JPS6325703Y2 - - 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.
The present invention relates to a structure that provides a highly reliable connection when attached to a printed circuit board, etc., and whose characteristics are not easily affected by the conductors of the printed circuit board.

As shown in FIG. 1, a conventional chip-type inductor has a drum core with rectangular ribs 2 at both ends of a winding portion 1. Silver paste is baked on the lower surface of the rib 2 to form an electrode 3. In some cases, the end of a coil (not shown) wound around 1 is also connected to the electrode 3 with solder.

However, if the electrode 3 is formed only on one plane, a 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 also necessary to print and bake silver paste to form electrodes on multiple surfaces. However, 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. Electrodes that avoid this are generally formed with extremely small dimensions of less than 5 mm on each side. This was difficult with chip-type inductors.

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, processing such as forming and cutting a minute metal plate is complicated, and the adhesion surface to the printed circuit board must be made flat to adhere to the drum core, resulting in poor workability. Further, the electrode 4 must be attached to the outer periphery of the drum core in order to solder the chip-shaped inductor to a printed circuit board or the like, but since the metal plate is thin, it is difficult to prevent its influence on 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 the conventional chip-type inductor as described above, has good processability, is easy to manufacture, and provides a highly reliable connection. The present invention provides a chip-type inductor having a structure in which the influence of eddy current loss due to conductors is small.

That is, the chip-type inductor according to the present invention uses a metal wire with a rectangular cross section as an electrode, and a core member has ribs at both ends of the winding portion, and one rib of the core member has ribs on one side of the rib. Two longitudinally adjacent surfaces of a metal wire, preferably having a substantially square cross section, are bonded to the cutout portion provided from the two opposing objects to the adjacent outer end surfaces to form an electrode, and the wire is wound around the winding portion. The device is characterized in that a coil 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, and FIG. 4 is a bottom view thereof.

The core member is made of magnetic material such as ferrite,
The winding portion 11 is narrowed to include an upper rib 12 and a lower rib 13 in the shape of a rectangular plate. The brim 12, 13 does not necessarily have to be rectangular, and may be of any shape, but
In the case of a rectangular shape, it is easy to obtain directionality when automatically incorporating it into a printed circuit board. The lower collar 13 has a cutout portion 16 in which a portion of the outer end surface 13a that faces and comes into contact with a printed circuit board, etc. and the side surface 13b adjacent thereto is cut along both edges of the collar, and the cutout portion 16 has a substantially right-angled cut in cross section. It is provided. Reference numeral 14 is a metal wire having a substantially square cross section, which is cut into a predetermined length, and adhesive is applied to two longitudinally adjacent sides of the wire to form a cutout portion 16.
The electrode 14 is formed by fitting and fixing the electrode. At this time, the entire surface of the wire with a rectangular 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 16 of the core member. This method prevents oxidation of the wire surface and provides strong adhesion, and does not require the troublesome work of applying solder plating by solder dipping or plating after the electrodes are provided on the core member.

The core member on which the electrode 14 is formed has a winding portion 11
A coil is wound around the electrode 14, the end thereof is pulled out, passed through a groove 15 provided on the side surface of the lower collar, and guided from the side surface of the electrode 14 to the lower surface and soldered thereto. The electrode 14 may be made of an ordinary conductive material that can be soldered, but if a material with low magnetic permeability such as copper is used, the electrode can be designed to be located outside the magnetic circuit, thereby preventing deterioration of inductance and Q. It can be prevented. FIG. 5 is a diagram explaining such a case, in which a magnetic circuit is constructed without the magnetic flux passing through the electrode 14. On the other hand, in the conventional example, since there is a magnetic material of the core member such as ferrite with high magnetic permeability in the electrode part of this example, the magnetic flux also passes through this part, passes through the thin electrode material, and vortexes. The Q of the inductor was lowered due to current loss. Furthermore, in the conventional example, since the chip-type inductor is placed horizontally, the coil wound around the winding part 1 directly faces the printed circuit board. In contrast, in the present invention, the inductor is vertical to the printed circuit board, and the lower collar 13 with high magnetic permeability is provided between the coil 17 and the printed circuit board 19. Therefore, even if there is a temporary wiring conductor, the magnetic circuit is less likely to be disturbed. In addition, adhesive 18 is applied to the bottom surface of the lower flange 13 to attach the chip inductor to the printed circuit board 20, and then the electrode 1 is attached with the solder 21.
4 and the wiring conductor 20,
It is also convenient for integration into circuits.

In the chip inductor shown in FIG. 5, the electrode 14 slightly protrudes from the bottom surface 13a of the lower flange 13.
The printed circuit board 19 and the lower rib 13 of the core member are prevented from coming into direct contact, thereby avoiding the influence of the conductor of the printed circuit board and preventing changes in inductance and deterioration of Q.

By chamfering the electrode 14, the gap between the chamfer and the core member can contain the excess adhesive that fixes the electrode 14 to the core member, preventing the adhesive from spilling out, and also preventing the coil lead from breaking. It can be prevented.

As described above, in the chip-shaped inductor according to the present invention, a cut-out portion is provided over the side surface and outer end surface of the lower brim of the core member, and the cut-out portion, which has a substantially right-angled recess in cross section, preferably has a rectangular cross section. Since the electrode is made by bonding two longitudinally adjacent surfaces of a square metal wire, the electrode can be easily obtained by simply cutting the square wire, and no special shaping is required. In addition, 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 allow soldering to the coil lead wire and printed circuit board, etc. , a highly reliable connection with a conductor such as a printed circuit board can be obtained.
Furthermore, since the electrode has a rectangular cross section, deterioration of inductance and Q can be prevented. Also, because of the vertical structure, there is little influence from conductors such as printed circuit boards. It has the advantage that it can be easily integrated into a printed circuit board, etc.

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

[Brief explanation of the drawing]

Figures 1 and 2 are perspective views of a conventional chip inductor with the windings removed, respectively.
4 is a bottom view of the embodiment of FIG. 3, and FIG. 5 is an explanatory diagram of the magnetic flux distribution of the chip inductor of the present invention. DESCRIPTION OF SYMBOLS 11... Winding part, 12... Upper rib, 13... Lower rib, 14... Electrode, 16... Excision part, 17...
coil.

Claims (1)

[Claims for Utility Model Registration] (1) A core member having rectangular plate-shaped ribs at both ends of the winding portion, one rib of which is provided with a groove for guiding the end of the coil to the electrode, and the ribs are opposite to each other. An electrode is formed by adhering two longitudinally adjacent surfaces of a metal wire made of a material with low magnetic permeability and having a substantially square cross section to the cut sections whose cross sections are perpendicular to each other from the two side surfaces to the outer end surface. . A chip-type inductor for surface mounting, in which an end of a coil wound around the winding portion is connected to the electrode through the groove. (2) The chip-type inductor according to claim 1, wherein at least one of 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.