JPS6159812A - Manufacture of core - Google Patents

Abstract

PURPOSE:To display magnetic characteristics original to an amorphous magnetic alloy by arranging magnetic material bodies having a Curie point higher than an amorphous magnetic alloy metal sheet among the layers of a core in which the amorphous magnetic alloy metal sheet is wound or laminated, high-frequency exciting the core and heat-generating and annealing core itself by loss generated by the high-frequency excitation. CONSTITUTION:Exciting coils 14 are connected to a high-frequency AC power supply 16 by a changeover switch 15, and voltage is adjusted by a voltage regulator 18 and the high-frequency AC power supply is flowed through the exciting coils 14. The frequency of the AC power supply is selected to 1kHz or higher such as 2-4kHz. When the AC power supply is flowed through the exciting coil 14, eddy currents flow through amorphous magnetic alloy metal sheets 12 and magnetic material bodies 13 in a wound core 11 by the generation of magnetic flux, and the temperature of the amorphous magnetic alloy metal sheet 12 rises by its own internal heat generation and heating by the heat generation of the magnetic material body 13. When the temperature of the amorphous magnetic alloy metal sheet 12 rises to a proper annealing temperature, voltage is adjusted, the temperature is kept for a fixed time and the whole is annealed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of manufacturing an iron core made of an amorphous magnetic alloy plate used in a transformer, etc., by annealing the iron core.

[Technical background of the invention and its problems]

Recently, consideration has been given to using amorphous magnetic alloy plates as materials for wound cores and laminated cores used in transformers and the like. The amorphous magnetic alloy plate is made of metals (Fe, Co,
Ni, etc.) and metalloid elements (B, C.

Manufactured by an ultra-quenching method using St, P, etc.) as the main ingredients, the iron loss is 1/3 to 1/4 smaller than that of silicon steel sheets, which are conventional core materials. , has excellent magnetic properties.

However, since amorphous magnetic alloy plates are manufactured using an ultra-quenching method, their magnetic properties are extremely degraded due to strain during quenching, including increased iron loss, making it impossible to obtain the original excellent magnetic properties. do not have. For this reason, iron cores made of amorphous magnetic alloy plates are subjected to strain relief annealing after core assembly to remove the strain on the amorphous/JJ magnetic alloy plates, thereby reducing iron loss and other properties inherent to amorphous magnetic alloys. Efforts are being made to restore the magnetic properties. This is done by placing an iron core in an acupuncture field to give it magnetic anisotropy (to improve its magnetic properties).

In this case, the range of appropriate annealing temperature conditions for the amorphous magnetic alloy thin plate is narrow. For example, METGLAS260582 (trade name) manufactured by Allied, USA, which is a typical amorphous magnetic material, has an annealing temperature of about 400°C and a narrow temperature range of ±15°C, as shown in FIG. Furthermore, the required annealing time is short; if this time is long, the crystallization of the amorphous magnetic alloy thin plate will proceed. Therefore, in order to strain-relieve an amorphous magnetic alloy thin plate without impairing the excellent magnetic properties inherent to this material, each part of the iron core must be brought to the appropriate annealing temperature range in a short time. Uniform heating is necessary.

Conventionally, an external heating method has been adopted for strain relief annealing of an iron core made of an amorphous magnetic alloy thin plate. That is, the first
As shown in Figure 0, for example, a magnetic field coil 3 for applying a magnetic field to an iron core 1 made of a wound iron core formed by winding an amorphous magnetic alloy thin plate 2.
This iron core 1 is housed inside a constant temperature bath 4 whose heat source is an electric heater (not shown). And DC power supply 5
The annealing is performed by applying a magnetic field to the iron core 1 by applying a direct current to the magnetic field coil 3, and by raising the inside of the constant temperature bath 4 to a predetermined annealing temperature by the heat generated by the electric heater to heat the iron core 1.

However, in such an annealing method, the iron core 1
Since it is heated from the outside by the radiated heat of the electric heater, it is not possible to properly heat the inside of the iron core 1, resulting in uneven temperature distribution between the 16 sides of the iron core and the inside of the iron core 1. Figure 11 shows a wound iron core with a core weight tht 60 kg that is annealed at a temperature of 4 by the conventional annealing method.
FIG. 2 is a diagram showing the relationship between the heating time and temperature rise of the core valley when heated at 00°C. FIG. 12 is a congratulatory map showing three locations where temperatures were measured in the iron core. In Fig. 12, AAil''l: central part of the thin plate winding thickness direction of the iron core l;
Point B indicates the outer periphery in the thickness direction of the thin plate, and point 0 indicates the outer surface of the iron core 1. Note that DA indicates the internal space of the thermostatic chamber 4. According to Fig. 11, after heating the iron core 1 for 3F#f, the temperature at point B of the iron core 1 rises to about 280°C, but at point A, the temperature rises only to about 230°C, and the temperature between the two rises. This results in a temperature difference of approximately 50°C. In addition, the temperature at point D of iron core 1 rises to about 390℃, and the temperature rises to about 1
A temperature difference of 60°C was generated. As described above, the temperature rise on the surface of the iron core 1 is larger than that inside the iron core 1, and the temperature distribution becomes non-uniform throughout the iron core 1. In order to bring the entire core 1 to a uniform temperature, it is necessary to heat the core 1 for a longer period of time, and as a result, the surface of the core 1, where the temperature rises quickly, is exposed to high temperatures for a long time. The magnetic properties of the crystalline magnetic alloy thin plate deteriorate. Therefore, according to the conventional annealing method, it is difficult to heat the entire iron core to a uniform temperature in a short time, and as a result, the magnetic properties of the amorphous magnetic alloy thin plate 2 deteriorate and the original excellent magnetic properties are deteriorated. The problem is that it cannot be recovered.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to successfully perform strain relief annealing on an iron core made of an amorphous amphoteric alloy thin plate to obtain an iron core that can exhibit the excellent magnetic properties inherent to an amorphous magnetic alloy. The purpose is to provide a method for manufacturing iron cores that can.

[Summary of the invention]

The method for manufacturing an iron core of the present invention includes arranging a magnetic material having a high Scicuri point, such as an amorphous magnetic alloy thin plate, between the layers of an iron core made by winding or laminating amorphous magnetic alloy thin plates, and exciting the iron core with high frequency. The generated loss causes the core itself to generate heat for annealing, and the temperature of the entire core can be raised uniformly in a short period of time to perform annealing. In particular, by arranging a magnetic material in the iron core, the power consumption required for high-frequency excitation can be suppressed, the power supply equipment can be downsized, and annealing can be performed economically.

[Embodiments of the invention]

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

FIGS. 1 and 2 show an embodiment of the method of the present invention, and this embodiment is intended for the case where two sets of wound cores are lined up and subjected to strain relief annealing.

First, a band-shaped amorphous magnetic alloy thin plate 12 is wound into a rectangular shape to form a wound core 11. In forming this wound core 11, each time the amorphous magnetic alloy thin plate 12 is wound a predetermined number of turns, a strip-shaped magnetic material 13 is wound around the entire circumferential direction of the core. As a result, in the wound core 11 as a whole, each six magnetic material bodies 13 are located at a plurality of locations with predetermined winding intervals in the winding thickness direction of the amorphous magnetic alloy thin plate 12.
is arranged between the wound layers of the amorphous magnetic alloy thin plate 12 in the circumferential direction of the iron core. The magnetic material body 13 uses a magnetic material having a Curie point higher than that of the amorphous magnetic alloy thin plate 12 (approximately 500 to 550° C.).

This is because, as will be described later, by using a material with a higher Curie point than the amorphous magnetic alloy thin plate 12, the saturation magnetic flux density decreases less due to temperature rise. The magnetic material body 13 is made of amorphous magnetic alloy thin plate 2 with a thickness of about 30 mm.
It is desirable to increase the occurrence of eddy current loss by using a thicker wall than μ). Examples of this magnetic material include grain-oriented silicon steel plates (cucumber 700-800°C,
Average thickness approximately 0. j5 wm ) can be used. A wound core 11 is formed of the amorphous magnetic alloy thin plate 12 on which the magnetic material body 13 is arranged in this manner.

Next, the two wound cores 11 are arranged and the excitation coil 14 is wound around the outer leg of each wound core 11.

The number of turns of the excitation coil 14 is set appropriately. Excitation coil 1
4 is connected to a high frequency or current power source 16 and a direct current power source 17 via a changeover switch 15. In the figure, 1sta is a voltage regulator that adjusts the voltage of the high frequency AC power supply 16.

When strain relief annealing is to be performed on the wound core 11, the excitation coil 14 is connected to the high frequency AC power supply 16 by the changeover switch 15, and the voltage is adjusted to li! by the voltage regulator 18. li
4! ! Then, a high frequency alternating current is passed through the excitation coil 14. The frequency of this alternating current is 1 kHz or more, for example 2 to 4
Select kHz.

When an alternating current is passed through the excitation coil 14, eddy current flows through the amorphous magnetic alloy thin plate 12 and the magnetic material body 13 in the wound core 1 due to the generation of magnetic flux, and the power loss accompanying this eddy current causes the amorphous magnetic alloy thin plate to 12 and magnetic material body 13
heat is generated. Therefore, the temperature of the amorphous magnetic alloy thin plate 12 increases due to its own internal heat generation and heating due to the heat generated by the magnetic material body 13. When the temperature of the amorphous magnetic alloy thin plate 12 rises to the appropriate annealing temperature of 400°C, the voltage of the alternating current is adjusted by the voltage regulator 18 to maintain the temperature at 400'C for a certain period of time.

In this way, the entire amorphous magnetic alloy thin plate 1 of the wound core 1 is
2, the annealing temperature rises to 400°C in a short time with uniform temperature distribution.

Thereafter, the excitation coil 14 is switched from the AC power source 16 to the DC power source 17 by operating the changeover switch 18 . As a result, the wound core 11 is stopped from being excited by alternating current and starts cooling.

At the same time, a DC current flows from the DC power supply 17 to the exciting coil 14, forming a magnetic field with respect to the wound core 1. In this manner, the wound core 11 is cooled in the magnetic field.

In addition, after the annealing of the wound core 1 is completed, the excitation coil 14
(Remove all windings from core 11).

Further, by leaving the magnetic material body 13 disposed on the wound core 11, the rigidity of the wound core 11 can be increased.

Therefore, when the winding core 1 is annealed in this manner, when the temperature of the winding core 11 rises, the heat generated by the magnetic material 13 with a high Curie point (amorphous magnetic alloy thin plate 2) is amorphous. This helps in increasing the temperature of the magnetic alloy thin plate 12, and as a result, the high frequency AC power source 16t can be constructed economically. ``This point will be explained in more detail. In order to raise the temperature of an iron core made of an amorphous magnetic alloy thin plate to an annealing temperature of 400° C., it is necessary to increase the loss generated per unit weight of the iron core to 25 w/9 or more. Figure 3 is from Allied Manufacturing Department TG.
It is a diagram showing the relationship between iron loss and magnetic flux density using the father flow frequency in LAS2605S2 (trade name) as a meter. According to this Figure 3, in order to generate a loss of 25 W/kg or more in an amorphous magnetic alloy thin plate, it is necessary to
It can be seen that it is necessary to have a magnetic flux density of 6000 Gauss or more at a frequency of kHz. On the other hand, the Curie point of a crystalline magnetic alloy is approximately 500 to 550°C, and the appropriate annealing temperature is 40°C.
Q 'CI'! The temperature is relatively close to the Curie point. However, amorphous magnetic alloys have a property that the saturation magnetic flux density decreases as the temperature increases so as to approach the Curie point.

Figure 4 is Allied Company 1! METGLAS2605S2
FIG. 2 is a diagram showing the relationship between the saturation magnetic flux density and temperature, and according to this diagram, the tendency of the saturation magnetic flux density to decrease as the temperature rises can be seen. Due to this property, the amorphous magnetic alloy thin plate may not be able to obtain the magnetic flux density necessary to generate a loss to raise the temperature to an annealing temperature of 400°C. As a countermeasure for this, either increase the current value of the alternating current flowing through the excitation coil, or
Or frequency? It is conceivable to make it higher, but in this case, the amount of power consumed by four high-frequency excitations increases, and the equipment for the variable current power supply becomes larger and more expensive.

Therefore, in the manufacturing method of the present invention, a magnetic material body with a high cue point (such as an amorphous magnetic alloy thin plate) is provided in the iron core, and the magnetic material body generates heat due to loss like the amorphous magnetic alloy thin plate by high frequency excitation. I try to let them do it. The saturation magnetic flux density of magnetic materials also decreases as the temperature rises, but because the Curie point is high, at an annealing temperature of about 400°C, there is no large decrease in saturation magnetic flux density as with amorphous magnetic alloy thin sheets, and high saturation magnetic flux density can be achieved. Can be retained. In other words, the magnetic material body compensates for the decrease in saturation magnetic flux density (reduction in loss generation) of the amorphous magnetic alloy thin plate, and the heat generated by the magnetic material body causes the υ amorphous magnetic alloy thin plate to be annealed at a temperature of 400°C. It can be heated up to. Therefore, there is no need to increase the current value or frequency of the alternating current flowing through the excitation coil, and it is possible to suppress the amount of power consumed by high-frequency excitation.

Next, the effects described above will be explained using specific examples. For example, the dimensions of each part of the wound core are a": 20 cm according to Figure 2,
If b = 10 cm, c = 5 crn, and d = 10 cm, the weight of the wound core will be approximately 53 kg. The loss required to raise the temperature of the wound core to 400℃ is 25
W/kli' X 53kg= 1325 Watt
It becomes s.

As a magnetic material, G-11 class grain-oriented silicon steel plate was used in an amount of 5% by weight based on the total weight of the core (53Y x 0.05 = 2.
65 kg) are appropriately distributed and provided on the wound core. FIG. 5 shows the iron loss characteristics of a grain-oriented silicon steel sheet of G-11 class. According to this diagram, if the magnetic flux density of the silicon steel plate is 5000 Gauss at the frequency of the excitation alternating current, the iron loss will be 200 W/yu. In this case, the loss generated by the silicon steel plate is 20 Q W/kl? X 2.65y
=s 30Wat4s. In addition, when the magnetic flux density is 5000 Gauss, the amorphous magnetic alloy material METGLAS 26
The iron loss of 05 S 2 is 18W/9. In this case, the generated loss of METGLAS2605S2 is 18 W/k
ll X53kfl=950Watts. Therefore, the generated loss of grain-oriented silicon steel plate 530 Watts and M
ETGLAS2605S2 generated loss 950 Watt
In total, TGLAS2605S2 was annealed at a temperature of 40
By raising the temperature to 0°C, the necessary loss can be generated with less power.

Here, the amount of magnetic material provided in the iron core will be explained. If the amount (ratio) of the magnetic material to the total weight of the iron core is increased, the generated loss will naturally increase when the iron core is excited at high frequency, making it possible to perform annealing in a lower frequency and magnetic flux density region.

However, when the iron core is shielded by a transformer coil and used in the normal commercial frequency range, the loss generated by the μ iron core increases, and the excellent magnetic properties inherent to the amorphous magnetic alloy thin plate are impaired. Table 1 shows the changes in the no-load loss of the core at commercial frequencies when the amount of grain-oriented silicon steel plates (magnetic material) provided in the core made of amorphous magnetic alloy thin plates is changed. It is something that

Table 1 Based on this table, grain-oriented silicon steel sheets are installed in the iron core in order to avoid losing the low no-load loss characteristics that are a feature of the amorphous magnetic alloy thin sheets that make up the iron core. The ratio of (magnetic material) to the total weight of the iron core is 2 to 10
It can be said that the weight % is appropriate.

FIGS. 6 and 7 each show other embodiments. In FIG. 6, instead of providing the magnetic material 13 all over the circumferential direction of the wound core 1, the magnetic material 13 is provided partially in the leg portion and the silicate portion of the wound core 11, respectively. The case is shown below.

FIG. 7 shows a case where the wound core 11 is divided into a plurality of unit wound cores 11k in the core width direction, and a magnetic material body 13 is provided between the opposing sides of each unit wound core 11.

Although the above-mentioned embodiment 4 has been described only for the case of a wound core, the present invention is not limited to this and can also be applied to a laminated core. FIG. 8 shows an embodiment in this case, in which magnetic material bodies 23, for example grain-oriented silicon steel plates, are placed at multiple locations at intervals in the lamination direction of a laminated core 21 in which amorphous magnetic alloy thin plates 22 are laminated. This shows the case where they are interposed.

〔Effect of the invention〕

As explained above, according to the method of manufacturing the iron core of the present invention,
Since an iron core made of an amorphous magnetic alloy thin plate can be annealed in a short time by raising the temperature with a uniform temperature distribution, an iron core with excellent magnetic properties can be obtained. In addition, it is possible to reduce power consumption for annealing the iron core, reduce the size of power supply equipment, and improve economic efficiency.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the manufacturing method of the present invention, Fig. 2 is a perspective view showing a wound core in the same embodiment, and Fig. 3 is a line showing iron loss characteristics of an amorphous magnetic alloy thin plate. Figure 4 is a diagram showing the relationship between the saturation magnetic flux density and temperature of an amorphous magnetic alloy thin plate, Figure 5 is a diagram showing the iron loss characteristics of a silicon steel plate, and Figure 6 is a diagram showing the relationship between saturation magnetic flux density and temperature of an amorphous magnetic alloy thin plate.
Figures 8 to 8 are perspective views of the core showing other embodiments that are different from each other, Figure WC9 is a diagram showing the annealing characteristics of an amorphous magnetic alloy thin plate, and Figure -1O is an explanation showing the conventional method of annealing the core. Figure 11 shows the temperature rise in each part of the core when annealed by the conventional method. 11...Wound core, 12...Amorphous magnetic alloy thin plate, 13...Magnetic material body, 14...Excitation Coil, 15... Selector switch, 16... AC power supply,
17... DC power supply, 21... Laminated iron core, 22...
Amorphous magnetic alloy thin plate, 23...Magnetic material body. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Kokuzu Togu L (Nasra) Figure 4 hn Song Dynasty? T-sura Figure 6 J Figure 7 Figure 8 Figure 9 Figure 10

Claims (3)

[Claims] (1) A magnetic material body having a higher Curie point than the amorphous magnetic alloy thin plate is placed between the layers of the iron core made of the amorphous magnetic alloy thin plate, and an alternating current is passed through the coil wound around the iron core. A method for manufacturing an iron core, characterized in that the iron core is excited and annealing is performed by causing the iron core itself to generate heat due to loss generated in the iron core due to the excitation. (2) The method for manufacturing an iron core according to claim 1, wherein the iron core is provided with a magnetic material in an amount of 2 to 10% by weight based on the total weight of the iron core. (3) The method for manufacturing an iron core according to claim 1, wherein the magnetic material is a grain-oriented silicon steel plate.