JP2003318044A - Small-sized surface-mount coil and circuit board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a small-sized surface-mount coil so that the coil may not be disconnected by impacts, etc., when the coil comes into contact with another electronic component or is mounted, and to reduce the size of a circuit board formed by using a chip electronic component by increasing the mounting density on the board. <P>SOLUTION: The small-sized surface-mount coil is composed of a core wound with a winding, a base holding the core, and electrode terminals buried in the base. The base is provided with electrode terminals each composed of a surface- mount terminal and a binding terminal, a hollow section formed by hollowing out the central part of the base, and guide grooves which guide the terminals of the winding from the hollow section to the binding terminals on its bottom face. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small surface mount coil used in electronic equipment and a circuit board using the same.

[0002]

2. Description of the Related Art A conventional small surface mount coil is shown in FIG.
4, in the coil 20, a drum-shaped core 22 around which a winding wire 23 is wound is fixed to a base 25 having a plurality of surface mounting external terminals 27 and a plurality of barbed terminals 26. . However, the external terminal 27 and the barbed terminal 26 are integrated inside the base 25. Winding terminal 2 of coil 20
4 is drawn along the upper surface of the base toward the barbed terminal 26 protruding to the side surface, and is entangled.

As described above, since the winding end 24 of the coil 20 is drawn around the upper surface of the base and is entangled with the winding end 24, the coil 20 is disconnected due to contact with other electronic components and impact during mounting. There was a problem.

[0004]

In view of the above problems, the small-sized surface mount coil of the present invention has a structure that does not break due to contact with other electronic components, impact during mounting, and the like. It is intended to increase the packaging density of a circuit board formed by using a mold electronic component and to reduce the size thereof.

[0005]

SUMMARY OF THE INVENTION The present invention is a small surface mount coil including a wound core, a base for holding the core, and electrode terminals embedded in the base. An electrode terminal including a terminal is provided, a hollow portion is provided by hollowing out the central portion of the base, and a guide groove for guiding the end of the winding from the hollow portion toward the twisted terminal is provided on the bottom surface of the base. Then, in combination with a plurality of chip-type electronic components that form an electric circuit, a plurality of chip-type electronic components are internally provided on the circuit board and inside the hollow portion of the bottom surface thereof.

[0006]

The small surface mount coil according to the present invention is a small surface mount coil including a wound core, a base holding the core, and electrode terminals embedded in the base. The base is equipped with electrode terminals consisting of surface mount terminals and barbed terminals.A hollow is formed by hollowing out the center of the base, and the end of the winding is routed from the hollow to the barbed terminal in the bottom of the base. With the guide groove provided, the end of the winding is drawn out from the hollow portion of the base and entangled with the barbed terminal through the guide groove on the bottom surface of the base. Therefore, the end of the winding can be connected to the stripping terminal without being entangled in the state where the upper surface of the base is exposed, so that it is possible to prevent disconnection due to contact with other components or work. Since a plurality of chip-type electronic components can be internally provided in the hollow portion of the bottom surface of the base by hollowing out the central portion of the base of the small surface mounting coil, the component occupying area on the circuit board is limited to the coil, The substrate can be downsized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A small surface mount coil which is an embodiment of the present invention will be described below with reference to FIGS. Figure 1
1A is a perspective view seen from the upper surface, and FIG. 1B is a perspective view seen from the bottom surface side. As shown in FIGS. 1 (a) and 1 (b), 1 is a coil, 2 is a core, 3 is a winding wire, 4 is a winding terminal, 5 is a base, and 6 is a winding terminal for winding the winding terminal 4. ,
Reference numeral 7 is a surface mounting external terminal for connecting an external circuit. The coil 1 is formed by winding a winding 3 around a drum-shaped drum core 2 with a conductor coated with an insulating coating such as a urethane coating, and fixing the winding 3 to an upper surface of a base 5 with an adhesive or the like.
The drum core 2 is shaped like a drum using a ferrite magnetic material. The base 5 is formed by molding a heat resistant insulating resin in a shape having a hollow portion 8 having a quadrangular outer shape and a hollowed central portion. A guide groove 9 for guiding the winding end 4 is provided on the bottom surface of the base from the hollow portion 8 toward the twisted terminal 6. The plurality of external terminals 5 and the plurality of barbed terminals 6 are integrated inside the base. In this way, the winding end 4 of the coil 1 is drawn out from the hollow portion 8 on the bottom surface of the base, entangled with the barbed terminal 6 through the guide groove 9 provided on the bottom surface of the base, and electrically connected by soldering or the like. Connected.

Next, a small surface mount coil which is another embodiment is shown in FIG. 2A is a combined sectional view, and FIG. 2B is a bottom view thereof. This small surface-mount coil has a stepped portion in the hollow portion of the base, the winding portion is housed in the base, and the winding portion is prevented from being affected by the outside, so that it has a low profile. The same parts as those in FIG. 1 are designated by the same reference numerals. As shown in FIGS. 2 (a) and 2 (b), the hollow portion 8 hollowed out in the central portion of the base has a large hollow portion 8a on the upper surface side.
A step formed by narrowing the hollow portion 8b on the bottom surface side is provided.
The bottom surface of the base is provided with respective guide grooves 9 corresponding to the barbed terminals from the hollow portion 8b toward the barbed terminals 6. The plurality of external terminals 7 and the plurality of barbed terminals 6 are integrated inside the base 5.

The core 2 around which the winding 3 is wound is inserted through the hollow portion 8a on the upper surface side and fixed by an adhesive or the like at the step portion of the hollow portion 8b on the bottom surface side. The winding terminal 4 of the coil is drawn out from the hollow portion 8b on the bottom surface side and is provided with a guide groove 9 provided on the bottom surface of the base.
Is entangled with the terminal 6 and soldered to be electrically connected. As described above, the coil winding 3 and the winding terminal 4 are drawn out from the hollow portion 8 on the bottom surface of the base, and are entangled with the barbed terminal 6 through the guide groove 9, so that other parts or the like come into contact with each other. Therefore, it is possible to prevent disconnection of the winding portion and the winding end.

Next, FIG. 3 shows a circuit (a) using the small surface mount coil and the chip type electronic component of the present invention and a model diagram (b) mounted on a substrate. As shown in FIG. 3A, as a circuit, a tuning IC is formed by using a coil L (L1, L2, L3) and a capacitor C (C1, C2, C3), and a control IC for controlling the tuning circuit is formed. This is a general circuit used. Such a circuit can be used as a unit forming a frequency selection circuit for oscillation or reception. Figure 3
FIG. 3B shows a model diagram mounted on the substrate 10 according to the circuit of FIG. As shown in FIG. 3B, the circuit board has an area of only the small surface mount coil 1 of the present invention and the external connection terminal T on the board 10, and controls a plurality of capacitors forming a tuning circuit and a circuit. The IC is housed in the hollow portion 8 on the bottom surface of the base of the small surface mount coil.

The dimensions of an embodiment of a circuit board using the small surface mount coil of the present invention are shown below. The size of the small surface mount coil of the present invention is 10.8 mm in length and 10.8 m in width.
m, height 3 mm (hollow part vertical 7 mm x width 7 mm).
The capacitors are three 1.6 mm x 0.8 mm chip type capacitors C, the control IC is 3 mm x 2.3 mm,
The height is 0.5 mm, and when this is used for one circuit board, the size of the board can be set to 15 mm (vertical) × 15 mm (horizontal). When the conventional small surface-mount coil is used, the size of the substrate is 16 mm × horizontal 16 mm because three chip capacitors and the control IC are arranged around the small surface-mount coil. The layout is shown in FIG. As described above, the circuit board using the small surface mount coil of the present invention (FIG. 3B) has an area ratio of 0. 5 as compared with the circuit board using the conventional small surface mount coil (FIG. 5).
It can be reduced to 76 times. The scales of FIG. 3B and FIG. 5 are the same.

The embodiments of the small surface mount coil and the circuit board using the same according to the present invention have been described above, but the present invention is not limited to these embodiments. For example, a drum-shaped drum core is used as the coil, but a bobbin molded of resin may be used, or a toroidal core used for a noise filter or the like may be used. Further, the shape of the base is not limited to a quadrangle, but may be a polygon or a circle.

[0013]

As described above, in the small surface mount coil of the present invention and the circuit board using the same, a hollow portion is provided by hollowing out the central portion of the base, and the hollow portion is provided on the bottom surface of the base as a twisted terminal. A guide groove for guiding the end of the winding is provided toward the end of the winding, and the end of the winding is drawn out from inside the hollow portion of the bottom surface of the base and passed through the guide groove to be entangled with the spine terminal. Therefore, the end of the winding can be connected to the stripping terminal without wiring in the state where the upper surface of the base is exposed, so that it is possible to prevent disconnection due to contact with other components or work. Since the chip type electronic component is arranged in the hollow portion of the bottom surface of the base of the small surface mounting coil, the circuit board can be miniaturized by setting the component occupying area of the circuit board only as the outer area of the coil.

[Brief description of drawings]

FIG. 1A is a perspective view of a small surface mount coil according to an embodiment of the present invention as viewed from above and FIG. 1B is a perspective view as viewed from below.

FIG. 2 is a sectional view (a) and a bottom view (b) of a combination of another embodiment of the present invention.

FIG. 3 is a circuit (a) using the small surface mount coil of the present invention.
And its circuit board model diagram.

FIG. 4 is a perspective view (a) and a bottom view (b) of a conventional small surface mount coil.

FIG. 5 is a circuit board using a conventional small surface mount coil.

[Explanation of symbols]

1 coil 2 cores 3 windings 4 winding terminals 5 base 6 Charging terminal 7 surface mount terminals 8 hollow 9 guide groove

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomio Mizutani             Toko, 18 Gomigaya, Oji, Tsurugashima City, Saitama Prefecture             Saitama Office Co., Ltd. F-term (reference) 5E043 EA05 EB02                 5E070 AA01 EA02 EB01

Claims (3)

[Claims] 1. A small surface mount coil comprising a wound core, a base for holding the core, and an electrode terminal embedded in the base, wherein the electrode terminal comprises a surface mount terminal and a twist terminal. A small surface mount coil characterized in that the base is provided with a hollow portion having a hollowed-out central portion, and a guide groove for leading the end of the winding from the hollow portion to the twisted terminal is provided on the bottom surface of the base. . 2. The small surface-mount coil according to claim 1, wherein the hollow portion of the base is provided with a step by making the top surface side large and the bottom surface side small. 3. A circuit board comprising an electric circuit using the small surface-mounting coil according to claim 2 and a plurality of chip-type electronic parts, wherein the chip-type electronic part is arranged and mounted in the hollow portion of the bottom surface of the small surface-mounting coil. A circuit board using a small surface mount coil.