JPS6225856Y2 - - 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. There is one in which the end of a coil (not shown) wound around 1 is connected to an 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. However, it was 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.The electrodes that avoid this are generally extremely small with dimensions of less than 4 mm on each side. This was difficult with chip-type inductors. For this purpose, a thin metal plate is processed so that its cross section is L-shaped, as shown in Figure 2.
There is one in which the electrode 4 is formed by bonding this metal plate to the collar 2 of the drum core. However, in this case as well, processing such as forming and cutting the minute metal plates is complicated.
For adhesion to the drum core, the adhesion surface to the printed circuit board had to be formed flat, and processability was not good. 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.

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.

In other words, the chip-type inductor according to the present invention uses a metal wire with a square cross section as an electrode, and has a core member with flanges at both ends of the winding portion, and a protrusion located inside the periphery of the core member on the outer end surface of one of the flanges. A part of the longitudinal surface of a rod-shaped metal wire with a rectangular cross section is in contact with the side surface of the protrusion, and another longitudinal surface is adhered to the outer end surface to form an electrode. The coil wound around the winding portion is connected to the electrode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the chip-type inductor of the present invention will be explained below with reference to FIGS. 3 and 4, which are perspective views.

First, in FIG. 3, the core member is made of a magnetic material such as ferrite, and has a circular upper rib 5 and a lower rib 6 that sandwich the winding part, and the outer end surface 7 of the lower rib, that is, a printed circuit board, etc. A circular protrusion 8 is provided at the center of the surface facing the . A rod-shaped metal wire with a rectangular cross section is cut to a predetermined length, and an adhesive is applied to one longitudinal surface to form an electrode 9 on the outer end surface 7.
The longitudinal end thereof protrudes from the outer end surface 7. The protrusion 8 has the role of determining the bonding position of the electrode 9, and the outer end surface 7 of the electrode 9
A part of the longitudinal surface adjacent to the surface adhered to is brought into contact with the side surface of the protrusion 8. Of course, a part of the surface of the electrode 9 may be fixed to the side surface of the protrusion 8 by applying an adhesive to this contact portion.

When forming the electrode 9, a rod-shaped metal wire with a rectangular cross section is soldered on the entire surface, the solder on the adhesive surface is mechanically removed and cut, and the removed surface is attached to the outer end surface of the core member. By adhering to 7, oxidation of the surface of the wire can be prevented and strong adhesion can be achieved, and the troublesome work of soldering by solder dipping or plating after providing the electrode 9 on the core member is not required.

A coil 10 is wound around the core member on which the electrode 9 is formed, and the end 11 of the coil 10 is drawn out and soldered to the electrode 9. In this embodiment, the ends of the electrodes 9 are made to protrude from the outer end surface 9, so if the ends 11 are twisted and then soldered, the connection will be very reliable and the work will be easy.

FIG. 4 shows another embodiment of the chip-type inductor of the present invention, in which the same parts as in FIG. 3 are given the same reference numerals.

The difference from FIG. 3 is that the shape of the protrusion 12 provided on the outer end surface 7 of the lower brim is square. If the shape of the protrusion 12 is square, the directionality in the longitudinal direction is defined when forming the electrode 9, which is convenient when the directionality needs to be defined. Furthermore, when adhesive is applied to the side surface of the protrusion 12, the contact area with the electrode 9 is wider than in the case shown in FIG. Can be done. By the way, the electrode 9 in the embodiment of the present invention may be made of an ordinary solderable conductive material, but if a material with low magnetic permeability such as copper is used, the electrode may be designed to be located outside the magnetic circuit. Therefore, deterioration of inductance and Q can be prevented. FIG. 5 is a diagram illustrating such a case in the embodiment of FIG. 4, in which the magnetic flux shown by the dotted line does not pass through the electrode 9, so that a magnetic circuit is constructed. 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 faces directly to the printed circuit board. Therefore, if the wiring conductor of the printed circuit board touches between the two ribs, the magnetic circuit In contrast, in the inductor of the present invention, the inductor is vertical with respect to the printed circuit board, and the lower collar 6 with high magnetic permeability is located between the coil 10 and the printed circuit board 13. Therefore, even if there is a wiring conductor, the magnetic circuit is unlikely to be disturbed. In addition, it is possible to apply adhesive 14 to the protruding portion 12 of the lower brim to attach a chip-type inductor to the printed circuit board 13, and then connect it to the solder 15 and wiring conductor 16, making it convenient for integration into a circuit. be. Furthermore, since the electrode 9 has a rectangular cross section, the adhesive that adheres the electrode 9 to the core may flow and cover the electrode, unlike when the electrode 9 has a round cross section. There is no possibility that the adhesive that adheres to the printed circuit board will flow down to the printed circuit board and reduce the reliability of soldering. In the chip-type inductor shown in FIG. 5, the horizontal surface of the protruding portion 12 is located above the horizontal surface on the lower side of the electrode 9, so that the printed circuit board 13 and the lower rib 6 of the core member do not come into direct contact. It is designed to avoid the influence of the conductor of the printed circuit board and prevent changes in inductance and deterioration of Q.

In the embodiment of the present invention, the electrode 9 protrudes from the outer end surface 7 and is designed to wrap around the end 11 of the coil, but this is not an essential condition of the present invention, and the electrode 9 should not protrude from the outer end surface 7. However, the purpose of the present invention can be fully achieved. Furthermore, the shapes of the protruding portions 8 and 12 do not need to be limited to those in the embodiment, and may not necessarily be present if another jig for determining the position of the electrode 9 is used.

As described above, in the chip-type inductor according to the present invention, the longitudinal surface of a rod-shaped metal wire with a rectangular cross section is glued to the lower rib of the core member to form an electrode. It can be easily obtained by simply molding, and no special molding is required. In addition, the flatness of the electrode required for connection to the printed circuit board can be easily obtained, and the two sides of the electrode that are not glued to the other parts allow for soldering to the coil lead wire and printed circuit board, etc., resulting in reliability. Connection with conductors such as printed circuit boards with high resistance 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]

1 and 2 are perspective views showing a conventional chip inductor with the windings removed, and FIGS. 3 and 4 are perspective views showing an embodiment of the chip inductor of the present invention, respectively. FIG. 5 is an explanatory diagram of the magnetic flux distribution of the chip-type inductor of the present invention. 5: Upper collar, 6: Lower collar, 7: Outer end surface of lower collar 6, 8, 12: Projection, 9: Electrode, 10: Coil, 11: End of coil 10, 13: Printed circuit board, 14: Adhesion agent, 15: solder, 16: wiring conductor.

Claims (1)

[Scope of utility model registration request] A core member with flanges at both ends of the winding part has a protrusion on the outer end surface of one of the flanges, which is located inside the periphery of the core member. , a chip-type inductor formed by bonding another longitudinal surface to the outer end surface while in contact with the side surface of the protrusion to form an electrode, and connecting a coil wound around the winding portion to the electrode. .