members J'5, 76 to suppress heat radiation from the wound core 11, the amount of heat generated can be effectively stored inside the wound core J1.

Here, heat reflective material 13. The suppression of radiant heat radiation by δ4 and the suppression of convective heat radiation by the heat insulating member 1.5+16 will be described. First of all, regarding thermal radiation, Kirch and Hopf's law regarding thermal radiation, 5-1 When thermal radiation emitted from a surface at a constant temperature is projected onto another surface at the same temperature, The rate a is approximately equal to the emissivity 8 of that surface. Therefore, if the heat reflecting plates 13 and 14 are made of a material with small radiation and weight resistance ε=, then the second equation of the above equation (3) Heat dissipation due to radiation can be suppressed by reducing the amount of heat dissipated by radiation. As mentioned above, aluminum, brass, copper, etc. are suitable materials for the heat reflecting plate JJ, 74), and the emissivity can be lowered by polishing the reversed surface. The amount of radiant heat dissipated can be IA to 1/30 of that of a physical object. Next, regarding convective heat radiation, the heat insulating member J 5 , 2.6 is
The surface i degree θ is expressed in terms. It is necessary to make it low (for this reason, the heat soaking shown in the above equation (5), the conductivity λ3 is small h material,
Furthermore, a material that can withstand temperatures of 400°C is used. For example, the upper 2 mix fiber used in the above example has sufficient heat resistance, and the thermal conductivity varies depending on the composition ratio of alumina and silica, but it is 0.05 to 13 (
km/mhtl:), and a sufficient temperature drop can be expected. Regarding this temperature drop amount, for example,
When the cross-sectional dimension t-0, 1 (to) This results in a temperature drop of 300 dsg. Therefore, the surface temperature θ of the heat insulating member 13.14
. is approximately 100°C or less, and according to equation (3), the amount of heat dissipated from the wound core 11 is approximately 174, and the calorific value can be effectively stored inside the wound core 11. An air layer is formed between both end surfaces of the wound cores 1 and J and the heat reflecting plate 13. For this reason, the annealing temperature is 400
Thermal conductivity of atmospheric gas around °C λ1 # 0.044
km/m-h ・℃, air layer thickness δ1 = 0.001
Even if the heat generation value of the 2N% iron core is 200 km/h-kli+, the temperature drop of the insulation member 25.16 is approximately 10, Odeg.
becomes.

In this way, the heat reflecting material J'J, 14 and the heat insulating member J5t
When J6 stores the heat generated by the wound core 110 inside the wound core 11, from equation (2), the amount of heat generated per unit time of the core unit weight W1 is q! When each of these is constant, the time t for applying current to the pre-wound coil 19 required to raise the temperature of the wound core 11 to about 400° C. is significantly shortened, and annealing can be performed efficiently. Furthermore, if the energization time t to the temporary coil 19 is constant, the above-mentioned heat generation amount q1 can be made small, and the frequency f can be made low because q = fn - Bn. In some cases, the advantage is that equipment with a small power supply capacity is sufficient. Furthermore, when the amount of heat dissipated from the wound core 11 is reduced, the temperature distribution inside the core is more evenly distributed. Furthermore, since the surface temperature of the heat insulating members 15 and 16 can be suppressed to a low level, that is, below the heat resistance temperature of the insulator as described above, the wound iron core 13. Transformer coil J wound around IJ
8t - Thermal damage to the insulators in the vicinity of the wound core 11゜4 J can be prevented, and there is no need to use heat-resistant grade scraps for these insulators. Additionally, the surface of the wound core 1 is covered. The heat reflecting plate λ3゜14 and the heat insulating member 15.16 are made of the wound core 1 which has become brittle due to annealing.
It has the role of reinforcing and protecting the amorphous magnetic alloy thin plate 12 of No. 1. Therefore, when an external force is applied to the wound core 11 assembled as the contents of the transformer, the amorphous magnetic alloy thin plate 12 can be prevented from being damaged, and dielectric breakdown due to fragments of the thin plate can be prevented.

Furthermore, the heat insulating members 13 and 14 have the role of absorbing and insulating noise generated from the wound core 11 made of the amorphous magnetic alloy thin plate 12.

That is, since the amorphous magnetic alloy thin plate has a larger magnetostriction than the conventional silicon steel plate, the wound core IJ generates noise due to this magnetostriction. In general, sound absorption is caused by mechanical loss due to friction due to the movement of air particles and vibration of the sound absorption layer, i.e., part of the sound is heat, etc.
Heat insulating member J5 made of fiber. Since J6 has a large amount of microspaces between fibers, it has a high sound absorption coefficient and can reduce the increase in sound pressure due to diffuse reflection of sound between members facing the surface of the wound core 11. In addition, the sound insulation effect of the heat insulation member J'5.76 is based on the law of mass, and there is sound reduction due to transmission loss according to the surface density. 16 have. This has the effect of reducing the noise generated not only during transformer operation but also when the winding core 7 is annealed by high frequency excitation, and this effect is particularly noticeable in the high frequency range.

Next, another embodiment of the present invention will be described. FIGS. 5 and 6 show another embodiment of the heat insulating member. Fifth
The heat insulating member 25 shown in the figure surrounds the outer peripheral surface and both ends of the wound core 11, and has a two-part structure. A heat reflecting material 23 and a spacing insulator 27 are provided on the inner surface of the heat insulating member 25.

A heat insulating member 26 shown in FIG. 6 surrounds the inner peripheral surface of the wound core IJ, and a heat reflecting material 24 is provided on the outer surface thereof.

FIG. 7 shows the cross section rMt of the wound core in yet another different embodiment. In this embodiment, as in each of the above embodiments, a spacer insulator J is provided on the inner surface of the heat insulating member 1B (2B).
v (pv), and both end faces of the wound core 11 and the heat reflecting material J
3 (23), instead of forming an air layer between the insulation member xi (:ts
) has a structure in which the heat reflecting material xs (zs) provided in the winding core J1 is brought into direct contact with both end surfaces of the wound core J1.

In this structure, each end face of the amorphous magnetic alloy thin plate 12 wound as the wound core IJ is short-circuited to the heat reflecting material It is possible to increase the eddy current loss generated in the well-wound core JJK, increase the heat generation inside the core, and further shorten the energization time required to raise the temperature of the wound core 11 to about 400° C. for the same core weight. It is possible to lower the power supply frequency and reduce the power supply capacity. The eddy current loss W when the end face of the wound core IJ is short-circuited is calculated as follows: where t is the thickness of the amorphous magnetic alloy thin plate 22, n is the number of turns of the thin plate, and α is a coefficient determined by the degree of end face short-circuiting. , W@ol: (αn1)2·f2, so by shorting the end face, the eddy current loss increases by a large 1[K. In addition, when assembling the wound core 11 as a transformer, remove the heat reflecting plate that short-circuits the end face to avoid an increase in eddy current in the wound core J1 during transformer operation. When assembling it, remove the insulation members J5 (25), 16 (
26) may be removed.

The heat insulating members are not limited to those made of ceramic fibers, but may also be made of heat-resistant heat insulating materials such as glass fibers, rock cool fibers, and asbestos. The molded product is not limited to the one shown, but may also be constructed by wrapping a tape-like material around the wound core J7, or by wrapping a sheet-like material over the wound core J7. Although a temporarily wound coil temporarily wound around a wound iron core is used to excite the iron core at high frequency, the present invention is not limited to this, and a transformer coil wound around a wound iron core may also be used. However, in this case, there is a problem with the insulation of the transformer coil in high-voltage applications, so it can be used in low-voltage transformers.

In addition, in order to apply a DC magnetic field to the first core when cooling the core, in addition to using a temporary winding coil, it is also possible to use a transformer coil. It is also possible to apply a DC magnetic field to the wound core during this process.

The core to be annealed is not limited to a wound core, and the same effect can be obtained with a laminated core made of laminated amorphous magnetic alloy thin plates.

When annealing is performed, it is advantageous in terms of quality and manufacturing to wind the transformer coil around the core. However, the present invention is not limited to this, and it is also possible to wind the transformer coil around the iron core and perform annealing without winding the transformer coil.

〔Effect of the invention〕

As explained above, according to the method of manufacturing the iron core of the present invention,
By exciting an iron core made of an amorphous magnetic alloy thin plate and generating heat in the iron core itself, it is possible to increase the temperature of the iron core with a uniform temperature distribution and perform annealing. can prevent deterioration of magnetic properties. The heat reflecting material covering the surface of the core suppresses radiant heat from the core, and the heat insulating material surrounding the outside of the heat reflecting plate suppresses convective heat radiation from the core, effectively distributing heat inside the core. The iron core can be annealed quickly. Also, exciting the wound iron core to generate heat,
Due to the heat insulating effect of the heat reflector and the heat insulating member and the K, it is possible to perform annealing without damaging the transformer coil even when the transformer coil is wound around the iron core, reducing the number of assembly steps required after annealing. , it is possible to prevent damage due to embrittlement of the amorphous magnetic alloy thin plate.

Therefore, a high quality iron core with excellent magnetic properties can be obtained. Furthermore, the heat reflecting material and the heat insulating member have the effect of increasing the rigidity of the iron core made of the amorphous magnetic alloy thin plate and suppressing the noise generation of the iron core.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of the method for manufacturing a wound core using the FIi1 of the present invention, Fig. 2 is a cross-sectional view of the wound iron core shown in Fig. 1, and Figs. An example of a reflective material is shown in Figure 3 (a) (b) and Figure 4 (,) (b) are perspective views and cross-sectional scales, respectively, and Figures 5 and 6 are heat insulating members and heat reflectors. Another example of the material is shown in Figure 5 (,) (b
) and 6(,)(b) are respectively a perspective view and a cross-sectional view, FIG. 7 is a cross-sectional view showing the state of contact between the core and the heat reflecting material, and FIG. 8 is a conventional method for manufacturing a wound core. FIG. 1... Iron core, 2... Amorphous magnetic alloy thin plate, 11...
・Wound core, 12...Amorphous magnetic alloy thin plate, 13.14
...Heat reflecting material, 15.16...Insulating material, 17...
- Spacing insulator, 18...Transformer coil, 19...Temporarily wound coil, 20...AC power supply, 2...DC power supply,
23° 24... Heat reflecting material, 25.26... Heat insulating member, 27... Spacing insulator. District 1, Figure 2

Claims (1)

[Claims] The outer surface of the iron core made of amorphous magnetic alloy thin plate is covered with a heat reflecting material, and the outside of this heat reflecting material is surrounded by a heat insulating material.
A method for manufacturing an iron core, characterized in that the iron core is excited by passing an excitation alternating current through a coil wound around the iron core, and the iron core itself is heated and annealed by a loss generated in the iron core due to this excitation.