JPH0410723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to inductance components used in various electronic devices.

Conventional configurations and their problems In recent years, various electronic devices have been rapidly miniaturized due to the increased density and multifunctionality of semiconductor integrated circuits and the appearance of chip resistors and chip capacitors.
These leadless chip components can be mounted on wiring boards in various ways using reflow soldering, allowing for high-density mounting. Under these circumstances, there is a strong demand for leadless and chip components for inductance components.

A conventional fixed inductance component will be described below with reference to the drawings.

FIG. 1 shows an example of a conventional fixed inductor.
In the figure, 1 is a drum-shaped ferrite core, 2 is a wire wound around the ferrite core to obtain the required inductance, and 3 is a lead terminal for drawing out the coil, one end of which is fixed to the center of the brim at both ends of the ferrite core. The electrical connection is made by wrapping the end of the coil 2 around the lead terminal 3 several times and soldering it. Reference numeral 4 denotes an exterior coating that covers the entire coil to protect the internal structure, and is generally made of epoxy resin or the like.

If a metal plate terminal or a cap electrode terminal is used instead of the lead terminal 3 in order to realize a leadless chip component with the structure of the fixed inductance component configured as described above, a large Q decrease will occur, and the inductance component will not be used as an inductance component. The electrical performance of the device will be significantly degraded. Furthermore, other chip parts are becoming mainstream, and in consideration of automating the process of installing various chip parts by the user, it is desirable that the inductance part is not cylindrical but square like the other parts. In addition, in lead-type fixed inductance parts with a single magnetic core, a so-called open magnetic path is formed and large inductance cannot be obtained. Therefore, if high inductance is required, a cylindrical part is installed around the outer periphery of the coil magnetic core. Previous methods have included covering the product with a magnetic material or mixing a magnetic material into the outer coating resin, but the former requires a large shape, and the latter is not effective because it is not possible to mix a large amount of magnetic material to achieve fluidity. Nakatsuta.

OBJECTS OF THE INVENTION An object of the present invention is to provide a rectangular leadless, chip, inductor that has sufficient electrical performance and can be produced at low cost.

Structure of the Invention In the chip inductor of the present invention, a pair of metal plate terminals facing each other on the same plane have a tapered and narrow protrusion at their tips, and a drum core around which a wire is wound on the protrusion is attached to the central axis of the tip. is perpendicular to the metal plate terminal surface and straddles between the protrusions and fixed,
The end of the wire ring is connected to a metal plate terminal, and the entire body is covered with an exterior resin molded body, leaving the connection part of the metal plate terminal to an external circuit, thereby ensuring sufficient electrical performance. This makes it possible to produce chip-type inductance parts that are highly mass-producible.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows an inductance component in one embodiment of the present invention. In Figure 2, 5
is a drum core, 6 is a wire wound around the drum core to obtain the required inductance, 7 is a pair of metal plate terminals arranged facing each other on the same plane, 8
is a narrow protrusion provided at the tip of the metal plate terminal 7, and the drum core 5 is arranged so as to straddle the protrusion 8 and the central axis of the drum core 5 is perpendicular to the metal plate terminal surface. It's stuck. Reference numeral 9 indicates an electrical connection between the metal plate terminal 7 and the wire ring 6, and 10 indicates an exterior resin molded body, which protects the internal structure of the product and forms the outer shape of the product. Reference numeral 11 denotes an external connection terminal portion formed by drawing out the metal plate terminal 7 to the outside of the exterior resin molded body 10 and bending it along the outer shape of the product. Further, FIGS. 3a and 3b are views of the portion where the drum core 5 is fixed to the metal plate terminal protrusion 8 when viewed from the bottom side, and FIG. FIG. 3b shows a case where one protrusion 8 is provided on each of the opposing metal plate terminals 7.

Although this embodiment shows an example in which the external connection terminal portion 11 is bent so as to form a terminal from a portion of the side surface to a portion of the bottom surface of the exterior resin molded body 10, it is not necessarily limited to this shape. It goes without saying that it is not limited to this, but may instead be bent outward along a part of the side surface of the exterior resin molded body 10 on the same plane as the bottom surface.

In the inductance component of this embodiment configured as described above, the metal plate terminal 7 does not block the magnetic flux emitted from the drum core 5, and the area of the metal plate terminal 7 that directly contacts the drum core 5 is extremely small, so the Q is reduced. An inductance portion with a small amount of electric power and good electrical performance can be obtained. This is because the drum-shaped ferrite core has the property that the maximum magnetic flux is concentrated at the inner corner ends of the brim at both ends of the drum.
Also, the electrical connection part 9 and the external connection terminal part 11
Because the wire is wide, it is extremely easy to connect the wire leads using an automatic machine, and surface mounting on a printed circuit board is advantageous. In addition, the outer shape of the product is molded by the exterior resin molded body 10, so it can be easily formed into a square chip part shape, and it is also possible to have a large degree of freedom in designing the size and shape. In addition, with the structure according to the present invention, the metal plate terminal 7 can be supplied as a continuous terminal strip, and the drum core 5 can be fixed from the beginning of the production process. Since each process such as the winding process, wiring process, exterior molding process, and even external lead-out terminal processing process can be performed with the continuous terminal strip, production efficiency can be greatly improved. It is.

Another embodiment of the invention is shown in FIG. In the figure, 1
Reference numeral 2 denotes a protrusion provided on the outer part of the brim of the drum core 5. As a result, by fitting the protruding part 8 of the metal plate terminal 7 and the protruding part 12, it is possible to determine the fixing position of the drum core 5 on the metal plate terminal 7, which is useful for stabilizing the process during mass production. This has a great effect. Note that even in this case, it goes without saying that even one protrusion 8 is possible. In addition, thermosetting resins that can be transfer-formed or injection molded are generally used as exterior molding resins, but instead of inorganic additives added to thermosetting resin materials, magnetic oxide By adding these substances, the performance as an inductance component can be improved without deteriorating the characteristics as an exterior resin molded product. Specifically, by adding 70 to 80% by weight of a finely powdered ferrite material to an epoxy molding resin, the inductance value increases two to three times, and the ferrite-containing molding resin provides magnetic shielding properties for the inductance component. This magnetic shielding property has the effect of reducing the effects on other circuits due to mutual electromagnetic induction in chip components that are mounted in high density.
Combined with the effect of obtaining high inductance, the performance of inductance components can be significantly improved.

Effects of the Invention As is clear from the above description, the present invention provides a method for connecting a pair of metal plate terminals having protrusions at opposing ends on the same plane, straddling the protrusions of a pair of metal plate terminals, and centering the drum core with respect to the metal plate terminal surface. Since the structure is such that the axis is placed and fixed on the protrusion vertically, an inductance component with good electrical performance including a high Q value can be obtained, and the lead wire of the wire ring can be easily attached to an automatic machine. Very easy to connect. Further, by forming the metal plate terminal into a continuous terminal strip, each manufacturing process can be operated in a consistent process movement pattern, resulting in excellent mass productivity and low cost production. In addition, by mixing ferrite into the exterior molding resin, an inductance component with even further improved electrical performance can be obtained with the same structure and same production process, and it is also advantageous for surface mounting on printed circuit boards, so its industrial value is very large.

[Brief explanation of drawings]

FIG. 1 is a transparent perspective view showing an example of a conventional inductance component, FIG. 2 is a transparent perspective view showing an inductance component according to an embodiment of the present invention, and FIGS. 3a and 3b are metal plates of an inductance component according to the present invention. FIG. 4 is a perspective view showing an example of a terminal, and FIG. 4 is a perspective view showing another embodiment of the inductance component according to the present invention. 5...Drum core, 6...Wire ring, 7...Metal plate terminal, 8...Protrusion part, 10...Exterior resin molded body,
11...Terminal part for exterior connection, 12...Protrusion part.

Claims (1)

[Claims] 1 A pair of metal plate terminals facing each other on the same plane have a tapered and narrow protrusion at their tips, and a drum core around which a wire is wound on the protrusion is placed so that its center axis is relative to the metal plate terminal surface. It is arranged and fixed vertically so as to span between the protruding parts, and the terminal of the wire ring is connected to the metal plate terminal, and the whole is covered with exterior resin molding, leaving the connection part of the metal plate terminal to the external circuit. Ivy inductance parts.