JPH04356906A - Composite magnetic core and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a composite magnetic core possessing magnetic permeability characteristics having non-linear characteristics to a DC superposition magnetic field by a method wherein specified amorphous alloy ribbons are combined with each other to obtain a core main body and thereafter, the main body is heat-treated to form the composite magnetic core. CONSTITUTION:A first ribbon 1a is used as a Co amorphous magnetic alloy ribbon and a second ribbon 1b is used as an Fe amorphous magnetic alloy ribbon. The second ribbon 1b is fed out from a second roll 3b and a Capton tape piece 10 is adhered on the tip of the ribbon 1b so that an adhesive surface is positioned on the tip. The ribbon 1b is wound on the periphery of a wound core 6 and the wound core is rotated only a little over one rotation and is fixed annularly. Then, the starting end of the ribbon 1a from a first roll 3a is inserted in the core 6 while the ribbon 1b is wound on the core 6 and after the ribbons 1a and 1b are alternately wound on the core 6 and a lap winding part is formed, the first ribbon is cut to wind the second ribbon 1b only and a magnetic core main body 12 is obtained. This main body is heat-treated to obtain a composite magnetic core. Thereby, a magnetic core possessing L type characteristics, wherein the magnetic permeability scarcely varies in a current range between some point and a core saturating point, can be formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic core having a property that magnetic permeability is non-linear with respect to a DC superimposed magnetic field, and a method for manufacturing the same.

0002

2. Description of the Related Art In a normal smooth choke, the permeability of the magnetic core material is nearly constant from a low magnetic field to a magnetic field where the magnetic core is saturated, and the change in inductance is small even when the current flowing through the coil becomes small.

For this reason, when used as a smoothing choke for a switching power supply, there has been a problem in that output voltage fluctuates when the load current is small. For this reason, the problem has been solved by adding a circuit to suppress fluctuations in the output voltage.

0004

[Problems to be Solved by the Invention] However, with the above technology, there are problems such as an increase in cost due to the increase in the number of parts and an increase in the size of the power supply due to the increase in the number of parts. A choke using a core having an L-shaped nonlinear characteristic in which the change in magnetic permeability is small until the magnetic core is saturated from a certain current level is required.

In order to solve this problem, chokes of the half-gap type, in which a magnetic material with high magnetic permeability is placed near the gap of the core, or where the magnetic path cross section of the magnetic material with high magnetic permeability is partially cut, have been developed. A magnetic core has been proposed.

However, in these methods, since there is a gap in the magnetic core, magnetic flux leaks from the gap.
When used in electronic equipment, etc., problems such as noise may occur, which is not very preferable.

[0007] Furthermore, when there is a load fluctuation at an audio frequency,
Magnetostriction of the magnetic material causes expansion and contraction of the magnetic core, and when there is a gap in the magnetic path, the sound generation is particularly noticeable at the gap, so it could not be used in applications where magnetic core noise would be a problem.

In order to solve the above problem, a non-gap type choke with non-linear characteristics was created by combining cores heat-treated at different temperatures into a single magnetic core using Fe-based amorphous alloys. However, the manufacturing process is complicated by the need for two heat treatment processes and the additional process of combining two cores into one magnetic core, resulting in high manufacturing costs. There was a problem.

The present invention has been made in view of the above-mentioned problems, and its object is to efficiently and at low cost supply a magnetic core whose magnetic permeability characteristics are non-linear with respect to a DC superimposed magnetic field. It is in.

0010

[Means for Solving the Problems] The first gist of the present invention is as follows:
This is a composite magnetic core in which a magnetic core body is obtained by combining an Fe-based amorphous magnetic alloy ribbon and a Co-based amorphous magnetic alloy ribbon, and then this magnetic core body is heat-treated.

The second gist is a method for manufacturing a composite magnetic core, which is obtained by combining an Fe-based amorphous magnetic alloy ribbon and a Co-based amorphous magnetic alloy ribbon to obtain a magnetic core body, and then heat-treating the magnetic core body. It is.

The third point is that when manufacturing a composite magnetic core,
The first ribbon is an Fe-based amorphous magnetic alloy ribbon or a Co
After winding the first ribbon, the second ribbon is a Co-based amorphous magnetic alloy ribbon or a Fe-based amorphous magnetic alloy ribbon. After that, the magnetic core body is obtained by winding the magnetic core body from above, and then the magnetic core body is heat-treated.

The fourth aspect is that the first ribbon is an Fe-based amorphous magnetic alloy ribbon or a Co-based amorphous magnetic alloy ribbon, and the second ribbon is a Co-based amorphous magnetic alloy ribbon or a Fe-based non-crystalline magnetic alloy ribbon. As a crystalline magnetic alloy ribbon, the second ribbon is inserted in the middle of winding the first ribbon to obtain a magnetic core body having a heavily wound portion in which the first and second ribbons are alternately wound in layers. After that, the core body is heat treated.

A fifth aspect is that in the first, second, third or fourth aspect, the heat treatment temperature range is Tx-20°C to Tx, where Tx is the crystallization temperature of the Fe-based amorphous alloy.
The temperature should be within the range of -100°C.

[0015]

[Operation] The Fe-based amorphous magnetic alloy ribbon and the Co-based amorphous magnetic alloy ribbon constituting the composite magnetic core may be processed into slit shapes, combined with each other, and wound. Note that the ends of these wound bodies may be fixed with Kapton tape or the like.

[0016] The Fe-based amorphous alloy (Fe
Examples of Fe-based amorphous alloys (metals) include Fe-based amorphous alloys (metals) in which the content of Fe in the alloy is 50 atomic % or more;
B, Fe-B-C, Fe-B-Si, Fe-B-Si-
Examples include Fe-based materials such as C, Fe-B-Si-Cr, and Fe-Ni-Mo-B.

Among these, a particularly preferable Fe-based amorphous alloy is FexSiyBzMw. Here x=50~85, y=0~15, z=5~25 (x, y
, z all represent atomic %). Also, M is Ni, Nb, Ta, Mo, W, Zr, Cu, Cr, Mn
, C, Al, P, etc., or a combination of two or more of them, with w=0 to 5 atomic %.

[0018] Also, as the Co-based amorphous alloy, Coa
-Feb-Mc-Sid-Be can be exemplified. here,
a=60-90, b=0-10, d=0-15, e=5
~25 (all represent atomic %), M is N
i, Nb, Ta, Mo, W, Zr, Cu, Cr, Mn,
A metal consisting of one or a combination of two or more of C, Al, P, etc., and c=0 to 10 (atomic %) can be exemplified.

[0019] Furthermore, a humid atmosphere may be used as the treatment condition during the heat treatment. In this case, it is desirable to heat-treat the magnetic core body in a humid atmosphere with a unit water vapor amount of 3 to 600 g/m 3 , particularly preferably 20 to 200 g/m 3 at 25°C.

[0020] The heat treatment temperature is Tx-20°C to Tx-10°C.
Preferably, the temperature is 0° C. (where Tx is the crystallization temperature of the Fe-based amorphous alloy).

[0021] Here, the crystallization temperature (Tx) is
This is the apex temperature of the exothermic peak of the first crystallization obtained when measured using a differential scanning calorimeter (differential scanning calorimeter) at a temperature increase rate of 10° C./min.

The heat treatment atmosphere may be the same as the atmosphere, but preferably an inert atmosphere such as a nitrogen atmosphere is used to prevent peeling of the Kapton tape used to fasten the ends of the amorphous ribbon. It can also be prevented.

Further, according to the present invention, by inserting magnetic ribbons having different crystallization temperatures into the winding of the first ribbon, the end of the first ribbon can be connected with a joining means such as Kapton tape or welding. There is no need to use a winding device, and the magnetic core can be manufactured using a simple winding device.

[0024]

EXAMPLES Examples of the present invention will be described below based on experimental examples and comparative examples.

FIG. 1 is a schematic diagram showing a magnetic ribbon winding device for obtaining a magnetic core in one embodiment of the present invention.

In the figure, a first roll 3a for supplying a first ribbon 1a and a second roll 3b for supplying a second ribbon 1b are arranged, and a ribbon thickness measuring device 11, a tension detection roll 4 and a second roll 3b are arranged, respectively. Cutter 5a, 5
It has a structure in which the ribbon is supplied to the winding core 6 via the ribbon feeding device 9 and the ribbon feeding device 9.

In addition, in the figure, the tension detector 4
, the ribbon thickness measuring device 11, and the ribbon feeding device 9 are each arranged only in one ribbon supply system for simplicity of drawing, but they are provided in common to both supply systems.

Experimental examples and comparative examples for obtaining composite magnetic cores using the winding device shown in FIG. 1 described above will be described below. (Experiment Example 1) - First ribbon (1a) Composition: (atomic %): Co67.7Fe3.8Ni1.5
Si13.7B13.4 Thickness: 20 μm Width: 10 mm ・Second ribbon (1b) Composition: (atomic %): Fe80Si8B12 Crystallization first peak temperature: 510.5°C Thickness: 21 μm Width: 10 mm First, second roll 3b The second ribbon 1b is unrolled, and a Kapton tape piece 10 is adhered to the tip thereof so that the adhesive surface is located outside the winding core 6.

[0029] Then, a second ribbon 1b is placed around the winding core 6.
, and rotate the winding core 6 by a little more than one rotation in the direction of the arrow. This fixes the second ribbon 1b in an annular shape.

Next, the starting end of the first ribbon 1a from the first roll 3a is inserted into the middle of the winding of the second ribbon 1b,
After the second ribbon 1b and the first ribbon 1a are alternately wound by rotation of the winding core to form a heavily wound portion (1b+1a), the first ribbon 1a is cut to a predetermined length by a cutter 5b. , winding only the second ribbon 1b,
A magnetic core body 12 shown in FIG. 3 was obtained.

[0031] At this time, the first ribbon 1a and the second ribbon 1
The weight ratio with b was 1:2 (first ribbon 1a: second ribbon 1b).

The outer diameter of the magnetic core body 12 was 25 mm, and the inner diameter was 15 mm. This magnetic core body 12 was heat-treated in an electric furnace at 450° C. for 2 hours in a N2 atmosphere to obtain a composite magnetic core.

FIG. 5 shows the relationship between the magnetic permeability of the composite magnetic core obtained in this way and the DC superimposed magnetic field. (Experiment Example 2) ・First ribbon (1a) Composition: (atomic %): Fe80Si8B12 Crystallization first peak temperature: 510.5°C Thickness: 21 μm Width: 10 mm ・Second ribbon (1b) Composition: (atomic %) ):Co67.7Fe3.8Ni1.5
Si13.7B13.4 Thickness: 20 μm Width: 10 mm Using the winding device shown in FIG.
After winding a predetermined number of times, the starting end of the first ribbon 1a is inserted into the winding end of the second ribbon 1b, and the first ribbon 1a and the second ribbon 1b are stacked in two by rotation of the winding core 6. Wind the wire a specified number of times in this condition.

Next, the second ribbon 1b is cut by the cutter 5b.
After that, only the first ribbon 1a is wound,
A magnetic core body 13 shown in FIG. 4 was obtained. At this time, the amount of winding of both ribbons is controlled so that the weight ratio of the first ribbon 1a and the second ribbon 1b is 3:2 (first ribbon 1a:second ribbon 1b).

The magnetic core body 13 thus obtained had an outer diameter of 25 mm and an inner diameter of 15 mm. This magnetic core body 13 was heated for 452 hours in an N2 atmosphere in an electric furnace.
A composite magnetic core was obtained by heat treatment at ℃ for 2 hours.

FIG. 5 shows the relationship between the magnetic permeability of the composite magnetic core obtained in this manner and the DC superimposed magnetic field. (Comparative example) - Ribbon composition: (atomic %): Fe80Si8B12 First crystallization peak temperature: 510.5°C Thickness: 21 μm Width: 10 mm Using the winding device shown in Figure 1, a ribbon with an outer diameter of 25 mm and an inner diameter of 15 mm was A magnetic core body was obtained. This magnetic core body was heat-treated at 450° C. for 2 hours in an N2 atmosphere in an electric furnace to obtain a composite magnetic core.

FIG. 5 shows the relationship between the magnetic permeability of the composite magnetic core obtained in this way and the DC superimposed magnetic field.

Comparing Experimental Examples 1 and 2 with the comparative example above, in this example, the inductance is large when the current flowing through the coil is small, and the permeability does not change from a certain current level until the magnetic core is saturated. It has become clear that a magnetic core with small L-shaped characteristics can be obtained.

[0039]

According to the present invention, a non-gap type choke coil having L-shaped nonlinear characteristics can be obtained efficiently and at low cost through a simple manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing a magnetic coil winding device for obtaining a magnetic core in an embodiment of the present invention.

[Fig. 2] A conceptual diagram showing the winding state of the magnetic ribbon in the example.

[Fig. 3] Explanatory diagram showing the structure of the magnetic core body in Example (Experiment Example 1)

[Fig. 4] Explanatory diagram showing the structure of the magnetic core body in Example (Experiment Example 2)

FIG. 5 is a graph diagram showing changes in magnetic permeability in response to a DC superimposed magnetic field of a magnetic core in Experimental Example 1, Experimental Example 2, and Comparative Example in the embodiment of the present invention.

[Explanation of symbols]

1a: 1st ribbon 1b...Second ribbon 2.Magnetic core body 3a... 1st roll 3b...Second roll 4...Tension detection roll 5a, 5b...Cutter 6. Rolling core 9. Ribbon feeding device 10... Tape piece (Kapton tape) 11. Ribbon thickness measuring device 12, 13...Magnetic core body

Claims (5)

[Claims] 1. A composite magnetic core obtained by combining an Fe-based amorphous magnetic alloy ribbon and a Co-based amorphous magnetic alloy ribbon to obtain a magnetic core body, and then heat-treating the magnetic core body. 2. A method for manufacturing a composite magnetic core, which comprises combining an Fe-based amorphous magnetic alloy ribbon and a Co-based amorphous magnetic alloy ribbon to obtain a magnetic core body, and then heat-treating the magnetic core body. 3. The first ribbon is an Fe-based amorphous magnetic alloy ribbon or a Co-based amorphous magnetic alloy ribbon, and the second ribbon is a Co-based amorphous magnetic alloy ribbon or a Fe-based amorphous magnetic alloy. A composite magnetic core characterized in that after winding of the first ribbon as a ribbon is completed, a second ribbon is continued to be wound thereon to obtain a magnetic core body, and then this magnetic core body is heat-treated. Production method. 4. The first ribbon is an Fe-based amorphous magnetic alloy ribbon or a Co-based amorphous magnetic alloy ribbon, and the second ribbon is a Co-based amorphous magnetic alloy ribbon or a Fe-based amorphous magnetic alloy. As a ribbon, the second ribbon is inserted in the middle of winding the first ribbon to obtain a magnetic core body having a heavily wound portion in which the first and second ribbons are alternately wound. A method for manufacturing a composite magnetic core, characterized by heat-treating the magnetic core body. [Claim 5] In claim 1, 2, 3 or 4,
A method for manufacturing a composite magnetic core, characterized in that the heat treatment temperature range is from Tx-20°C to Tx-100°C, where Tx is the crystallization temperature of the Fe-based amorphous alloy.