JPH04115507A - Inductor - Google Patents

Abstract

PURPOSE:To make it possible to prepare a high performance inductor superior in magnetic body filling by making powder binder contain thermal hardening resin that becomes solid at room temperature when the powder binder does not yet react for hardening. CONSTITUTION:Air core coil 4 already connected to a terminal 5 is filled with magnetic powder 3 prepared by distributing and mixing therein epoxy resin thermosettable powder binder 2 which is solid powder until hardening reaction at a mixing weight ratio of about 1/20 to iron metallic magnetic powder 1, followed by molding the magnetic powder 3 with pressure, further followed by heating the molded magnetic powder to harden. When filling the inductor 6 thus prepared with magnetic powder, its powder fluidity becomes so high that the magnetic powder can securely flow into every space in the lower section of coil 4 and the neighborhood of inner holes and terminals. With this, the failure that occurs when filling the inductor with magnetic powder can be resolved and a highly reliable inductor with a large induction coefficient can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an inductor that is included in an electronic circuit or the like and has a coil embedded in a magnetic body. The present invention relates to an inductor configuration that eliminates the filling problem.

[Prior art] Conventional inductors are manufactured by mixing magnetic powder and a binder to produce a magnetic material, then filling and press-molding a coil with terminals at both ends so as to bury it inside the magnetic material, and then thermosetting the material. It was obtained by

A low-viscosity liquid resin was used as the binder in order to obtain powder fluidity during filling.

[Problems to be Solved by the Invention] However, in conventional inductors, even if low-viscosity liquid resin is used, the powder fluidity of the magnetic material is relatively low, making it difficult to wrap around the complex shapes of internal fillings such as coils. There were problems such as filling problems such as.

SUMMARY OF THE INVENTION In view of the above drawbacks, a technical object of the present invention is to provide a high-performance inductor with excellent magnetic filling properties.

[Means for Solving the Problems] According to the present invention, in an inductor including a magnetic body formed by mixing magnetic powder and a powder binder, and a coil embedded in the magnetic body, the powder binder An inductor is obtained which is characterized by containing a thermosetting resin that is solid at room temperature when not cured and reacted.

Further, according to the present invention, a powder binder containing a thermosetting resin that is solid at room temperature when uncured and unreacted is dissolved in a predetermined solvent, and then mixed with magnetic powder and dried to form a magnetic material. An inductor is obtained in which a coil is embedded in the magnetic material obtained.

[Function] By using a resin that is solid at room temperature when not cured and reacted as a powder binder, the fluidity of the mixed powder of magnetic powder and resin during filling can be increased.

Therefore, it becomes easy to wrap around the complicated shape of an internal filling such as a coil.

Furthermore, the effective magnetic permeability of the magnetic material is improved by effectively increasing the packing density with respect to a constant pressing force.

In addition, by mixing resin and magnetic powder dissolved in a solvent in advance,
The resin-mixed magnetic powder obtained by drying spreads the resin to each magnetic powder, so there is no defect in shape strength during subsequent filling inside the coil, and it is highly reliable with a high induction coefficient and no filling defects. A magnetic inductor is obtained.

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

First example- A first embodiment of the present invention will be described with reference to the drawings.

In Figure 1, epoxy resin-based unreacted solid thermosetting powder binder 2 is dispersed and mixed at a weight ratio of about 1/20 to 1 iron-based metal magnetic powder using a mixer such as a mill. The binder-containing magnetic powder 3 thus prepared was filled into an air-core coil 5 connected to a terminal 6, pressure-molded, and then cured by heating.

The inductor configured in this way has high powder fluidity during powder filling, and the powder reliably flows around the lower part of the coil a, the inner hole, and the vicinity of the terminal C shown in Figure 2, which is different from conventional powder filling. This problem has been resolved and the resistance to pressure filling of the powder has been reduced, so compared to the conventional method, a larger magnetic powder filling rate can be obtained with a constant pressure, the effective magnetic permeability of the molded body has improved, and the induction coefficient has been reduced. A large and highly reliable inductor was obtained.

In addition, the magnetic powder in this example does not need to be an iron-based metal magnetic powder, and the powder binding resin does not need to be an epoxy resin type, as long as it is solid when hardened and unreacted. Please note that as long as the binder is uniformly dispersed in the resin, it is not necessary to use a powdered resin, and this effect can be obtained with any mixing method other than a mill, or with any magnetic powder resin mixing ratio. Please add a note for this reason.

Soumi below 1.Second embodiment- Next, a second embodiment of the present invention will be described.

In FIG. 3, the epoxy-cured unreacted powder solid thermosetting resin 22 in a weight ratio of about 1/20 to the iron-based metal magnetic powder 21 is dissolved in a ketone-based solvent 23 and mixed with stirring. and evaporate the solvent to dryness. Then, the magnetic powder 25 coated on the resin 2 is applied to the air-core coil 2 connected to the terminal 27.
No. 6 was filled, and after pressure molding, it was cured by heating.

In addition to the effects of the first embodiment, the inductor configured in this manner prevents strength defects in the compact because the resin for the powder binder is spread over each magnetic powder, and also improves the insulation between the magnetic powders. A reliable and highly reliable inductor was obtained.

In addition, similar to the first example, the magnetic powder of the second example is
It does not need to be an iron-based metal magnetic powder, and as long as the powder binding resin is solid when not cured and reacted, it does not need to be an epoxy resin type, and this effect can be applied to any magnetic powder resin mixture ratio. Please note that this can be obtained without any effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the manufacturing process of the first embodiment of the present invention. Fig. 2 is a side sectional view of an inductor in which a coil with terminals connected at both ends is filled inside a magnetic material made of magnetic powder and a powder binder, and Fig. 3 is a schematic diagram of the manufacturing process of the second embodiment of the present invention. . 1.21... Iron-based metal magnetic powder, 2.22... Epoxy resin-based hardening, solid thermosetting powder binder when unreacted, 3... Iron-based metal magnetic powder 1 and epoxy resin-based hardening. Binder-containing magnetic powder obtained by dispersing and mixing unreacted solid thermosetting powder binder 2 with a mixer, 4,11.26.
...Air core coil, 5,12.27...Terminal, 6,13
．． 28...Inductor, 23...Solvent, 24...
A solution obtained by dissolving the epoxy resin-based hardened thermosetting powder in the form of a solid powder when unreacted. Solution 2 obtained by dissolving powder binder 22 in a solvent
Magnetic powder obtained by stirring and mixing 4 and evaporating the solvent to dryness, a...lower part of the coil, b...inner hole of the coil, C...
Near the terminal. Figure 2

Claims (1)

[Claims] 1) A magnetic material formed by mixing magnetic powder and a powder binder;
An inductor having a coil embedded in the magnetic material, wherein the powder binder contains a thermosetting resin that is solid at room temperature when not cured and reacted. (2) After dissolving a powder binder containing a thermosetting resin that is solid at room temperature when uncured and unreacted in a specified solvent, it is mixed with magnetic powder and dried to produce a magnetic material. An inductor characterized by having a coil embedded in a magnetic material.