JPH10135055A - Chip-type common mode choke coil and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common mode choke coil enabling miniaturization, automation of manufacturing systems, large current capacity and surface- mounting, and a method for manufacturing the choke coil at a low cost. SOLUTION: A plurality of coiled lead wire 21 to 24 are embedded in parallel with each other inside a magnetic core 1, and connected to outer electrodes 41 , 42 formed on both ends of the magnetic core 1. Four bars used as wound cores are simultaneously formed in parallel with each other by using a primary extruder, and the coiled lead wire 21 to 24 are wound around the bars respectively. Then a housing covering the coiled lead wire 21 to 24 is formed by a secondary extruder to make a chip-type inductor body, and outer electrodes 31 , 32 are formed on the body. Thereby a chip-type common mode choke coil is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-mountable chip-type common mode choke coil which can be easily miniaturized and automated in manufacturing and can flow a large current, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a chip-shaped common mode choke coil, as shown in FIG. 5, a ring-shaped core d in which a pair of conducting wires c is wound on an insulating base b on which lead terminals a are implanted. And the two ends of the paired conductor c are tangled to the lead terminal a and soldered, or as shown in FIG. 6, the internal electrodes e ₁ and e ₂ and f ₁ and f _{2 respectively.}
Are stacked and fired, and the internal electrodes e ₁ and e ₂ and f ₁ and f ₂ are connected to form a pair of coil conductors.

[0003]

The above-mentioned common mode choke coil shown in FIG. 5 has a problem that it is difficult to automate and reduce the size of the common mode choke coil, and the common mode choke coil shown in FIG. There was a problem that it could not be done.

The present invention provides a surface-mountable common mode choke coil which solves the above-mentioned disadvantages, can be easily reduced in size and can be easily manufactured, and can flow a large current. It is an object to provide a manufacturing method capable of manufacturing a chip-shaped common mode choke coil at low cost.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a plurality of coil-shaped conductors are arranged and embedded in parallel inside a magnetic core, and each of the plurality of coil-shaped conductors is embedded. The terminal is connected to external electrodes formed on both end surfaces of the magnetic core. It is desirable that both ends of the plurality of coiled wires are linearly exposed at both end surfaces of the magnetic core, for example, by reducing a winding pitch of the coiled wires, and are connected to external electrodes. The method for manufacturing a chip-shaped common mode choke coil according to the present invention includes a method of manufacturing a plurality of rods made of kneaded materials arranged in parallel by a primary extruder into which a kneaded material obtained by kneading a magnetic raw material powder and a binder is fed. After the formed and wound wires are wound in a coil shape on the plurality of rods arranged in parallel, the wires are wound in a coil shape by a secondary extruder into which the kneading material is fed and arranged in parallel. A plurality of rods are successively surrounded to form an outer cover made of a kneading material, and then the plurality of rods and the outer cover are baked and cut to a predetermined length, and each of the plurality of rods and the outer cover is cut to a predetermined length. A plurality of inductor bases in which the coil-shaped conductor is embedded in the magnetic core are created, and a conductive paste is applied to both end surfaces of each of the magnetic cores of the plurality of inductor bases, and baked.
An external electrode connected to both ends of the plurality of exposed coiled conductors is formed.

In the common mode choke coil of the present invention, since the plurality of coiled conductors are arranged and embedded in parallel inside the magnetic core, there is no leakage of magnetic flux by the coiled conductor, and therefore, each coiled conductor has Impedance is large, and a common mode choke coil with a coupling coefficient close to 1 can be obtained by reducing the distance between two adjacent coil-shaped conductors. A certain common mode choke coil is obtained.

When both ends of each coil-shaped conductor are linearly exposed on both end faces of the magnetic core, the contact area between the end of the coil-shaped conductor and an external electrode connected thereto becomes large. That is, even if a large pulse current flows, disconnection and poor connection hardly occur at this connection portion.

According to a third aspect of the present invention, a plurality of rods made of a kneading material arranged in parallel are formed by a primary extruder, and conductors are respectively applied to the plurality of rods arranged in parallel. After being wound into a shape, a plurality of rods, each of which is wound in a coil shape by a secondary extruder and arranged in parallel, are continuously surrounded by a jacket made of a kneading material. After firing the rod body and the jacket body, each is cut into a predetermined length to form a plurality of inductor bases each having a plurality of coiled wires embedded in a magnetic core. A common mode choke coil was manufactured by applying and baking a conductive paste to both end surfaces of the core to form external electrodes connected to both ends of the exposed plurality of coiled conductors, respectively. Pot is manufactured at the same time.

[0009]

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

FIG. 1 shows an example of a chip-shaped common mode choke coil according to the present invention.

[0011] In the figure, 1 is a magnetic core made of ferrite having a rectangular parallelepiped shape, including for example, coiled conductors 2 ₁ 2, 2 ₂ are embedded is disposed in parallel at predetermined intervals, the coil Jo conductors 2 _1, 2 ₂ of the both terminals 3 _1, 3 ₂
Are connected to external electrodes 4 ₁ , 4 ₂ formed on the front and rear surfaces of the magnetic core 1. The external electrodes 4 ₁ and 4 ₂
Since it is easy to connect to the conductive pads when mounted on a wiring board, it is preferable to extend the respective upper and lower surfaces. According to the configuration of the common mode choke coil, coiled conductors 2 _1, 2 ₂ of the both terminals 3 _1, 3 ₂
Part excluding the are all embedded in the magnetic core 1, a coil-shaped conductive wire 2 _1, 2 ₂ Thus resulting magnetic flux flows in the magnetic core 1, since there is no leak to the outside, impedance is large, a small common mode choke A coil is obtained. In addition, since a conductive wire is used, a large current can be made to flow by increasing its diameter.

When the interval between the two coiled conductors 2 ₁ and 2 ₂ is reduced, a common mode choke coil having a coupling coefficient close to 1 is obtained. An effective common mode choke coil is obtained. FIG. 2 shows another example of the common mode choke coil according to the present invention.

The chip-shaped common mode choke coil is provided with a magnetic core 1 made of a rectangular parallelepiped ferrite,
Coiled conductors 2 of _the present, 2 _2, 2 ₃ and 2 ₄ are embedded are arranged in parallel at predetermined intervals, the coil-shaped conductive wire 2 _1, 2
_2, 2 ₃ and 2 each both terminals 3 ₁ of _4, 3 ₂ similar to that shown in FIG. 1, is connected to the external electrodes 4 _1, 4 ₂ formed on front and rear surfaces of the magnetic core 1. Other configurations are the same as those shown in FIG.

[0014] The chip-like common mode choke coil, the two coiled conductors 2 _1, 2 _2, for example, inserted and connected to the audio circuit of the television receiver, the coiled conductors other two 2 ₃ and 2 ₄ Is inserted and connected to the video circuit and the other is inserted and connected to the ground circuit.

Next, a method for manufacturing the chip-shaped common mode choke coil of the present invention will be described with reference to the example shown in FIG.

[0016] In FIG. 3, 5 ₁ primary extruder, uniformly kneaded binding material S and the magnetic material powder B in a suitable mixing ratio in the mixer 6 ₁ from the kneading material fed join the club 5a therein in the When a kneaded material 7 ₁ to the pressure supply, the primary extruder 5 ₁ of the four molded body 8, for example, 30 m / min cross-sectional shape from the mold 5b is composed for example of a circular kneading material is an outlet Extruded. After drying these four compacts 8 with, for example, a drier (not shown), a wire 10 is wound by a winding machine 9, and the four compacts 8 around which the wire 10 is wound are wound.
To pumped into the secondary extruder 5 _2. The secondary extruder 5 _2, in advance, since the kneaded material 7 ₂ were kneaded with a kneading machine 6 ₂ is supplied under pressure from the secondary extruder 5 _second outlet of the mold 5b, 4 shaped body 8 and four conductors 10 of it are respectively wound of this is continuously coated with a kneading member 7 _2, envelope body 11 is formed. Thereafter, cutting is performed according to the size of a firing furnace (not shown) or the shape of a setter (not shown) to be laid below. Then, this is fired at 600 to 1000 ° C., for example, 900 ° C., to form an inductor base body assembly, which is cut by a cutter in the length direction of the coiled conductor in accordance with the size of each inductor. Reference numeral 12 denotes an inductor base cut by a cutter. The inductor green body 12 is embedded coiled wire _{21 to 24} in the magnetic core 1, as described above, each of the both terminals 3 _1, 3 ₂ is exposed to the front and rear surfaces of the magnetic core 1. Next, the magnetic core 1 of the inductor base 12
A silver paste composed of silver powder and a solvent is applied to the front and rear surfaces of the substrate and baked to form external electrodes 4 ₁ and 4 ₂ . Thus, the four coiled conductors 2 _{1 of} the inductor base 12
21 to ₂₄ are connected to the external electrodes 4 _1, 4 _2, respectively. The external electrodes 4 _1, 4 ₂ of the silver layer is subjected to a nickel plating and solder plating. The winding pitch of the coil-shaped conductors ₂₁ to ₂₄ with a smaller inductor green body 1 when cutting the inductor green body assembly to the dimensions of the individual inductors
The end face 2, the coiled wire as shown in FIG. 4 2 ₁ to 2 ₄
When the terminals 3 ₁ and 3 ₂ are exposed in an arc-shaped line, the terminals 3 ₁ and 3 _{2 that} are exposed in an arc-shaped line are connected to the external electrodes 4 ₁ and 4 ₂ formed on the end face. , The connection area becomes large.

[0017]

According to the present invention, when the above-mentioned structure is employed, it is easy to reduce the size and automate the production, and it is possible to obtain a surface-mountable common mode choke coil capable of flowing a large current. However, if the winding pitch of the coil-shaped conductor is reduced and its terminals are exposed linearly on both end surfaces of the magnetic core, the connection area between the terminals and the external electrodes increases, so that even if a large pulse current flows, the connection portion is not An effect is obtained in that disconnection or poor connection is unlikely to occur, and a manufacturing method capable of manufacturing the chip-shaped common mode choke coil at low cost is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of a common mode choke coil according to the present invention.

FIG. 2 is a perspective view of another example of the common mode choke coil of the present invention.

FIG. 3 is an explanatory diagram illustrating an example of a method for manufacturing a common mode choke coil according to the present invention.

FIG. 4 is a sectional view of a modification of the common mode choke coil shown in FIG. 2;

FIG. 5 is a perspective view of an example of a conventional common mode choke coil.

FIG. 6 is an exploded perspective view showing a main part of another example of the conventional common mode choke coil.

[Explanation of symbols]

1 magnetic cores ₂₁ to ₂₄ coil conductors 3 ₁ to 3 ₃ terminal 4 _1, 4 ₂
External electrodes 5 _1, 5 ₂ extruder 9
Winding machine 12 Inductor base

Claims (3)

[Claims] 1. A plurality of coiled conductors are arranged and embedded in parallel inside a magnetic core, and both ends of the plurality of coiled conductors are connected to external electrodes formed on both end surfaces of the magnetic core. A chip-shaped common mode choke coil. 2. The chip-shaped chip common mode according to claim 1, wherein both ends of said plurality of coil-shaped conductors are linearly exposed on both end faces of the magnetic core and connected to external electrodes. choke coil. 3. A plurality of rods composed of kneaded materials arranged in parallel by a primary extruder into which a kneaded material obtained by kneading a magnetic raw material powder and a binder is fed, and the rods are arranged in parallel. After winding the conductor in a coil shape on each of multiple rods,
The secondary extruder into which the kneading material has been fed forms a jacket made of the kneading material in which the conductive wire is wound in a coil shape and continuously surrounds a plurality of rods arranged in parallel.
After sintering the plurality of rods and the jacket, the plurality of inductors are cut to a predetermined length to form a plurality of inductor bodies each having a plurality of coiled wires embedded in a magnetic core. A method for manufacturing a chip-shaped common mode choke coil, characterized in that a conductive paste is applied to both end faces of the magnetic core and baked to form external electrodes respectively connected to both ends of the plurality of exposed coil-shaped conductors.