JPS6223065Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to the structure of a chip-type inductor that is surface-connected to a printed circuit board, etc., and is easy to manufacture.
It relates to a structure that provides a highly reliable connection when attached to a printed circuit board, etc.

As a conventional chip-type inductor, as shown in FIG. 1, a drum core is provided with rectangular ribs 2 at both ends of a winding part 1, and electrodes 3 are formed by baking silver paste on the sides of the ribs 2. There is one in which the end of a coil (not shown) is wound around the electrode 3 and connected to the electrode 3 with solder.

However, if the electrode 3 is formed only on one plane, connection failure may occur during soldering to incorporate the chip inductor into a printed circuit board, etc., resulting in a lack of reliability. It was necessary to print and bake silver paste to form electrodes on multiple surfaces. but,
The workability of forming electrodes is poor, and the presence of metal in the magnetic circuit of inductors in particular causes deterioration of inductance and Q, and it is generally difficult to form electrodes that avoid this for chip inductors whose dimensions are extremely small. It was hot.

For this reason, as shown in FIG. 2, there is a device in which a thin metal plate is processed to have an L-shaped cross section, and this metal plate is adhered to the collar 2 of the drum core to form the electrode 4. However, in this case as well, the forming of the metal plate,
Processing such as cutting was complicated, and when adhering to the drum core, the adhesive surface to the printed circuit board had to be formed flat, resulting in poor processability. Moreover, the electrode 4 is
In order to solder it to a printed circuit board or the like, it must be attached to the outer periphery of the drum core, but since the metal plate is thin, it is difficult to prevent it from affecting the magnetic flux. Furthermore, the coil wire connected to the electrode 4 sometimes breaks due to burrs during processing of the metal plate.

The present invention eliminates the drawbacks of conventional chip inductors as described above, and provides a chip inductor that has an electrode structure that is easy to process, easy to manufacture, and provides a highly reliable connection. be.

That is, the chip-type inductor according to the present invention uses a metal wire with a rectangular cross section as an electrode, and at least one side of the collar of the core member has a collar at both ends of the winding portion forming a flat part. , and two longitudinally adjacent surfaces of a metal wire preferably having a substantially square cross section are bonded to the cutout portion provided between the flat portion and the outer end surface of the brim to form an electrode.
It is characterized in that a coil wound around the winding part is connected to the electrode.

The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view of a core member of a chip-type inductor showing an embodiment of the present invention, with one of its electrode portions being exploded. That is, the core member is made of magnetic material such as ferrite,
A rectangular collar 12 is provided at both ends of the winding portion 11. The collar 12 does not necessarily have to be rectangular, but may have any shape that has a flat contact surface with a substrate such as a printed circuit board into which the chip inductor is incorporated. The collar 12 is provided with a flat part 12a for opposing contact with a printed circuit board, etc., and a cutout part 13 in which a part of the outer end surface 12b is cut out along the flat surface, and the cross section is a cut with a substantially right angle. .
Reference numeral 14 denotes a metal wire with a substantially square cross section, which is cut into a predetermined length, and adhesive is applied to two longitudinally adjacent surfaces of the wire, which is then fitted into the cutout 13 and fixed to form the electrode 15. do.

At this time, if the entire surface of the wire rod with a square cross section is soldered, the solder on the two adjacent sides is mechanically removed and cut, and the removed surfaces are glued to the cutout part 13 of the core member. In addition to preventing oxidation of the wire surface and achieving strong adhesion, soldering can be performed without the troublesome work of applying solder plating by solder dipping or plating after the electrode is provided on the core member.

The core member on which the electrode 15 is formed has a winding portion 11
A coil is wound around the electrode 15, and the end thereof is soldered to the electrode 15. The electrodes can be made of ordinary conductive materials that can be soldered, but if a material with low magnetic permeability such as copper is used, the electrodes can be designed to be located outside the magnetic circuit, thereby preventing deterioration of inductance and Q. be able to. FIG. 4 is a cross-sectional view of an example of such a case, and the magnetic flux is
The magnetic circuit is constructed without passing through the On the other hand, in the conventional example, since the electrode part of this embodiment also has a magnetic material of the core member such as ferrite with high magnetic permeability, the magnetic flux passes through this part and passes through the thin electrode material, causing eddy current loss. This lowers the Q of the inductor. In addition, in Figure 4, 1
6 is a coil.

FIG. 5 is a side view showing another embodiment of the present invention. In this embodiment, the electrode 15 is formed of a wire rod having a substantially square cross section, and the cutout portion 13
The corner with the end surface 12b is chamfered so that the taper 12
c has been applied. When such a taper 12c is provided, an excess portion of the adhesive for fixing the electrode 15 to the collar 12 is accommodated in the gap created between the taper 12c and the electrode 15, thereby preventing the adhesive from extruding. Further, in the embodiment shown in FIG. 5, a step having a distance h is provided between the contact surface 15a of the electrode 15 with a printed circuit board or the like and the lower surface 12a of the core member facing the printed circuit board. In this way, when the chip inductor is incorporated into a printed circuit board, the printed circuit board and core member do not come into direct contact and the influence of the conductor of the printed circuit board can be avoided, resulting in changes in coil inductance and deterioration of Q. can be prevented. Moreover, in this case, since the coil can be connected to the bottom surface of the core member without being disposed on the bottom surface of the electrode 15, disconnection when placed on a printed circuit board can be significantly reduced.

As described above, in the chip-type inductor according to the present invention, a cutout portion is provided between the surface of the rib of the core member facing the printed circuit board and the outer end surface of the rib, and the cutout portion has a concave portion whose cross section is approximately at right angles. In addition, since the electrode is made by gluing two longitudinally adjacent surfaces of a metal wire with a rectangular cross section, preferably a substantially square cross section, the electrode can be easily obtained by simply cutting the square wire, and is a special material. No molding required. Further, positioning of the electrodes during adhesion is simple, and manufacturing is easy.

In addition, the flatness of the electrode required for connection to the printed circuit board can be easily obtained, and the remaining two sides of the electrode that are not bonded to the core member can be soldered to the printed circuit board, etc., improving reliability. Connection with high conductors such as printed circuit boards can be obtained.

Further, since the electrode uses a wire rod having a substantially square cross section, deterioration of inductance and Q can be prevented. Furthermore, the wire material forming the electrode has no burrs, and its corners can be easily rounded or tapered, so that breakage of the coil wire material can be prevented.

As described above, the present invention is highly practical and useful.

[Brief explanation of drawings]

Figures 1 and 2 are perspective views of a conventional chip inductor with the windings removed, respectively.
The figure is a partially exploded perspective view of one embodiment of the chip inductor according to the present invention, FIG. 4 is an explanatory diagram of the magnetic flux distribution in the embodiment of FIG. 3, and FIG. 5 is another embodiment of the chip inductor according to the present invention. FIG. DESCRIPTION OF SYMBOLS 11...Winding part, 12...Brim, 13...Removal part, 15...Electrode, 16...Coil.

Claims (1)

[Claims for Utility Model Registration] (1) At least one side of each rib of a core member having ribs at both ends of the winding portion is formed as a flat portion, and the flat portion and the outer side of each rib are A chip-shaped inductor in which two longitudinally adjacent surfaces of a metal wire having a rectangular cross section are bonded to a cutout portion provided over the end face to form an electrode, and a coil wound around the winding portion is connected to the electrode. . (2) The chip-shaped inductor according to claim 1, wherein at least one of the two adjacent surfaces of the electrodes to be connected to a conductive portion of a printed circuit board or the like protrudes from the collar of the core member. (3) The chip-shaped inductor according to claim 1 or 2, wherein the cut-out portion of the core member is tapered at the corners.