JPH043906A - Manufacture of split-type induction electromagnetic device - Google Patents

Abstract

PURPOSE:To sufficiently recover the permeability of a core and to improve the characteristics by a method wherein a filling material including a magnetic fluid is interposed between both split faces of divided cores and this filling material is set up while applying a magnetic field in a direction crossing the split faces. CONSTITUTION:After polishing split faces 54, 54 of both split cores 51, 51 by abrasive grains of 30mu, a windings 52 is wound around the split core 51. Meanwhile, a filling material 12 consisting of a magnetic fluid manufactured by a co-precipitation method is spread over split faces 54, 54. After coating of this filling material 12, a direct current is allowed to flow in the windings 52, 52 while the split cores 51, 51 are in contact with each other with a slight pressure. Then, a magnetic field B is applied in a direction which crosses the split faces 54, 54. At a result, the filling material 12 can get into all cracks or recesses in a gap caused by a magnetic force, meanwhile the filing material 12 swells outward along a line of magnetic force B1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application 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 the core is divided into a plurality of parts.

[Conventional technology]

Conventionally, there are split-type high-frequency chokes and transformers in which a core made of a soft magnetic material is divided into a plurality of parts to facilitate winding of windings around the core.

However, in such a split-type core, minute irregularities and cracks exist on the split surface of the core, so it is inevitable that an air gap will be created, and as a result, the magnetic permeability of the entire core decreases.

For example, even if the dividing surface 54 is polished with 30μ diamond particles, the relative permeability of the undivided core is 1.
The value of about 0.000 decreases to about 5.000, which is 50%. Therefore, 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 that of the undivided core. Therefore, the electrical resistance and distributed capacitance due to the winding 52 increase, resulting in a problem that the characteristics of the high frequency choke deteriorate.

Therefore, the applicant previously proposed a method of restoring the magnetic permeability of the core by inserting a magnetic fluid between the two divided surfaces of the divided core (Japanese Patent Application No. 13355/1999).
.

[Problem to be solved by the invention]

However, even with this method, the recovery of the magnetic permeability of the core is limited to the relative magnetic permeability of the undivided core or 10,
000, it is 75 to 80%, which is still not sufficient.

This invention was made in view of the above-mentioned problem, and it is possible to improve the characteristics of a split-type induction electromagnetic device by sufficiently recovering the magnetic permeability of the core without incurring significant cost or loss. The purpose of the present invention is to provide a method for manufacturing induction electromagnetic ceramics.

[Means to solve the problem]

In order to achieve the above object, the present invention interposes a filler containing magnetic fluid between both dividing surfaces of a split core, and applies a magnetic field in a direction intersecting the dividing surfaces. The filling material is solidified.

[Effect]

According to this invention, since the soft magnetic particles are inserted between the two dividing surfaces, the soft magnetic particles enter into minute irregularities and cracks between the dividing surfaces and fill the air gap.

Here, the fine particles of the soft magnetic material are usually 1 micrometer or less, for example, 100 to 400 particles, and are extremely small in size, so they do not widen the air gap. Therefore, the magnetic permeability of the core is improved.

Furthermore, since the filler is solidified while a magnetic field is applied in a direction that intersects the dividing plane, the magnetic field causes the filler to bulge outward, which widens the magnetic path of the filler and, as a result, increases the magnetic permeability. further improves.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

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

In FIG. 1, the core 50 of the high frequency choke consists of two divided cores (hereinafter referred to as divided cores) 5151, and these divided cores 51. A winding 52.52 is wound around the fence. The windings 52, 52 are balanced so that the magnetic fields generated by the current from the input source are in opposite directions.

The divided surfaces 54 of the E-shaped divided cores 51.51 are polished and finished with abrasive grains having a particle size of 30 μm. As shown in the enlarged view of Fig. 2, both split cores 51.5
1 (hereinafter referred to as "gear knob") G, a magnetic fluid 12 made of soft magnetic fine particles 10 dispersed in a dispersant 14 is inserted as a filler 12. Further, both split cores 51.51 in FIG. 1 are fixed to each other by applying an adhesive (fixing means) 11 made of Evokin resin or silicone resin to several places on the outer periphery of the split surface 54 on the side surface 55. ing.

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

First, after finishing the split surfaces 54 of both split cores 51 and 51 shown in FIG. 3(A) with 30μ abrasive grains, the winding 52 is wound around the split cores 51. On the other hand, the second
The filling material 12 made of magnetic fluid shown in the figure is placed on each dividing surface 54.5.
Apply to 4. After this application, as shown in FIG. 3(B), by applying a direct current to the windings 52, 52 with each split core 51, 51 lightly pressed together, the split surface 54.
A magnetic field B is applied in a direction intersecting with 54. As a result, the filler 12 receives magnetic force, causing the crack C in the gear knob G in FIG.
While the filling material 12 penetrates into the irregularities H, the filling material 12 has a shape that bulges outward along the lines of magnetic force B1, as shown in FIG. 3(C).

In this state, the filler 12 is dried and solidified.

Subsequently, as shown in FIG. 3(D), both split cores 51 and 51 are bonded to each other with adhesive 11 at several locations to obtain a high frequency choke.

Here, the magnetic fluid 12 is one in which fine particles 10 of the soft magnetic material shown in FIG. It refers to something that behaves like a fluid.

As the magnetic fluid 12, for example, soft magnetic particles I
A mankanzinc-based ferrite magnetic fluid containing O in an amount of 10 to 25% by volume may be used. Further, as the dispersant 14 of the magnetic fluid 12, water or the like can be used in addition to petroleum-based Lessino or paraffin. Furthermore, the particle size of the soft magnetic fine particles 10 is usually 1 μm or less, for example, preferably about 100 to 400 particles.

In the above configuration, the soft magnetic particles 10 in the filler 12 made of magnetic fluid shown in FIG. Therefore, the magnetic permeability of the gap G portion is significantly improved, and since the particle size of the fine particles 1o is small, the gap G does not widen due to the presence of the fine particles. Furthermore, the magnetic field B causes the filler 12 to take on an outwardly swollen shape as shown in FIG. 3(C), so that the magnetic path in the filler 12 widens.

As a result, the magnetic permeability of the entire core 50 in FIG. 1 is restored to a value close to that of the undivided core. In the case of an undivided core with a relative magnetic permeability of 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 relative magnetic permeability was only recovered to about 75% to 80%, according to the method of the present invention, it was recovered to about 90%.

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

Furthermore, since there is no need to finish the dividing surface 54 with high precision down to submicron levels, there is no risk of a significant increase in cost. Actually, the dividing surface 54 is mirror-finished to 0.5 to 3
Even when finished to μ, there was no difference in the recovery rate of magnetic permeability compared to the case of 30 μ in the above example.

In this embodiment, the two divided cores 51.51 are bonded to each other with the adhesive 11, but it is not necessary to bond them together. If both split cores 51 and 51 are not bonded to each other, when an impact force is applied to the core 50, the magnetic permeability will decrease slightly. This occurs because the two split cores 51 and 51 are slightly displaced in the X direction or Y direction in FIG.
It is presumed that this is due to a slight change in the state (shape) of (Fig.).

On the other hand, as in the embodiment shown in FIG.
．． 51 are fixed together, even if an impact force is applied,
Since there is no risk that the two split cores 51, 51 will be displaced from each other, the magnetic permeability will not decrease. Therefore, when used in an environment where it is easy to receive impact force, both split cores 51 and 51
are preferably fixed to each other by means of fixing means (adhesive 11).

Further, as another method of applying the magnetic field B to the filler 12, as shown in FIG. 4, magnets 21 and 22 may be placed above and below the core 50, or as shown in FIG. magnet 22
and a magnetic path forming member 2 made of a soft magnetic material such as iron on the other side.
3 may be placed respectively.

As a method for inserting the magnetic fluid 12 shown in FIG. 2 into the gap G, in addition to the above-mentioned coating method, there is a method using capillary phenomenon described below. This method will be explained using FIG. 6.

After filling the filler 12 made of magnetic fluid into the syringe S, when the tip opening S1 of the syringe S is pressed against the outer periphery of the dividing surface 54, the magnetic fluid 12 in the syringe S fills the gap G (first Figure 2) Invades the inside.

At this time, if a magnetic field B is applied, the filling material 12 can penetrate more quickly.

FIG. 7 shows a second embodiment of the invention.

In FIG. 7, a filler 12 made of magnetic fluid is inserted between the two dividing surfaces 54 and 54, and is dried and solidified while a magnetic field B is applied thereto. The outer periphery of the core 50 at the dividing surface 54 is covered with a covering material 15 made of evoquin resin or silicone resin, for example.

This protects the outer periphery of the filling material 12 that bulges outward, eliminating the risk of the filling material 12 being chipped by hitting surrounding objects.

8 and 9 show a third embodiment of the invention.

Between the dividing planes 54 and 54 in Fig. 8, as shown in Fig. 9,
An adhesive 17 made of a magnetic fluid in which fine particles 10 of soft magnetic material are mixed into resin 16 is inserted and solidified as a filler. Therefore, both split cores 51.51 are made of hardened resin 1.
They are joined to each other by 6.

As described above, as an example of a method of inserting and curing the filler 17 made of an adhesive into the gap G, first, microparticles lO of soft magnetic material are added to the monomer of the thermosetting resin 16 as a dispersant.
A magnetic fluid (filling material 17) made of dispersed particles is injected into the gap G. Then, in the same manner as shown in FIGS. 3(B) to 3(D), the resin 16 is heated while applying a magnetic field B to solidify the resin 16 by a polymerization reaction.

In this embodiment, each divided core 51.51 is mechanically and firmly joined by solidified resin 16 of filler 17 made of adhesive. Therefore, even if an impact force is applied to the core 50, the two divided cores 51, 51 will not be displaced from each other, so there is no risk that the magnetic permeability will decrease over time due to positional displacement.

By the way, in each of the above examples, soft magnetic particles 1
In addition to manganese-zinc-based ferrite powder, ferrite containing manganese, iron, nickel, copper, magnesium, etc. can be used as the material. In particular, split core 51.
By using ferrite having a higher magnetic permeability than the soft magnetic material constituting the core 51, the magnetic permeability of the entire core 50 is
The magnetic permeability can be made even closer to that of an undivided core.

Further, as the soft magnetic particles 1O, in addition to those obtained by a chemical synthesis method such as the coprecipitation method described above, those obtained by pulverizing sintered ferrite can also be used.

Further, in each of the embodiments described above, the winding 52 may be balanced-wound as shown in FIG. 1, or the winding 52 may be a single winding.

Furthermore, although each of the above embodiments has been described with respect to a high frequency choke, the present invention can also be applied to a transformer.

In addition, in each of the above embodiments, each split core 51 is E-shaped, or the shape of the split core 51 is different from the first one.
As shown in Figure 0, the present invention can be applied even to a U-shape.

〔Effect of the invention〕

As explained above, according to the present invention, the filler containing the magnetic fluid enters the unevenness and cracks of the gap that occurs on the split surface of the split core, improving the magnetic permeability of the core, and further,
The magnetic field expands the filler material outward and widens the magnetic path, further improving the magnetic permeability and improving the properties of the induction ceramic with the split core.

Furthermore, since there is no need to finish the dividing surfaces with high precision, there is no risk of a significant increase in cost.

[Brief explanation 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 the gap of the choke, and Fig. 3 is a manufacturing process diagram showing the first embodiment of the invention. , FIG. 4 and FIG. 5 are a modified example of the method of applying a magnetic field, FIG. 6 is a perspective view of a modified method of inserting a filler into the dividing surface, and FIG. 7 is a high-frequency diagram showing a second embodiment. FIG. 8 is a perspective view of a high-frequency choke showing the third embodiment; FIG. 9 is an enlarged sectional view of the gap in FIG. 8;
FIG. 0 is a front view showing another high frequency choke to which the present invention can be applied. DESCRIPTION OF SYMBOLS 10... Fine particles of soft magnetic material, 11-. Fixing means (adhesive), 12... Filler, 15... Sealing material, 16.
... Resin, 17... Filler (adhesive), 50... Core, 51... Split core, 52-... Winding wire, 54...
Dividing plane, G... Gap (between dividing planes). 10: 1st temple of mold of Tokosei, Efukyi (C) Fig. 9 (D) 15: Nrupak Fig. 10

Claims (1)

[Claims] (1) In a method for manufacturing a split type induction electromagnetic device in which a core around which a winding is wound is divided into a plurality of parts, a filler containing a magnetic fluid is inserted between both split faces of the split core, and a filler containing a magnetic fluid is inserted between the split faces of the split core. A method for manufacturing a split induction electromagnetic ceramic, characterized in that the filler is solidified while a magnetic field is applied in intersecting directions.