JPH08306541A - Chip inductor array, and its manufacture - Google Patents

Abstract

PURPOSE: To mount plural pieces on a wiring board easily by arranging and burying a plurality of coil-shaped lead wires within a magnetic core, and connecting both terminals of each to external electrodes made at both ends of a magnetic core. CONSTITUTION: Four coil-shaped lead wires 21 -24 are arranged and buried in parallel at specified intervals in a magnetic core 1. Both terminals 31 and 32 each of the coil-shaped lead wires 21 -24 are connected to the external electrodes 41 and 42 made at the front and rear of the magnetic core 1. These external electrodes 41 and 42 are extended each to the top and bottom and facilitate the connection to the conductive pads when mounted on a wiring board. Moreover, all the coil-shaped lead wires 21 -24 are buried in the magnetic core 1, and the magnetic fluxes generated by the coil-shaped lead wires 21 -24 flow within the magnetic core 1, and do not leak outside, so a small-sized inductor array with large impedance can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact high impedance chip-shaped inductor array and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a small-sized, high-impedance chip-shaped inductor, one in which a coil-shaped conductor is embedded in a magnetic core has been proposed.

[0003]

The conventional inductor has a small size and can obtain a high impedance, but there is a problem that it takes time and effort to mount a plurality of inductors on a wiring board.

The present invention provides a small-sized, high-impedance chip-shaped inductor array that solves the above-mentioned conventional problems, and a manufacturing method capable of manufacturing such a chip-shaped inductor array at low cost. Its purpose is to provide.

[0005]

In order to achieve the above object, the chip-shaped inductor array of the present invention has a plurality of coil-shaped conductive wires arranged in parallel and embedded inside a magnetic core. Both ends of the coil-shaped conductor are connected to external electrodes formed on both end surfaces of the magnetic core. It is desirable that both ends of each of the plurality of coil-shaped conductors are exposed linearly on both end faces of the magnetic core and are connected to the external electrodes, for example, by reducing the winding pitch of the coil-shaped conductors. A method for manufacturing a chip-shaped inductor array according to the present invention forms a plurality of rods made of a kneading material arranged in parallel by a primary extrusion molding machine into which a kneading material obtained by kneading a magnetic raw material powder and a binder is fed. Then, the conductor wires are wound in a coil shape on the plurality of rods arranged in parallel, and then the conductor wires are wound in a coil shape by a secondary extrusion molding machine into which the kneading material is fed and arranged in parallel. A plurality of rods are continuously surrounded to form an outer casing made of a kneading material, and then the plurality of rods and the outer casing are fired and then cut into a predetermined length to form a plurality of coils. A plurality of inductor array bases in each of which a conductor wire is embedded in a magnetic core are formed, and a conductive paste is applied to both end faces of each magnetic core of the plurality of inductor base arrays and baked to form a plurality of exposed coil-shaped conductors. Connect to both terminals Characterized in that the formation of the external electrodes.

[0006]

In the inductor array of the present invention, since the plurality of coil-shaped conductors are arranged and embedded in parallel inside the magnetic core, there is no leakage of magnetic flux due to the coil-shaped conductor, and therefore the impedance of each coil-shaped conductor is reduced. Is big. Moreover, the mounting work can be performed more easily than when a plurality of chip-shaped inductors are arranged side by side on the wiring board. When both ends of each coiled conductor are exposed linearly on both end faces of the magnetic core, the contact area between the ends of the coiled conductor and the external electrodes connected thereto increases, and even if a large pulse current flows,
It is difficult for disconnection and connection failure to occur at this connection portion.

In the method of manufacturing an inductor according to the present invention,
A plurality of rods made of a kneaded material arranged in parallel by a primary extrusion molding machine is formed, and a conductor is wound around each of the plurality of parallelly arranged rods in a coil shape, and then a secondary extrusion molding machine is formed. The conductors are respectively wound in a coil shape and a plurality of rods arranged in parallel are continuously surrounded by an outer casing made of a kneading material, and then the plurality of rods and the outer casing are fired and then predetermined. To form a plurality of inductor array bases in which a plurality of coiled wires are embedded in a magnetic core, and a conductive paste is applied to both end faces of each magnetic core of the plurality of inductor array bases. Apply, bake,
Since the external electrodes respectively connected to both ends of the exposed plurality of coiled conductors are formed, a plurality of chip-shaped inductor arrays are manufactured almost at the same time.

[0008]

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

FIG. 1 shows an example of a chip-shaped inductor array according to the present invention.

In the figure, 1 is a magnetic core made of rectangular parallelepiped ferrite, for example, four coil-shaped conductors 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ are arranged in parallel at a predetermined interval. Embedded in the coil-shaped conductors 2 ₁ , 2 ₂ , 2 ₃ ,
2 each both terminals 3 ₁ of _4, 3 ₂ are connected to the external electrodes 4 _1, 4 ₂ formed on front and rear surfaces of the magnetic core 1. Since the external electrodes 4 ₁ and 4 ₂ are easy to connect to the conductive pads when mounted on the wiring board, it is desirable to extend the electrodes to the upper and lower surfaces, respectively. According to this inductor configuration, the coil-shaped conductors 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ are all embedded in the magnetic core 1, and the magnetic flux generated by the coil-shaped conductors 2 ₁ to 2 ₄ flows into the magnetic core 1. Since it does not leak to the outside, a high-impedance, small-sized inductor array can be obtained.

Next, a method of manufacturing this chip-shaped inductor will be described.

In FIG. 2, 5₁Is a primary extrusion molding machine
Then, from inside the kneading material feeding part 5a to the kneading machine 6₁smell
The binder S and the magnetic material powder B uniformly at an appropriate mixing ratio.
Kneading material 7 kneaded into₁Is supplied under pressure, the primary extrusion is completed.
Shape machine 5₁The cross-sectional shape from the die 5b, which is the outlet of the
4 molded bodies 8 made of kneaded material in the shape of, for example, 30 m / min
Is extruded at a speed of. These four molded bodies 8 are dried, for example.
After drying with a dryer (not shown), the winding machine 9
Four molded bodies 8 obtained by winding 10 and winding the conductor 10.
Secondary extrusion molding machine 5₂Send to. This secondary extrusion
Shape machine 5₂In advance, the kneading machine 6₂Kneading with
Material 7₂Is supplied under pressure, so this secondary extrusion molding
Machine 5₂From the die 5b at the outlet of the four molded bodies 8 and it
The four conductive wires 10 each wound around the kneading material 7₂In a row
Then, the outer cover 11 is formed by coating. After this, baked
The size of the reactor (not shown) or the setter laid below (see figure
Cut according to the shape (not shown). And this
Induct by firing at 600-1000 ° C, for example 900 ° C
After creating the data array substrate assembly,
Align individual inductor array dimensions along the length of the line
Let it cut with a cutter. 12 is a cutter cut with a cutter
It is the inductor array substrate. This inductor array
As described above, the base 12 is a coil-shaped conductive wire in the magnetic core 1.
2₁~ 2_FourIs buried and both terminals 3₁Three₂But
It is linearly exposed on the front surface and the rear surface of the magnetic core 1. Next
Then, in front of the magnetic core 1 of this inductor array substrate 12.
Apply silver paste consisting of silver powder and solvent on the front and back surfaces.
Cloth and bake external electrodes 4₁Four ₂To form Hiding
The four coil-shaped conductors 2 of the inductor body 12₁~ 2
_FourIs the external electrode 4₁Four₂Connected to. External power
Pole 4₁Four₂The silver layer of the
The key is applied.

When the winding pitch of the coil-shaped conductors 2 ₁ to 2 ₄ is reduced and the inductor array base body assembly is cut according to the size of each inductor array, the end face of the inductor array base body 12 is As shown in FIG. 3, when the terminals 3 ₁ and 3 ₂ of the coil-shaped conductors 2 ₁ to 2 ₄ are exposed in a circular arc shape, the external electrodes 4 ₁ and 4 ₂ formed on the end face have a circular arc shape. Exposed terminals 3 ₁ and 3 ₂
Are connected, and the connection area becomes large.

[0014]

The present invention has the effect of providing a chip-shaped inductor array which has a high impedance and is small in size and easy to mount on a wiring board when the above-mentioned structure is adopted. If the winding pitch is reduced and the ends are exposed linearly on both end faces of the magnetic core, the connection area between the ends and the external electrodes increases, so even if a large pulse current flows, disconnection or connection failure occurs at the connection. It is possible to obtain an effect that is unlikely to occur and to obtain a manufacturing method that can manufacture the chip-shaped inductor array at low cost.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing an example of a method for manufacturing the inductor according to the present invention.

FIG. 3 is a cross-sectional view of an inductor array that is another embodiment of the present invention.

[Explanation of symbols]

1 magnetic core 2 _{1 to} 2 ₄ coiled conductive wire 3 _{1 to} 3 ₃ terminal 4 ₁ and 4 ₂
External electrodes 5 ₁ , 5 ₂ Extrusion molding machine 9
Winding machine 12 Chip type inductor array substrate

Claims (3)

[Claims] 1. A plurality of coil-shaped conductors are arranged in parallel and embedded inside a magnetic core, and both ends of the plurality of coil-shaped conductors are connected to external electrodes formed on both end faces of the magnetic core. A chip-shaped inductor array. 2. The chip-shaped inductor array according to claim 1, wherein both ends of each of the plurality of coil-shaped conductors are linearly exposed on both end faces of the magnetic core and connected to external electrodes. 3. A plurality of rods composed of the kneading materials arranged in parallel are formed by a primary extrusion molding machine into which the kneading material obtained by kneading the magnetic raw material powder and the binder is fed, and the rods are arranged in parallel. After winding the conductor wire around each of the multiple rods in a coil,
A secondary extrusion molding machine into which the kneading material is fed forms a kneading material that continuously surrounds a plurality of rods in which conductor wires are wound in a coil shape and arranged in parallel, and then forms a jacket.
After firing the plurality of rods and the outer casing, cutting them into a predetermined length to form a plurality of inductor array bases in which a plurality of coil-shaped conductors are embedded in a magnetic core, respectively. Manufacture of a chip-shaped inductor array, characterized in that both ends of each magnetic core of the array base are coated with a conductive paste and baked to form external electrodes respectively connected to both ends of the exposed plurality of coil-shaped conductors. Method.