JPH04112509A - Choke coil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a choke coil for high frequencies used, for example, in the VHF band.

BACKGROUND OF THE INVENTION In recent years, it has become increasingly important to use choke coils over a wide range of VHF bands.

Conventionally, this type of choke coil is shown in Figs. 4(a) and (b).
) The configuration was as shown in . In FIG. 4, 5 is a conductor wire, and both ends (hatched portions) 7 and 8 are soldered 7° 8. 6 is a ferrite core. That is, in order to increase the inductance value, the air-core coil formed by the conductor wire 5 and the ferrite core 6 are magnetically coupled. Further, in order to prevent the conductor wire 5 from shifting due to the inclination of the ferrite core 6, both are fixed with an adhesive.

Problems to be Solved by the Invention In such a conventional configuration, it is necessary to form an air-core coil portion with the conductor wire 5, insert the ferrite core 6, and then fix the two with adhesive. However, there is a problem in that it takes time and effort to manufacture the choke coil.

The present invention solves these problems and aims to reduce the labor involved in manufacturing choke coils.

Means for Solving the Problems In order to achieve this object, the present invention provides a rod-shaped core whose outer diameter at both ends is thinner than the outer diameter of the central portion, and a central portion whose outer diameter is thicker than one end of the core, which has a narrower outer diameter. The conductor is tightly wound through the outer diameter of the conductor to the other end having a narrow outer diameter.

According to the above-described structure, the present invention secures magnetic coupling between the air-core coil portion and the core by closely winding the conductor wire around the core having a small outer diameter at both ends, and without using an adhesive. This prevents the core from shifting.

EXAMPLE Hereinafter, an example of the choke coil of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a conductor wire. 2 is a rod-shaped ferrite core whose outer diameter at both ends is thinner than that at the center. Both end portions of the conductor wire 1 are subjected to soldering treatment (indicated by hatching 3 and 4, hereinafter referred to as soldering treatment portions). The air core coil connects the conductor wire 1 to the ferrite core 2.
The inductance value is increased by the ferrite core, which is formed by winding the ferrite core around the outer periphery of the ferrite core and is magnetically coupled to the ferrite core. In addition, the ferrite core 2 has a wire wound several times around the narrow outer diameter part at one end of the ferrite core 2, a few more windings around the center, and several windings around the remaining narrow outer diameter part. This prevents the air-core coil and ferrite core 2 from coming apart.

FIG. 2 shows an example in which the choke coil of the present invention is used for surface mounting. In this embodiment, the soldering processing section 3
．． 4 is wound around the ferrite core 2 at least once, so that it can be surface mounted and soldered onto the base i.

In FIG. 3, the ferrite core 2A has a rectangular cross section, which prevents rotation during surface mounting and improves mounting position accuracy.

Effects of the Invention As described above, according to the present invention, since the conductor wire is wound around a core whose outer diameter at both ends is smaller than that at the center, there is no need to fix the core and the conductor wire with adhesive. This results in good manufacturability.

[Brief explanation of the drawing]

Figures 1 (a) and (bl are front and side views of a choke coil according to one embodiment of the present invention, and Figures 2 (a) and (b) are front views of a choke coil according to another embodiment of the present invention. 1 side view, FIGS. 3(a), (b) are a front view, side view, FIG. 4(a), and FIG.
(b) is a front view and a side view of a conventional choke coil. 1... Conductor wire, 2... Ferrite core, 34... Soldering processing section. Name of agent: Patent attorney Akira Okaji et al. 22 No. 1
Figure [Qn (b) Figure 2 (α) (b Figure (phantom) / Figure (It) B)

Claims (2)

[Claims] (1) A rod-shaped core whose outer diameter at both ends is smaller than the outer diameter at the center, and the core is tightly wound from one end with the smaller outer diameter to the other end with the smaller outer diameter via the center part with the thicker outer diameter. Choke coil with conductor wire. (2) The choke coil according to claim 1, wherein both ends of the conductor wire are soldered and the soldered portion is wound around a ferrite core at least once.