JP3469613B2 - Chip coil - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip coil which functions as an inductance element.

[0002]

2. Description of the Related Art FIG. 4 and FIG.
There is a structure shown in. In the chip coil shown in FIG. 4, the winding 2 is wound around the outer peripheral surface of the cylindrical ferrite core 1a or the insulator 1b shown in FIG.
Alternatively, cap-shaped external electrodes 3a and 3b made of metal are attached to both ends of the insulator 1b. Both ends of the winding 2 are electrically connected to the external electrodes 3a and 3b, respectively. Further, the mold resin 5 is coated on the outer peripheral portion of the winding 2, and the chip coil is completed.

On the other hand, in the chip coil shown in FIG. 5, the spiral conductor 4 is fixed to the outer peripheral surface of the cylindrical ferrite core 1a or the insulator 1b. And ferrite core 1a
Alternatively, cap-shaped external electrodes 3a and 3b made of metal are attached to both ends of the insulator 1b, and each end of the spiral conductor 4 is electrically connected to the external electrodes 3a and 3b.
In FIG. 4, the mold resin 5 is cut away, and in FIG. 5, the mold resin 5 and a part of the external electrode 3b are cut away.

As a method of fixing the spiral conductor 4 to the outer peripheral surface of the ferrite core 1a or the insulator 1b (referred to as the core 1), first, a groove is formed in the portion of the outer peripheral surface of the core 1 to which the spiral conductor 4 is fixed. To do. Next, a conductive material such as copper is fixed to the entire outer peripheral surface of the core 1 by a method such as plating, vapor deposition, paste baking, etc., and the conductive material fixed to a portion other than the groove is removed by polishing to leave only the conductor. There is.

Further, a conductive material such as copper is fixed to the entire outer peripheral surface of the core 1 by a method such as plating, vapor deposition, paste baking, etc., and the portion other than the spiral conductor 4 is trimmed with a laser or the like to form only the spiral conductor 4. There is also a way to leave.

[0006]

However, the conventional chip coil manufactured by the above-mentioned method has the following problems. That is, in the chip coils shown in FIGS. 4 and 5, the metal-shaped cap-shaped external electrodes 3a and 3b are attached to the ends of the core 1, and the winding 2 or the spoiler-shaped conductor 4 and the external electrode 3a are mounted. , 3b is determined by the number of turns, the winding width, the wire diameter (conductor width), etc. of the winding 2 or the spoiler-shaped conductor 4.

The end faces of the winding 2 and the spoiler-shaped conductor 4 are the parts where the magnetic flux is most concentrated, and if the metallic external electrodes 3a and 3b are present in this part, inside the external electrodes 3a and 3b when the magnetic flux changes. Eddy current is generated. Therefore, there is a problem that the magnetic flux is lost and the Q of the chip coil is lowered. Further, another magnetic flux is generated by the eddy current generated in the external electrodes 3a and 3b, and this magnetic flux hinders the change of the magnetic flux inherent in the chip coil. As described above, there is a problem that the inductance of the chip coil is reduced or the inductance varies.

The present invention has been made in view of such conventional problems, and it is an object of the present invention to realize a chip coil which prevents a decrease in Q and inductance and a variation thereof.

[0009]

The invention of claim 1 SUMMARY OF THE provide a process, a core grooves provided at both ends, a winding wound is <br/> the said core, the ends of the core and a pair of cap-shaped external electrode provided, the groove, the outer peripheral surface of the core
It is formed so that it leads from the
The winding has a spiral conductor spirally wound around the core and a connecting conductor connected to the external electrode, and separates the spiral conductor and the pair of external electrodes from each other. And the connection conductor is arranged in the groove provided in the core, and the center of the end face of the core is arranged.
In the vicinity, connect the connection conductor and the external electrode
It is characterized by having done.

The invention of claim 2 of the present application is characterized in that, in the chip coil of claim 1, the core is made of ferrite .

According to a third aspect of the present invention, in the chip coil according to the first aspect, the core is made of an insulator .

According to a fourth aspect of the present invention, in the chip coil according to the first aspect, the shape of the core is a prismatic shape .

According to a fifth aspect of the present invention, in the chip coil according to the first aspect, the core has a circular shape .

According to a sixth aspect of the present invention, in the chip coil according to the first aspect, the external electrodes are burned with a conductive paste.
It is characterized in by being configured with come.

The invention according to claim 7 of the present application is the chip coil according to claim 1, characterized in that the external electrodes are formed by plating .

[0016]

According to the inventions of claims 1 to 7 having the above characteristics, the eddy current generated in the cap-shaped external electrode is suppressed by disposing the connecting conductors in the grooves at both ends of the core. ing. For this reason, the Q of the chip coil and the inductance are prevented from being lowered and variations.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a chip coil according to the first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the chip coil of this embodiment includes a core 7, which will be described later, a spiral conductor 4, a cap-shaped external electrode 3a,
As in the conventional example, 3b are provided respectively.
The core 7 is composed of a ferrite core 7a or an insulator 7b, and conductor paths 8a and 8b are formed on the outer peripheral surfaces on both sides thereof. As shown in the sectional view of FIG. 2 and the perspective view of FIG.
Reference numerals a and 8b are grooves that extend from the cylindrical outer peripheral surface of the core 7 to approximately the center of the end surface. The conductor paths 8a and 8b are provided with connecting conductors 9a and 9b for connecting the spiral conductor 4 fixed to the outer peripheral surface of the core 7 and the external electrodes 3a and 3b.
b is provided. By connecting both ends of the spiral conductor 4 by the external electrodes 3a and 3b at the electrically most distant positions in this way, magnetic loss in the external electrodes 3a and 3b is prevented.

Further, as shown in FIGS. 1 and 2, the left end portion 4a and the right end portion 4b of the spiral conductor 4 are electrically connected to each other substantially at the centers of the end faces of the external electrodes 3a and 3b through the connecting conductors 9a and 9b. is doing. Therefore, no matter which part of the external electrodes 3a, 3b is soldered to the circuit board, the electrical connection between the end of the spiral conductor 4 and the external electrodes 3a, 3b is almost electrically the same, and Q and inductance are reduced. Can be suppressed.

The chip coil of the present invention is not limited to the above embodiment, but can be variously modified within the scope of the gist thereof. For example, instead of using a metal molded product as the external electrodes 3a and 3b, a part of the winding wire may be used, or a conductive paste may be baked or plated to form the electrodes. Further, the spiral conductor 4 may be replaced with the winding 2, and the connecting conductors 9a and 9b may be replaced with copper wires and the same effect can be obtained. Further, it goes without saying that the core 7 may be not only the columnar shape shown in FIG. 3 but also the prismatic shape.

[0020]

As described above in detail, according to the inventions of claims 1 to 7 of the present application, the end of the spiral conductor is substantially centered on the end face of the external electrode through the connecting electrode provided in the groove of the core. The effect of being able to reduce the Q and the inductance of the chip coil and to reduce the variation is further obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a chip coil according to a first embodiment of the present invention, in which mold resin and external electrodes are partly cut away.

FIG. 2 is a sectional view showing the structure of the chip coil of the first embodiment.

FIG. 3 is a perspective view showing the shape of a ferrite core or an insulator used in the chip coil of the first embodiment.

FIG. 4 shows a structure of a conventional chip coil (1),
It is the perspective view which notched the mold resin.

FIG. 5 shows a structure of a conventional chip coil (2),
It is a perspective view which notched a part of mold resin and an external electrode.

FIG. 6 is a perspective view showing a shape of a ferrite core or an insulator used in a conventional chip coil.

[Explanation of symbols]

7 core 1a, 7a Ferrite core 1b, 7b insulator 2 windings 3a, 3b External electrode 4 spiral conductor 4a left end 4b right end 9a, 9b connection conductor 5 Mold resin 8a, 8b conductor track

   ─────────────────────────────────────────────────── ─── Continued front page       (56) References JP-A-62-286211 (JP, A)                 JP-A-3-203205 (JP, A)                 JP 57-73915 (JP, A)                 JP-A-63-51609 (JP, A)                 Actual exploitation Sho 57-66514 (JP, U)                 Actual Development Sho 61-144616 (JP, U)                 55-179008 (JP, U)                 58-56424 (JP, U)

Claims (7)

(57) [Claims] And 1. A core groove at both ends is provided, comprising a winding which is wound on the core, and a pair of cap-shaped external electrodes provided at both ends of the core, the groove, From the outer peripheral surface of the core to near the center of the end surface
The winding has a spiral conductor spirally wound around the core and a connecting conductor connected to the external electrode, and the spiral conductor and the pair The external electrodes are arranged separately from each other, and the connecting conductor is arranged in the groove provided in the core, near the center of the end face of the core.
In the chip coil , the connection conductor and the external electrode are connected to each other . 2. The chip coil according to claim 1, wherein the core is made of ferrite. 3. The chip coil according to claim 1, wherein the core is made of an insulator. 4. The chip coil according to claim 1, wherein the core has a prismatic shape. 5. The chip coil according to claim 1, wherein the core has a circular shape. 6. The chip coil according to claim 1, wherein the external electrode is formed by baking a conductive paste. 7. The external electrode is formed by plating.
The chip coil according to claim 1, which is characterized in that.