JPS6290911A - Balun coil - Google Patents

Abstract

PURPOSE:To manufacture a balun coil inexpensively in mass production by winding two or more coils in two or more winding grooves, disposing a rodlike ferrite core in contact with a flange, and wiring a terminal formed at the flange to simplify the winding work, thereby stabilizing the performance. CONSTITUTION:Coils 3, 4 are wound in a winding groove 8 and coils 1, 2 are wound in a winding groove 9 of a drum-shaped ferrite core 5 having the grooves 8, 9. Terminals are provided at flanges 10a, 10b, 10c of the core 5, and wired. In order that a balun coil is not affected externally by electromagnetic influence or does not externally affect, a rod-shaped ferrite core 6 is provided to contact the flanges 10a, 10b, 10c of the core 5. Thus, the irregularity of the coupling degree of coils and the irregularity of the characteristic impedance of a transformer of a transmission line are reduced to connect other circuit portions with the terminals. The irregularity of the wiring lead length is reduced, and the magnetic influence can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a balun coil used in antennas and the like.

Conventional technology A conventional balun coil is a ring-shaped ferrite core as shown in Figure 5, as shown in "Toroidal Utilization Encyclopedia" published by CQ Publishing Co., Ltd., page 354 (Figures 6-20: How to make a balun). It is well known that a balun coil is formed by using two transmission line type transformers each having coils 15 and 16 wound around wire 14 and connecting them as shown in FIG. FIG. 6 shows an equivalent circuit diagram of FIG.

That is, the conventional balun coil has a structure in which two coils 16 and 16 are wound around a ring-shaped ferrite core 14, and the wires are connected as shown in FIG. 7.

Problems to be Solved by the Invention However, in such a structure, the ring-shaped ferrite core 1
Since the shape is closed as shown in 4, the winding work of winding the coils 15 and 16 is troublesome, the production cost is high, and the ends of the coils 15 and 16 are directly connected to other circuit parts. Therefore, it becomes close to aerial wiring and the characteristics become unstable. Further, there was a problem in that the work of connecting and fixing the balun coil was troublesome and difficult to use.

The present invention is intended to solve these problems, and aims to provide a balun coil that simplifies winding work, stabilizes performance, and enables mass production at low cost. be.

Means for Solving the Problem In order to solve this problem, the present invention replaces the ring-shaped ferrite core with a drum-shaped ferrite core having two or more winding grooves and a rod-shaped ferrite core. Two or more windings a are formed in two or more winding grooves of the ferrite core to form two or more transmission line transformers, terminals are provided in three or more flanges of the drum-shaped ferrite core, and these three A rod-shaped ferrite core is arranged so as to be in contact with three or more flange portions, and wires are connected to the terminals.

According to this structure, two or more windings are respectively formed in two or more winding grooves of a drum-shaped ferrite core having winding grooves,
By configuring a transmission line transformer of more than one set, and wiring the transmission line transformer to the part protruding from the upper part of the terminal provided on three or more flanges of the drum-shaped ferrite core so as to function as a balun coil. Furthermore, the wire lengths of each coil can be made equal, and variations in coupling between coils and variations in characteristic impedance can be made very small. In addition, each flange tJa is made of a rod-shaped ferrite core.
This creates a closed magnetic circuit loop that is well protected against electromagnetic interference.

EXAMPLE An example of the present invention will be explained below using drawings. Figure 1 is a structural diagram of a balun coil according to an example of the present invention. In Figure 1, a drum having a winding groove 8.9 is shown. The coils 3 and 4 are provided in the winding groove 8 of the drum-type ferrite core 5, and the coils 1 and 2 are provided in the winding groove 9 by winding.
7 terminals on each of the flange parts 10a, 10b, 100,
7B.

70.7D and 7F are provided, and wiring is performed to the terminals 7A to 7F. In order to prevent the balun coil from being electromagnetically influenced by the outside, the rod-shaped ferrite core 6 is attached to the flange portion 10a of the drum-shaped ferrite core 5.
, 10b, and 10c.

Fig. 2 shows a combination of a rod-shaped ferrite core 6 and a drum-shaped ferrite core 5 having a semicircular recess 11. By providing a semicircular recess 11 in the rod-shaped ferrite core 6,
If a drum-shaped ferrite core 5 having a semicircular concave portion 11 is used, this is possible without shifting.

FIG. 3 shows a top view of the balun coil showing the wiring of the coil.

A coil 1.2 is provided with a wire in the winding groove 9, a coil 3.4 is provided with a wire in the winding groove 8, and terminals 7A, 7B, 70, 7D, 7F are connected as shown in the equivalent circuit diagram of FIG. Wire the coil on the top of the drum-shaped ferrite core 5, and connect the balun coil to other circuit parts using the 7 terminals (7B, 7G, TI).
Since the installation of the balun coil is carried out at the lower part of the 7th floor, the terminal and the coil wiring part will not be cut off even if mechanical stress is sometimes applied to the terminal, and the balun coil will not be disconnected from the flange part 10a of the drum-shaped ferrite core 6. , 10b, 10
C has terminals 7M, 7B, and 7G.

The reason why 7D and 7F are provided is to prevent the coils 1 to 4 wound in the winding grooves 8 and 9 from being magnetically coupled to each other.

Effects of the Invention As described above, in the balun coil of the present invention, the coil is wound around a drum-shaped ferrite core, and the coils are connected by wiring to the terminal provided on the flange of the drum-shaped ferrite core. It also reduces the variation in the characteristic impedance of the transmission line transformer, eliminates the need to connect to other circuit parts with terminals, reduces the variation in the wiring lead length, and reduces the magnetic It is not easily affected and its structure allows for mass production, making it possible to reduce costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a balun coil of one embodiment Wl of the present invention,
FIG. 2 is a perspective view of another implementation row showing a method of holding the rod-shaped ferrite core of the balun coil of FIG. 1, and FIG. 3 is a top view of the balun coil of FIG. 1 with the rod-shaped ferrite core removed. Figure 4 is an equivalent circuit diagram of the balun coil in Figure 3, and Figure 5 is an equivalent circuit diagram of the balun coil in Figure 3.
The figure is a perspective view of a conventional balun coil, FIG. 6 is an equivalent circuit diagram, and FIG. 7 is a wiring diagram thereof. 1. 2, 3.4... Coil, 5... Drum-shaped ferrite core, 6... Rod-shaped ferrite core, 7A. 7B, 7G, 7D, 7F...Terminal, 8,
9... Winding groove of drum-shaped ferrite core, 10&
, 10b. 10C... Flange of drum-shaped ferrite core, 11... Semicircular recess. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure t12 Figure 3 Figure 4? Figure 5 Figure 6 If Figure 7 Z

Claims (3)

[Claims] (1) A drum-shaped ferrite core having two or more winding grooves, with two or more windings each in the two or more winding grooves,
A balun coil with a rod-shaped ferrite core placed in contact with the flange of a drum-shaped core, and wired to a terminal provided on the flange. (2) The balun coil according to claim 1, wherein the flange portion of the drum-shaped ferrite core is provided with a recess into which the rod-shaped ferrite core is inserted. (3) The balun coil according to claim 1, wherein a terminal insertion groove is provided in the flange portion of the drum-shaped ferrite core.