JPH0670930B2 - Method of manufacturing split induction porcelain - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a split-type induction electromagnetic device such as a choke or a transformer in which a core is split into a plurality of parts.

[Conventional technology]

Conventionally, as a high frequency choke or a transformer, there is a split type in which a core made of a soft magnetic material is divided into a plurality of pieces to facilitate winding work around the core.

However, in such a split-type core, air gaps are unavoidable due to the presence of minute irregularities and cracks on the split surface of the core, which reduces the magnetic permeability of the entire core.

For example, even if the dividing surface 54 is polished with 30μ diamond particles, the relative permeability of the undivided core is 10,000.
About 50% decrease to about 5,000. for that reason,
In order to obtain the same inductance, it is necessary to increase the number of turns of the winding 52 in FIG. 8 by about 1.4 times as compared with the undivided core. Therefore, the electric resistance and the distributed capacitance due to the winding 52 increase, and as a result, the characteristics of the high frequency choke deteriorate.

Therefore, the applicant of the present application has previously proposed a method of recovering the magnetic permeability of the core by inserting a magnetic fluid between both split surfaces of the split core (Japanese Patent Application No. 2-13355).

[Problems to be Solved by the Invention]

However, even with such a method, the recovery of the magnetic permeability of the core can be achieved by reducing the relative magnetic permeability of the undivided core to 10,000.
In the case of the degree, it is 75 to 80%, which is not yet sufficient.

The present invention has been made in view of the above problems. Therefore, in a split-type induction ceramic, the characteristics can be improved by sufficiently recovering the magnetic permeability of the core without significantly increasing the cost. It aims at providing the manufacturing method of.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention inserts a filling material containing a magnetic fluid between both split surfaces of a split core, and applies the magnetic field in a direction intersecting with the split surface, Is solidifying.

[Action]

According to the present invention, since the soft magnetic material particles are interposed between both of the divided surfaces, the soft magnetic material particles enter into minute irregularities and cracks between the divided surfaces to fill the air gap.
Here, the fine particles of the soft magnetic material are usually 1 μm or less, for example, 100 Å to 400 Å, and since the particle size is extremely small,
Do not widen the air gap. Therefore, the magnetic permeability of the core is improved.

Moreover, since the filling material is solidified in a state where a magnetic field is applied in the direction intersecting the dividing plane, the filling material expands outward due to the magnetic field, which widens the magnetic path of the filling material, resulting in a magnetic permeability. Is further improved.

〔Example〕

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

1 and 2 show an example of a high frequency choke manufactured by the method of the present invention.

In FIG. 1, a high frequency choke core 50 is composed of two cores 51 and 51 (hereinafter referred to as split cores), and windings 52 and 52 are wound around these split cores 51 and 51. There is. The windings 52, 52 are balanced-wound so that the magnetic fields generated by the current from the input source are in opposite directions.

The split surface 54 of the E-shaped split cores 51, 51 has a particle size of 3
Finished by polishing with 0μ grain. Second
As shown in the enlarged view of the figure, between the split cores 51, 51 (hereinafter, referred to as “gap”) G, particles of a soft magnetic material are provided.
A magnetic fluid 12 made by dispersing 10 in a dispersant 14 is a filler.
It is inserted as 12. Furthermore, the split cores of FIG.
The 51 (51) is fixed to each other by applying an adhesive (fixing means) 11 made of an epoxy resin or a silicon resin to several places on the outer periphery of the divided surface 54 on the side surface 55.

Next, an embodiment of the manufacturing method of the present invention will be described.

First, the split surface 54 of both split cores 51, 51 shown in FIG.
After being finished with 30 μ of abrasive grains, the winding wire 52 is wound around the split core 51. On the other hand, the filler 12 made of the magnetic fluid shown in FIG. 2 manufactured by the coprecipitation method is applied to the divided surfaces 54, 54. After this coating, as shown in FIG. 3 (B), each split core 51, 51
A magnetic field B is applied in a direction intersecting with the split surfaces 54, 54 by causing a direct current to flow through the windings 52, 52 in a state of being lightly pressed. As a result, the filler 12 receives the magnetic force and enters the cracks C and the unevenness H in the gap G of FIG.
As shown in FIG. 3 (C), the filling material 12 has a shape that bulges outward along the line of magnetic force B1. In this state, the filler 12 is dried and solidified.

Subsequently, as shown in FIG. 3D, the split cores 51, 51 are bonded to each other with the adhesive 11 at several points to obtain a high frequency choke.

Here, the magnetic fluid 12 means the fine particles 10 of the soft magnetic material shown in FIG.
It is a liquid that is dispersed in a high concentration inside and that behaves as a magnetic fluid. As the magnetic fluid 12, for example, a manganese-zinc-based ferrite magnetic fluid containing 10 to 25% by volume of the soft magnetic particles 10 can be used. Further, as the dispersant 14 for the magnetic fluid 12, water or the like can be used in addition to petroleum-based resin or paraffin. Furthermore, the particle size of the soft magnetic particles 10 is usually 1
It is preferably μ or less, for example, about 100 Å to 400 Å.

In the above structure, the soft magnetic particles 10 in the filler 12 made of the magnetic fluid shown in FIG.
Or into the unevenness H to fill the gap G. Therefore, the magnetic permeability in the portion of the gap G is remarkably improved, and since the particle size of the fine particles 10 is small, the gap G does not expand due to the presence of the fine particles. Further, the magnetic field B causes the filling material 12 to bulge outward as shown in FIG. 3 (C), so that the magnetic path in the filling material 12 expands.

As a result, the magnetic permeability of the entire core 50 in FIG. 1 is restored to a value close to the magnetic permeability of the undivided core. In the case of a core whose relative magnetic permeability of the undivided core is about 10,000, when the filler is solidified without applying the magnetic field B, no outward bulge of the filler 12 is formed. While the magnetic susceptibility only recovered to about 75% to 80%, the method of the present invention recovered to about 90%.

In this way, the magnetic permeability of the entire core 50 is restored, so the winding
The number of turns of 52 can be reduced as compared with the conventional split type high frequency choke. Therefore, since the electric resistance and the distributed capacitance are reduced, the characteristics of the high frequency choke are improved.

Further, since it is not necessary to finish the dividing surface 54 with high accuracy to the submicron level, there is no fear of causing a significant increase in cost. Even if the divided surface 54 was actually mirror-finished to 0.5 to 3 μ, there was no difference in the recovery rate of the magnetic permeability as compared with the case of 30 μ of the above-mentioned embodiment.

In this embodiment, the two split cores 51, 51 are attached to the adhesive 1
Although they are adhered to each other by 1, they are not necessarily adhered. When the split cores 51, 51 are not adhered to each other, the magnetic permeability is slightly reduced when the core 50 is subjected to an impact force. This is because the two split cores 51, 51 are slightly displaced in the X direction or the Y direction of FIG. 1 due to the impact force applied to the core 50, so that the state (shape) of the gap G (FIG. 2) is changed. )
It is presumed that this is due to the subtle changes in.

On the other hand, as in the embodiment of FIG. 1, both split cores 51, 5
When 1 is fixed to each other, even if an impact force is applied, both split cores 51, 51 are not likely to be displaced from each other.
Permeability does not decrease. Therefore, when used in an environment where it is likely to receive an impact force, it is preferable to fix both split cores 51, 51 to each other by a fixing means (adhesive 11).

In addition, as another method of applying the magnetic field B to the filler 12, the fourth method
As shown in the figure, the magnets 21 and 22 may be arranged above and below the core 50. As shown in FIG. 5, the magnet 22 is provided on one side and the magnetic path made of a soft magnetic material such as iron on the other side. The forming members 23 may be arranged respectively.

As a method of inserting the magnetic fluid 12 shown in FIG. 2 into the gap G, there is a method of utilizing the capillary phenomenon described below, in addition to the above-mentioned method of coating. This method will be described with reference to FIG.

After the filling material 12 made of magnetic fluid is filled in the dropper S, the tip end opening S1 of the dropper S is pressed against the outer periphery of the dividing surface 54, and the magnetic fluid 12 in the dropper S becomes the gap G (first (Fig. 2)

At this time, if the magnetic field B is applied, the filler 12 can more quickly enter.

FIG. 7 shows a second embodiment of the present invention.

In FIG. 7, a filling material 12 made of a magnetic fluid is interposed between the divided surfaces 54, 54, and is dried and solidified under a magnetic field B applied thereto. The outer periphery of the core 50 on the dividing surface 54 is covered with a covering material 15 made of, for example, epoxy resin or silicon resin.

As a result, the outer peripheral portion of the filler 12 that bulges outward is protected, and there is no risk of the filler 12 chipping off by hitting surrounding objects.

8 and 9 show a third embodiment of the present invention.

Between the dividing surfaces 54, 54 of FIG. 8, as shown in FIG.
An adhesive 17 made of a magnetic fluid in which fine particles 10 of a soft magnetic material are mixed in 6 is inserted and solidified as a filler. Therefore, the split cores 51, 51 are bonded to each other by the cured resin 16.

As an example of the method of interposing and hardening the filler 17 made of an adhesive in the gap G, first, the soft magnetic fine particles 10 are dispersed in the monomer of the thermosetting resin 16 as a dispersant. The magnetic fluid (filler 17) thus formed is injected into the gap G. Then, by the same method as shown in FIGS. 3B to 3D, heating is performed while applying the magnetic field B to solidify the resin 16 by the polymerization reaction.

In this embodiment, the split cores 51, 51 are mechanically and firmly joined by the resin 16 in which the filler 17 made of an adhesive material is solidified. Therefore, even if an impact force is applied to the core 50, the two split cores 51, 51 are not displaced with respect to each other, and therefore the magnetic permeability is not likely to decrease with time due to the displacement.

By the way, in each of the above examples, the soft magnetic particles 10
As the manganese-zinc-based ferrite powder, a ferrite containing manganese, iron, nickel, copper, magnesium or the like can be used. In particular, by using ferrite having a higher magnetic permeability than the soft magnetic material forming the split cores 51, 51, the magnetic permeability of the entire core 50 can be made closer to the magnetic permeability of the undivided core.

The soft magnetic particles 10 may be obtained by a chemical synthesis method such as the coprecipitation method, or fine particles of sintered ferrite may be used.

Further, in each of the above-described embodiments, the winding 52 is balancedly wound as shown in FIG. 1, but the number of the winding 52 may be one.

Further, although the above embodiments have been described with respect to the high frequency choke, the present invention can be applied to a transformer.

Further, in each of the above-described embodiments, each split core 51 has been described as having an E shape, but the present invention can be applied even if the split core 51 has a U shape as shown in FIG.

〔The invention's effect〕

As described above, according to the present invention, the filler containing the magnetic fluid is introduced into the irregularities and cracks of the gap generated on the split surface of the split core to improve the magnetic permeability of the core.
The magnetic field expands the filler outward to expand the magnetic path, further improving the magnetic permeability, and thus improving the characteristics of the induction ceramic provided with the split core.

Further, since it is not necessary to finish the divided surface with high precision, there is no fear of significantly increasing the cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a high frequency choke manufactured by the method of the present invention, FIG. 2 is an enlarged sectional view of a gap of the choke, and FIG. 3 is a manufacturing process drawing showing a first embodiment of the present invention. 4 and 5 are modification examples of a method of applying a magnetic field, FIG. 6 is a perspective view showing a modification example of a method of interposing a filler on a dividing surface, and FIG. 7 is a high frequency wave showing a second embodiment. FIG. 8 is a perspective view of a choke, FIG. 8 is a perspective view of a high frequency choke showing a third embodiment, and FIG. 9 is an enlarged sectional view of a gap in FIG.
FIG. 10 is a front view showing another high frequency choke to which the present invention can be applied. 10: Soft magnetic particles, 11: Fixing means (adhesive),
12 …… filling material, 15 …… sealing material, 16 …… resin, 17 …… filling material (adhesive), 50 …… core, 51 …… split core, 52 ……
Winding, 54 ... split plane, G ... gap (between split planes).

Claims (1)

[Claims] 1. A method for manufacturing a split-type induction ceramic in which a core around which a winding is wound is divided into a plurality of parts, wherein a filler containing magnetic fluid is inserted between both split surfaces of the split core.
A method of manufacturing a split induction porcelain, characterized in that the filling material is solidified in a state in which a magnetic field is applied in a direction intersecting with the split surface.