JPH04118905A - Induction electromagnetic device - Google Patents

Abstract

PURPOSE:To enhance the permeability of a core as a whole by a method wherein fine particles composed of a ferromagnetic substance whose particle size can form a magnetic fluid are inserted between both split faces of split cores and a fixation means used to fix the split cores to each other is installed. CONSTITUTION:Split faces 54 of E-shaped split cores 51, 51 are polished and finished by abrasive grains whose particle size is at 30mum. Fine particles 10 of a ferromagnetic substance whose particle size can form a magnetic fluid are inserted in a gap G between both of the split cores 51, 51. Both of the split cores 51, 51 are fixed to each other in such a way that several places at the outer circumference of the split faces 54 at the side faces 51 are coated with an adhesive (fixation means) 11 composed of an epoxy resin or a silicone resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an 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 have been split-type high-frequency chokes and transformers in which a core made of a soft magnetic material is divided into a plurality of parts. An example of this is shown in FIG.

In FIG. 8, the core 50 of the high frequency choke consists of two divided cores (hereinafter referred to as split cores) 51, 51, and these split cores 51, 51 have windings 52.
52 is wrapped around it. This winding 5252 is balanced so that the magnetic fields generated by the current from the input source are in opposite directions.

The two divided cores 51.51 are pressed against each other in the direction of the arrow P by a compression spring (not shown).

This type of split-type high-frequency choke is easier to attach the core to the coil by inserting the split core into the coil 51, 52 that has been wound around a bobbin in advance, compared to one in which a closed magnetic path is formed by an undivided core. It has the advantage of being inexpensive.

[Problem to be solved by the invention]

However, due to the compression spring, the two split cores 51°51
Even if the cores 5 and 5 are pressed against each other, as shown in the enlarged view of FIG.
Since minute irregularities H and cracks C exist on the dividing surface 54 of the core 1, it is inevitable that a near gap will occur, and as a result, the magnetic permeability of the entire core 50 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 drops to about 50%, or about 5.000. 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 1.4 times compared to the undivided core. Therefore, the electrical resistance and distributed capacitance due to winding @52 increase, and as a result, the high frequency channel a
- This leads to the problem that the properties of the resin deteriorate.

On the other hand, the smoothness of each dividing surface 54 is set to submicron (1.0 μm).
By finishing the material to less than 70%, the magnetic permeability can be restored to about 70%. However, finishing the dividing surface 54 with high precision in this way leads to a significant increase in cost, which negates the advantage of the originally inexpensive divided core 50.

On the other hand, adhesives containing fine ferromagnetic particles with a particle size of 1 μ or more are known (for example, disclosed in Japanese Patent Application Laid-Open No. 1-28457).
(Refer to Publication No. 3), it is also possible to use such an adhesive to adhere the cores 51 and 51 on both sides to each other, but if fine particles with a relatively large particle size are inserted into the air gap A, Since the air gap A widens, the magnetic permeability actually decreases unless fine particles with extremely high magnetic permeability are used.

This invention was made in view of the above-mentioned conventional problems, and in split-type induction electromagnetic devices, it causes a significant increase in cost.
The purpose of the present invention is to provide an induction electromagnetic device whose characteristics can be improved without any problems.

[Means to solve the problem]

In order to achieve the above object, according to the invention of claim (1), fine particles made of a ferromagnetic material having a particle size capable of forming a magnetic fluid are interposed between both divided surfaces of a divided core.

The particle size of these fine particles is usually 1 μm or less, for example, 100 to 400 particles.

In the invention of claim (2), the fine particles of the ferromagnetic material are interposed between the two divided surfaces, and fixing means for fixing the divided cores to each other is provided.

The invention according to claim (3) includes a magnetic fluid inserted between both dividing surfaces, and a sealing material closing the outer periphery of the core between both dividing surfaces.

[Effect]

According to the invention of each claim, since the ferromagnetic fine particles are inserted between the two dividing surfaces, the ferromagnetic fine particles enter into minute irregularities and cracks between the two dividing surfaces and close the air gap. fill in. Moreover, since the ferromagnetic fine particles have a small particle size, they do not widen the air gap.

When an impact force is applied to the core from the outside, the divided cores are displaced from each other and the state of the gap changes, resulting in a decrease in magnetic permeability. Since they are fixed to each other, the magnetic permeability does not decrease even if an external impact is applied.

In particular, in the invention of claim (3), since the sealing material seals the outer periphery of the core at the dividing surface, the dispersant (solvent) of the magnetic fluid inserted between both the dividing surfaces does not evaporate. Therefore, even if an impact force is applied to the core and the divided cores are displaced from each other and the state of the gap changes, the ferromagnetic particles dispersed in the dispersant can fully enter the changed gap.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

1 to 3 show a first embodiment of the invention.

In FIG. 1, the dividing surface 54 of the E-shaped divided core 51.51 is polished and finished with abrasive grains having a particle size of 30 μm. As shown in the enlarged view of FIG. 2, there is a space between the cores 51 and 51 on both sides (hereinafter referred to as "gap").

) Fine particles IO of ferromagnetic material having a particle size sufficient to form a magnetic fluid are inserted in G. Both cores 5 in Figure 1
1.51 is fixed to each other by applying an adhesive (fixing means) 11 made of epoxy resin or silicone resin to several places on the outer periphery of the dividing surface 54 on the side surface 55.

The rest of the structure is the same as that of the conventional example shown in FIG. 8, and the same or corresponding parts are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

Next, a method of manufacturing the above-mentioned high frequency choke will be explained.

First, divide the dividing plane 54 of both divided cores 51 and 51 in Fig.
Winding wire 5 wound on a bobbin after finishing with 0μ abrasive grains
2 is attached to the split core 51. On the other hand, the magnetic fluid 12 shown in FIG. 2 manufactured by the coprecipitation method is applied to each divided surface 54,54. After this application, with each split core 51 and 51 lightly pressed together, as shown in FIG.
By gluing both split cores 51 and 51 together, a high frequency choke is obtained. After this adhesion, the magnetic fluid lz shown in FIG.
Even if the dispersant 14 therein evaporates over time, the fine particles IO remain in the gear G with adhering to the surface of the gap G.

Here, the magnetic fluid 12 is one in which ferromagnetic fine particles 10 stably dispersed using a surfactant are dispersed at a high concentration in the dispersant 14, and is used as a magnetic fluid. Refers to something that shows behavior. Examples of the magnetic fluid I2 include an oxide magnetic fluid containing IO to 25% by volume of ferromagnetic fine particles IO (for example, a manganese-zinc ferrite magnetic fluid), a metal magnetic fluid such as nickel or cobalt, and iron nitride. A magnetic fluid or the like can be used. Further, as the dispersant 14 of the magnetic fluid 12, water or the like can be used in addition to petroleum-based keronine or paraffin. Also,
The particle size of the ferromagnetic fine particles IO is usually 1 μ or less,
For example, about 100λ to 400 people is preferable.

In the above configuration, the ferromagnetic fine particles 0 in the magnetic fluid 12 enter the cracks C and unevenness H of the gap G and fill the gap G. Therefore, the magnetic permeability of the gap G portion is significantly improved, and since the particle size of the fine particles 10 is small, the gap G does not widen, so the magnetic permeability of the entire core 50 in FIG. 1 is not divided. In the case of a core whose relative magnetic permeability is about 10.000, it is 75% to 80% of that.
It recovers to about %.

This recovery in magnetic permeability was obtained regardless of the presence or absence of evaporation of the dispersant 14 (FIG. 2) in the magnetic fluid 12.

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 chime. 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.

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 after the dispersant 14 in the magnetic fluid 12 shown in FIG. 2 has evaporated, 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).

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

After filling the syringe S with the magnetic fluid 12, 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 is forced into the gap G (Fig. 2) due to capillary action. to invade.

Furthermore, by passing a direct current through the windings 52 and 52,
The magnetic fluid 12 receives the magnetic force and penetrates into the cracks C and unevenness H in the gear G shown in FIG.

FIG. 4 shows a second embodiment of the invention.

In FIG. 4, a magnetic fluid 12 is inserted between both dividing surfaces 54,54. The outer periphery of the core 50 at the dividing surface 54 is closed with a sealing material 15 made of, for example, epoxy resin or silicone resin.

Therefore, the dispersant 14 in the magnetic fluid 12 is sealed in the gear G shown in FIG. 2 so as not to evaporate.

In this embodiment, since the magnetic fluid I2 is sealed in the gear G, even if an impact force is applied to the core 50 and the divided cores 51, 51 are displaced from each other and the state of the gap G changes, The ferromagnetic fine particles IO suspended in the dispersant 14 enter the changed gap G. therefore,
Magnetic permeability does not decrease even if a shock is applied.

5 and 6 show a third embodiment of the invention.

Between the dividing planes 54 and 54 in Fig. 5, as shown in Fig. 6,
A filling adhesive 17 made of a resin 16 mixed with ferromagnetic fine particles 10 is inserted and solidified. Therefore, both side cores 51.51 are joined together by the hardened resin 16.

As described above, as an example of a method for inserting and curing the filler adhesive 17 into the gap G, first, a magnetic material is prepared by suspending ferromagnetic fine particles 1O in the monomer of the thermosetting resin 16 as a dispersant. A fluid (filling adhesive 17) is injected into the gap G. Then, the resin 16 is heated and solidified by a polymerization reaction.

In this embodiment, a filling adhesive 17 made of a resin 16 mixed with ferromagnetic fine particles 10 is inserted into the gap G and solidified, so that each divided core 51. ．． 51 are mechanically and firmly joined by the solidified resin 16. Therefore, even if an impact force is applied to the core 50, the two divided cores 51 and 51
do not shift from each other. Furthermore, the ferromagnetic fine particles 10 that have entered the unevenness H or cracks C of the dividing surface 54 during injection or coating will remain in the same state as they were during injection because the resin 16 will solidify. is maintained.

In this way, in this embodiment, it is possible to prevent the positional deviation between the divided cores 51 and 51, and also to prevent the ferromagnetic fine particles 10.
is maintained in the same state as at the time of injection, so there is no risk of magnetic permeability decreasing over time.

By the way, in each of the above Examples, ferromagnetic fine particles 1
In addition to manganese-zinc ferrite and iron nitride powder, ferrite powder containing manganese, iron, nickel, copper, magnesium, etc., mixed powder of iron and cobalt, etc. can be used as the zero.

In particular, by using ferrite or iron nitride, which has a higher magnetic permeability than the ferromagnetic material constituting the divided core 51.51, the magnetic permeability of the entire core 50 can be brought close to the magnetic permeability of the undivided core. .

In particular, when a magnetic fluid made of fine iron nitride particles is used, magnetic saturation does not occur up to a magnetic flux density of 1.700 Gauss.

This has better magnetic properties than ferrite magnetic fluid, which saturates at a magnetic flux density of several hundred Gauss. By concentrating the iron nitride fine particles more than the 10 to 25 volume percent mentioned above, the characteristics can be brought closer to those of an undivided core, making it possible to use them at high magnetic flux densities. .

The ferromagnetic fine particles 10 may be obtained by a chemical synthesis method such as the above-mentioned coprecipitation method, or may be obtained by pulverizing sintered ferrite, a metal magnetic material prepared by a vapor phase method, or a nitrided material. Ferromagnetic fluid or the like can be used.

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

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.

Furthermore, in each of the above embodiments, each split core 51 is E-shaped and the core as a whole is an EE type.
The overall shape of 0 is the El type shown in Figure 7 (breath), and the shape of Figure 7 (
The present invention is also applicable to the ring type shown in b) or the UU type shown in FIG. 7(C).

〔Effect of the invention〕

As explained above, according to each claimed invention, fine particles of ferromagnetic material having a particle size that can form a magnetic fluid enter into the unevenness and cracks of the gap that occurs on the dividing surface of the divided core, and the magnetic permeability of the entire core increases. As a result, the characteristics of the induction electromagnetic device are improved.

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

Furthermore, in the invention of claim (2), since each divided core is fixed to each other, even if an impact force is applied to the core, the state of the gap does not change, so that the magnetic permeability is unlikely to decrease.

Further, according to the invention of claim (3), since the magnetic fluid is sealed in the gap, the magnetic permeability does not decrease.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a high-frequency choke showing a first embodiment of the present invention, FIG. 2 is an enlarged sectional view of a gap, FIG. 3 is a perspective view showing a method of manufacturing a high-frequency choke, and FIG. FIG. 5 is a perspective view of a high frequency choke showing the third embodiment, FIG. 6 is an enlarged sectional view of the gap, ! ! FIG. 7 is a front view showing another example of a core to which the present invention can be applied, FIG. 8 is a perspective view showing a conventional high frequency choke, and FIG. 9 is an enlarged sectional view of the same gap. lO...Ferromagnetic particles, 11...Fixing means (adhesive), 12...Magnetic fluid, 15...Sealing material, 1
6... Resin, 17... Filling adhesive, 50... Core, 51... Split (split) core, 52... Winding wire, 5
4...Dividing surface, G...Gap (between the dividing surfaces).

Claims (3)

[Claims] (1) In an induction electromagnetic device in which a core around which a winding is wound is divided into a plurality of parts, fine particles made of a ferromagnetic material having a particle size capable of forming a magnetic fluid are inserted between both dividing surfaces of the divided core. An induction electromagnetic device characterized by: (2) The induction electromagnetic device according to claim (1), further comprising fixing means for fixing the divided cores to each other. (3) In an induction electromagnetic device in which a core around which a winding is wound is divided into a plurality of parts, a magnetic fluid is inserted between both dividing surfaces of the divided core, and a sealing material that closes the outer periphery of the core at the dividing surface. An induction electromagnetic device comprising: