JP2001093744A - Thin inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin inductor which is composed of a small number of components, can be mounted on either surface, and is free of deterioration in functions due to an electrical leakage and superior in insulation. SOLUTION: A coil 30, whose both end lead-out parts 31 extend, in one direction and a pair of coil storage parts 12, which contain the coil 30 when put together opposite each other, are formed and further the inductor is equipped with a couple of magnetic cores 40 and 50 having internal surfaces, surrounding the coil storage parts, coated with electrical insulating films and a couple of metal fixers 20, which are formed of two rectangular boxes each having one surface absent, contains both different directional end parts of the couple of magnetic cores, and have a couple of terminals 21, where the tips of the lead-out parts are connected electrically, fitted to the external surfaces where the lead- out parts are present. This thin inductor has the electrical insulating films, made preferably of an organic high polymer, metal oxides, or metal nitrides.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inductor having a winding and a magnetic core, and more particularly to a thin inductor.

[0002]

2. Description of the Related Art FIG. 2 is a perspective view showing the structure of a conventional mounting inductor. The main part of this inductor is a ferrite core 71, 72 of the type described above (in the figure, simply referred to as a magnetic core).
The same applies to the following), and a coil that exposes both ends 74 and 75 to the opening 73 of the ferrite core (not visible).
A U-shaped connection terminal 76 is provided at one end of the ferrite core 71 and is mounted so as to sandwich the ferrite core.
77 and a fixing bracket 78 that can be disassembled. The connection terminals 76 and 77 have projections 76a and 77a, respectively.
75 are connected.

[0003]

In the conventional inductor as described above, the terminals 76 and 77 and the fixing bracket 78 are used.
Have a disadvantage that they have a large number of components, and the terminals 76 and 77 are attached to one ferrite core (72 in this case). Had the disadvantage of having to do so. Ferrite used as a magnetic core generally has a DC specific resistance of about 3000 Ω · cm. However, when a high frequency is applied, the specific resistance decreases to about several tens of Ω · cm. Had been a problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thin inductor which has a reduced number of components, can be mounted on both sides, and has excellent insulation without a decrease in function due to electric leakage.

[0005]

According to the present invention, there is provided a coil whose leading portions at both ends extend in one direction, and a coil accommodating portion for accommodating the coil when the two are opposed to each other, And a pair of magnetic cores whose inner surfaces surrounding at least the coil accommodating portion (at least a portion in contact with the coil) are covered with an electric insulating film, and two rectangular box-shaped members each lacking one surface in the longitudinal direction, The pair of magnetic cores accommodates both ends of the magnetic core in another direction orthogonal to the one direction, and on the outer surface of the two rectangular box-shaped sides on which the lead-out portions are provided,
A thin inductor is provided, comprising a pair of fixing brackets attached so that a pair of terminals for electrically connecting the ends of the lead portions at both ends are opposed to each other.

In the above-mentioned thin inductor, the above-mentioned electric insulating film is formed of an organic polymer film, a metal oxide film,
Alternatively, it may be a metal nitride film. Further, as the organic polymer film, an organic polymer film containing at least one of a v-epoxy resin film, a fluorine-based polyimide amide resin film, an acrylic resin film, an alkyd resin film, and a phenol resin film. Preferably, the metal oxide film is a metal oxide containing SiO ₂ , and the metal nitride film is a metal nitride film containing at least one of an AlN film and a TiN film. It is preferably a coating.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a view showing a configuration of a thin inductor according to an embodiment of the present invention.
(A) is an exploded view as viewed obliquely, and (b) is an external view as viewed obliquely. However, their dimensional ratios are different. First, the outline of the configuration will be described with reference to FIG. 1B. This thin inductor is provided with a lead portion 31 of a coil housed therein.
Ferrite core 40 having opening 11 for drawing out
And 50, and a pair of fixtures 20 for accommodating both sides of the ferrite core. Opening 11 of this fixture
The connection terminals 21 are attached to the outer surface on the side of the side facing each other, and the exposed distal end of the lead-out portion 31 is connected. The ferrite cores 40 and 50 and the internal coil are collectively referred to as an inductor body 10.

Next, the internal details will be described with reference to FIG. The ferrite cores 40 and 50 are provided at the center with a recess 15 for receiving the winding part 32 of the coil 30 and a groove 16 for drawing out the lead-out part 31 to the outside. The coil receiving portion 1 including the recess 15 and the groove 16
2, the main part of the inner surface of the ferrite cores 40, 50 surrounding the coil accommodating part 12, that is, at least the part that may come into contact with the coil 30, is made of a fluoropolyimide amide resin for the purpose of electrical insulation. 1 after application
It is baked at 50-250 ° C. Winding part 32
At the center of the recess 15 for accommodating the pedestal 15, there is provided a base 14 having a circular shape and the height of the upper surface is equal to the height of the edge 13. The groove 16 described above is a groove 17 provided symmetrically with this.
In addition, it has a width slightly smaller than the diameter of the depression 15.
Further, following the groove 16, there are provided step portions 18 and 19, which form a step higher than the bottom of the groove 16.

The winding part 32 of the coil 30 is formed by winding a conductor in a circular shape, and both ends of the circle formed by the conductor, which extend in parallel in the same direction, are drawn out from opposing positions of a circle formed by the conductor. 31.

The fixing bracket 20 is in the form of a rectangular box with one side open, and accommodates the ends of the ferrite cores 40 and 50. In the box-shaped opening 11 side, 2
The two connection terminals 21 are mounted so as to protrude outward at positions facing each other.

Next, assembly of a thin inductor according to an embodiment of the present invention will be described. First, the coil 30 is housed in the recess 15 of the ferrite core 40, and the lead portions 31, 3 at both ends are provided.
When the lid 1 is projected from one end and covered with a ferrite core 50 and joined, a rectangular parallelepiped inductor body 10 is formed. Next, connection terminals 2 are provided on both sides of the inductor body.
1 is attached to the connecting terminal 21, the lead portions 31, 31 are respectively connected to the connection terminals 21, and a tape is wound around the inductor body so as to press the fixing metal 20, thereby completing a thin inductor. .

As described above, the terminal 21 is attached to the magnetic core fixing member 20.
Is provided, the number of components is reduced from two to one in comparison with the conventional magnetic core fixing and separate equipment, and a rectangular magnetic core fixing bracket 20 lacking one surface is provided. Are used facing each other, so that there is no need to distinguish between the front and back sides when mounting on a board.

Further, even when a Mn-Zn ferrite having a low resistance at a high frequency is used as a material of the ferrite core, a short circuit or the like does not occur because the surface is coated with a fluorine-based polyimide amide as an electric insulating film. Mn-Z
The thin inductor was produced using n ferrite as a magnetic core material, and the electric resistance between the fixed pieces was measured. At this time, an inductor not coated with the fluorine-based polyimide amide was also produced as a comparative material, and the distance between the fixing pieces was set to 1 mm. As a result of measuring the electric resistance at 1 MHz, it was 3800 Ω · cm in the case of the present invention, whereas it was 150 Ω · cm in the conventional case without coating. That is, the electrical resistance of the product of the present invention is 10 times or more as compared with the comparison material
It can be seen that the insulation is extremely excellent.

Example-2: Mn-Z shown in Example-1
In a thin inductor using an n-based ferrite, when using an Mn-Zn-based ferrite that does not form the resistor at 1 MHz when the epoxy resin, acrylic resin, alkyd resin, or phenol resin is used as the electric insulating film. And compared. Also in this case, the distance between the fixing pieces was 1 mm.

Table 1 below shows the resins used in this example, the conditions for forming the coating, the film pressure, and the electrical resistance. In each case, it can be seen that the product of the present invention has higher electric resistance and better insulation. This electric resistance shows a value at 1 MHz at normal temperature.

[0016]

[Table 1]

Example-3 Mn-Z shown in Example-1
SiO ₂ , TiO ₂ , NiO, Al as an electric insulating film in a thin inductor using n-based ferrite
₂ O ₃ was formed by a sputtering method. Further, the electrical resistance (normal temperature, 1 MHz) when a thin inductor was formed and the distance between the fixing pieces was 1 mm was compared with the case where an Mn—Zn-based ferrite without a coating was used. Table 2 below shows a comparison table of the electric resistance. In each case, it is shown that the present invention has remarkably high electric resistance and excellent insulating properties.

[0018]

[Table 2]

Example-4: Mn-Z shown in Example-1
AlN ₂ , TiN, and Si ₃ N ₄ were formed by a sputtering method as an electric insulating film in a thin inductor using n-based ferrite. Resistance measurement was performed with the distance between the fixed terminals of the thin inductor using these cores being 1 mm. In Table 3 below, the electrical resistance at 1 MHz when these nitride films were formed was reduced by Mn-
The result of comparison with the case using Zn ferrite is shown.
From Table 3, it can be seen that the thin inductor formed with nitride has remarkably high electric resistance and excellent insulation properties.

[0020]

[Table 3]

The above description has been made in connection with the shape and material of each component used in the thin inductor. Next, a method of coating various coatings on the ferrite core will be described.

As for the organic polymer material, it is preferable from the viewpoint of cost that the material is applied by general spraying or dipping and then baked. Furthermore, when using the plasma polymerization method,
The degree of adhesion is remarkably improved, and it is possible to coat a substance slightly different from a conventional organic polymer.

Metal oxides (SiO ₂ , Al
₂ O ₃ , TiO ₂ etc.), metal nitride (AlN, S
i ₃ N ₄ etc.) are sputter, ion plating,
Any of dry processes such as vapor deposition and P-CVD can be used. For metal oxides, it is also possible to use a coating technique of forming a film by hydrolysis of an alcoholate and a heating method, and after applying sealing glass as a paste,
It is also possible to form by heating.

In any method, cost, workability, and function can be freely selected according to the application. For the thickness of the coating, it is necessary to select a coating suitable for various coating films, and the organic polymer is preferably 10 μm or more. However, if the thickness is too large, it becomes difficult to form the inductor, and there is a possibility that the inductor may be lowered due to stress from various coatings. Therefore, the thickness of the organic polymer needs to be 150 μm or less. In the case of metal oxides and metal nitrides, the thickness is preferably 10 to 50 μm.

[0025]

As described above, according to the present invention,
It is possible to provide a thin inductor having the advantages of reducing the number of components, eliminating the need for distinction between front and back, and maintaining the insulating properties of the ferrite core even at high frequencies.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a thin inductor according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a conventional thin inductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inductor main body 11 Opening 13 Edge 14 Stand 15 Depression 16, 17 Groove 18, 19 Step 20 Fixing fixture 21 Connection terminal 30 Coil 31 Leader 40, 50 Magnetic core (ferrite magnetic core) 71, 72 Magnetic core (ferrite magnetic core) 73 Opening 74, 75 End 76 Connection terminal 76 a Projection 77 Connection terminal 77 a Projection 78 Fixing bracket

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 37/00 H01F 37/00 GF Term (Reference) 4F073 AA32 BA18 BA21 BA22 BA23 BA31 5E043 AA01 AB01 BA01 EA06 EB02 EB03 EB05 5E070 AA01 AB01 BA08 BB01 DA15 DB06 EA02 EA09

Claims (5)

[Claims] 1. A coil having drawer portions at both ends extending in one direction and a coil housing portion for housing the coil when two are opposed to each other are formed, and an inner surface surrounding the coil housing portion is formed. At least a portion in contact with the coil) is formed of a pair of magnetic cores coated with an electric insulating coating, and two rectangular box-shaped ones each of which is cut off in one longitudinal direction. A pair of terminals accommodating both ends in the other direction orthogonal to one direction, and electrically connecting the tips of the drawers at both ends to the outer surface on the side where the drawers of the two rectangular boxes are provided. A thin inductor comprising: a pair of fixing brackets mounted so as to face each other. 2. The thin inductor according to claim 1, wherein the electric insulating film is an organic polymer film, a metal oxide film, or a metal nitride film. 3. An organic polymer containing at least one of an epoxy resin film, a fluorine-based polyimide amide resin film, an acrylic resin film, an alkyd resin film, and a phenol resin film. 3. The thin inductor according to claim 2, wherein the inductor is a molecular coating. 4. The method according to claim ₂ , wherein the metal oxide film is a metal oxide film containing SiO 2.
The thin inductor as described. 5. The thin inductor according to claim 2, wherein the metal nitride film is a metal nitride film containing at least one of an AlN film and a TiN film.