JPS60233811A - Heat treatment of wound core - Google Patents

Abstract

PURPOSE:To make an annealing temperature uniform by previously forming a dielectric layer between the wound layers of an alloy thin belt and on the surface of an iron core and by heating applying voltage to the dielectiric layer from electrodes provided on both the inside and the outside surfaces and the sides of the iron core in annealing a wound core wound with an amorphous magnetic alloy thin belt. CONSTITUTION:A cirular wound core 11 is wound with an amorphous alloy thin belt 12. The wound core 11 is removed distortion and annealed in magnetic field. In this construction, a dielectric layer 13 is formed in all circular directions between the wound layers of the alloy thin film 12 and on the external and the internal sufaces an on both the side end surfaces of the iron core 11. In this case, such a material as epoxy resin which has great dielectric dissipation factor against high frequency voltage is used for the dielectric layer 13 and circular ring electrodes 14 on the external and the internal surfaces and circular plate electrodes 15 on both the end surfaces of the iron core 11 are provided. Then, the iron core 11 is put in an annealing furnance, high frequency voltage is applied to the electrodes 14 and 15, simultaneously, magnetic field is generated from a coil around the iron core 11 and the iron core 11 is heated at approx. 400 deg.C.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a heat treatment method for a wound core made of an amorphous magnetic alloy ribbon. For the wound core to be used, it is being considered to fabricate it with an amorphous magnetic alloy material that has excellent low loss characteristics. This amorphous magnetic alloy material is made of iron,
It is a thin strip produced by an ultra-quenching method using an alloy consisting of metals such as cobalt and elements such as boron and carbon.
Compared to silicon steel sheet, which is a conventional iron core material, it has significantly lower iron loss and excitation current, and has excellent magnetic properties.

However, since the amorphous magnetic alloy ribbon has residual internal stress generated when it is manufactured by the ultra-quenching method, it cannot fully exhibit its excellent low loss characteristics if used as is. Therefore, when manufacturing a wound core using an amorphous magnetic alloy ribbon, after forming the wound core, annealing is performed in a magnetic field to remove internal stress. This makes it possible for the robot to demonstrate its unique characteristics.

In this case, the annealing temperature of the amorphous magnetic alloy ribbon is approximately 400°C.
The temperature range is 10 as shown in the diagram in Figure 2.
~20℃, which is relatively narrow. Therefore, in order to fully demonstrate the characteristics of the amorphous magnetic alloy ribbon, it is necessary to maintain a uniform temperature in each part of the amorphous magnetic alloy ribbon that forms the wound core.
It is necessary to suppress the variation in temperature of each part to within 20°C to avoid local heating.

In the annealing method that has been attempted in the past, as shown in FIG. Electricity is supplied from a power source 5 to cause the electric heater 3 to generate heat, and the wound iron core 1 is heated by the radiant heat from the electric heater 3.

In this case, a magnetic field generating coil 6 for generating a magnetic field is wound around the wound iron core 3.

However, in this annealing method, since the magnetic field generating coil 6 is wound around the surface of the wound core 1, heat transfer from the space to the wound core 1 is suppressed.

Further, even if the surface temperature of the wound core 10 rises, the temperature inside the wound core 1 does not rise immediately, so that temperature non-uniformity occurs due to differences in the location of the wound core 1.

As a result, the temperature difference between the surface and the inside of the wound core 16 exceeds 20°C and reaches as much as 25°C. When the inside of the wound core 1 reaches the appropriate annealing temperature, there is a possibility that the surface temperature of the wound core 1 has already exceeded the appropriate annealing temperature. When the annealing temperature exceeds the appropriate temperature, the amorphous magnetic alloy ribbon has problems in that its low loss characteristics deteriorate and it becomes easily oxidized and becomes brittle.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and includes a wound core made of an amorphous magnetic alloy ribbon that can be well annealed to exhibit the excellent low loss properties of the amorphous magnetic alloy material. The present invention provides a method for heat treating a wound iron core that can be obtained.

[Summary of the invention]

In the method for heat treatment of a wound core according to the present invention, a dielectric layer is formed in advance between the winding layers of an amorphous magnetic alloy ribbon and on the surface of the wound core, and the surface of the wound core is brought into contact with the dielectric layer. The method is characterized in that an electrode is attached, a voltage is applied to the dielectric layer through the electrode, and the resulting heat generated by the dielectric layer heats the amorphous magnetic alloy ribbon to perform annealing.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to drawings.

An embodiment in which the present invention is applied to a circular wound core will be described with reference to FIGS. 3 and 4. FIG.

First, the amorphous magnetic alloy ribbon 12 is wound to form a circular wound core 11 .

Next, the wound core 11 is subjected to strain relief annealing in a magnetic field. During this annealing, a dielectric layer is formed inside and on the surface of the wound core 1, and electrodes are attached to the surface of the wound core 11 via the dielectric layer. In this embodiment, a dielectric layer 13 is formed in the entire circumferential direction between each wound layer of the amorphous magnetic alloy ribbon 12 in the wound core 11, and a dielectric layer 13 is formed on the outer peripheral surface and the inner periphery of the wound iron core 1. A dielectric layer 13 is formed all over the circumferential direction on the surface and both end surfaces.

The dielectric layer 13 has -α (dielectric voltage contact) with respect to the high frequency voltage.
Use a dielectric material with a high resistance, such as epoxy resin or polyester resin. Dielectric layer 7 between the winding layers of the amorphous magnetic alloy ribbon 12 and on the inner and outer peripheral surfaces of the wound iron core 11. ? ld,
It is formed by coating one or both sides of the amorphous magnetic alloy ribbon 12 with a dielectric material before forming the wound core 11. The dielectric layer 13 on both end faces of the wound core 11 is
It is formed by coating both end faces of the core with a dielectric material.

Furthermore, annular electrodes 14.14 are attached to the outer and inner peripheral surfaces of the wound core 11 in contact with the outer surface of the dielectric layer 13, and disk-shaped electrodes 14.14 are attached to both end surfaces of the wound core 11. An electrode 15.15 is attached in contact with the outer surface of the dielectric layer 13.

The electrodes 14,15 are made of, for example, an iron-nickel alloy and are attached to the wound core 1 by taping or wrapping in a heat-resistant insulating material such as Kabuton.

The wound core 11 prepared in this manner is placed inside the annealing furnace 16. Each of the electrodes 14, 14 and J5, 15J7 attached to the wound core 11 is connected to a wave power source 17, and a magnetic field generating coil 18 connected to a power source 19 is wound around the wound core 1.

Then, each electrode 14, 14 and 1 provided on the wound core 1
5.16, apply a sine wave or distorted AC voltage of about 1 kT (about z) to the high frequency power source 17. Then, each electrode 1
Electricity is applied to each dielectric layer 13 formed on the wound core 11 through angles 4.14 and 15.degree. 15, and the dielectric layers 13 generate heat, thereby heating the wound core 11. In this case, the dielectric layer 13 is formed between the inner and outer peripheral surfaces and end surfaces of the wound core 11 and the wound layers of the amorphous magnetic alloy ribbon 12. Therefore, the amorphous magnetic alloy ribbon 12 constituting the wound core 1) is heated uniformly on the surface and inside each portion of the wound core 11 due to the heat generation of each dielectric layer 13. Ru. For this reason, the amorphous magnetic alloy ribbon 1 in each part of the wound core 11
2, the temperature rises uniformly to reach the desired appropriate annealing temperature (approximately 400°C), and the temperature variation in each part is reduced by 20°C.
It can be kept within ℃. In this way, winding core 1
1 can be uniformly annealed within an appropriate annealing temperature range.

In addition, if an inert gas is sealed inside the annealing furnace 16 and the cine active gas is heated to the appropriate annealing temperature by the electric heater 20 provided inside the annealing furnace 16, the heat will be absorbed when the wound iron core generates heat. Dissipation can be suppressed. In addition, the annealing furnace 16
By providing electromagnetic shielding material 2 inside, electrode 1
High frequency electromagnetic waves generated at 4.14 and 15.15 can be reflected.

A voltage is applied to the magnetic field generating coil 18 from a power source 19 to form a magnetic field around the wound core 1.

Here, an example of annealing the wound core 11 will be described. The annealing conditions are as follows. Frequency of applied voltage f =
10'Hz, electric field strength E=100V/m. The width of the wound core 11 is 2.5 crn1, the thickness is 25 crn1, and the specific gravity is 77.
The average magnetic path length is 306n. The dielectric layer (polyester resin) 13 has -α600 and a relative dielectric constant of 65.2. The dielectric loss P per 1(7)3 of the dielectric layer 13 is: P=tanXfXgXtanαx E"X 10 W/c
According to the above conditions, P=-xlxlo x5.2x600X100 xio
-2=17.3 W/cm3.

The internal heat generation of the wound core 11 will be described. Thickness 0.01c
Dielectric layer 13f of rn: When 30 layers are formed between the layers of the amorphous magnetic alloy ribbon 12, the volume V of the dielectric layer 13 is: V=0.01X30X2.5X30=22.5crn"
It is. As a result, total loss PFiP=17.3×22
．． 5=390W. The volume U of one wound core is U=2
．． 5×2.5×30=188cm3, and the M amount W is W=UX7.7=1444r. The specific heat of the wound core horn is set to 0.48 J/f, and the voltage application time is set to 1 second.

Assuming that the temperature rise of the wound core 11 is 1°C, T=390/(
0.48×1444)=0.6°C.

Therefore, the temperature of the wound core 1 rises to 400° C. in about 11 minutes. Increasing the frequency of the applied voltage or increasing the electric field strength can reduce the time required for temperature rise.

After finishing the strain relief annealing, the wound core 1 is taken out from the annealing furnace 16, and the electrodes 14.14 and 15.15 are removed from the wound core 1.

In addition, the above-mentioned embodiment shows the case where four electrodes 14.14 and 15.15f are attached to the entire surface of the wound core 11, that is, the inner and outer peripheral surfaces and both end surfaces. The entire surface can be heated evenly from the surface side.

However, the present invention is not limited to this method, and at least a pair of electrodes may be attached to the surface of the wound core 11 to heat the wound core 1.

Furthermore, the present invention is not limited to circular wound cores, and can also be applied to, for example, a circular wound core 11 divided into two as shown in FIG. It can also be applied to iron core 1.

〔Effect of the invention〕

As explained above, according to the method for heat treatment of a wound core of the present invention, each part of the wound core is uniformly heated to an appropriate annealing temperature when strain relief annealing is performed on a wound core made of an amorphous magnetic alloy ribbon. By heating and performing good annealing, it is possible to obtain a wound core that can exhibit the excellent low loss characteristics of an amorphous magnetic alloy material.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional example of annealing a wound core, FIG. 2 is a diagram showing the relationship between the excitation capacity of an electric heater and the temperature of the wound core when annealing a wound core, and FIGS. 4 each shows an embodiment of the method according to the invention;
FIG. 4 is a cross-sectional view showing the wound core, and FIGS. 5 and 6 are perspective views showing other examples of the wound core. 11...Wound core, 12...Amorphous magnetic alloy ribbon, 1
3°'°dielectric layer, 14.15...electrode, 16...
Annealing furnace, 17... High frequency power supply, 18... Magnetic field generating coil, 20... Electric heater. Applicant's representative Patent attorney Takehiko Suzue 2 IL: 5 degrees (cl) Commissioner of the Patent Office Manabu Shiga 1, Indication of the case Patent application No. 1985-85620 2 Name of the invention Method for heat treatment of rolled iron core 3 , Relationship with the case of the person making the amendment Patent applicant (307) Toshiba Corporation 4, Representative 1 Tlj person 6, Specification subject to amendment 7, Contents of amendment (1) Specification page 5, line 18, line 8 In the 15th line and 18th line of the page, replace "taJlα" with "-δ" respectively.
I am corrected. (2) U on page 5, line 18 or line 19 of the specification
(Dielectric voltage #:)" should be corrected to "(Dielectric loss tangent). (8) In the second or third line of page 7 of the specification, "l k
1-1zJ is corrected to [IMH2J.

Claims (1)

[Claims] A method of annealing a wound core formed by winding an amorphous magnetic alloy ribbon, wherein a dielectric layer is preliminarily applied between the winding layers of the amorphous magnetic alloy ribbon and on the surface of the wound core. An electrode is attached to the surface of the wound core in contact with the dielectric layer, and a voltage is applied to the dielectric layer through this electrode, and the amorphous magnetic layer is heated by the dielectric layer. A method for heat treating a wound iron core, characterized by heating and annealing an alloy ribbon.