JPH04109518U - Filter device for preventing interference waves - Google Patents

Abstract

(57) [Summary] [Purpose] In a filter device for preventing interference waves using a choke coil, excellent attenuation characteristics of interference waves can be obtained over a wide frequency band from low frequency region to high frequency region.
In addition, a small, lightweight, and inexpensive product can be obtained. [Structure] Two ferrite cores 5 and 6 are wound with coil wires 7 and 8, respectively, and a choke coil is provided with a plurality of mutually insulated magnetic circuits 10 and 11.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is related to the improvement of a filter device for preventing interference waves using a choke coil. It is something that

0002

[Conventional technology]

Figure 7 shows the common mode used in this type of conventional interference wave prevention filter device. 8 is a circuit diagram of a choke coil, and FIGS. 8 and 9 are perspective views showing its appearance. be. In these figures, 1 is a ferrite core, 2 and 3 are coil wires, and 4 is a ferrite core. It is a spool made of insulating material.

0003 The common mode choke coil with the above configuration uses polyethylene as the spool 4, which is an insulator. Winding is performed using two coil wires 2 and 3 such as stell covered wires, and this winding is performed. The ferrite core 1 is formed by inserting the ferrite core 1 into the spool 4. Figure 8 shows U An example of using ferrite core 1 with U and UI type core shapes, and Figure 9 shows EI and EE type ferrite cores. Examples in which a core-shaped ferrite core 1 is used are shown. Also, Figure 10 9 is an exploded perspective view of the choke coil of FIG. 9. FIG.

0004 Here, in order to increase the amount of attenuation of interference waves in the low frequency region, it is necessary to use a large filter. Either use ferrite core 1 or use this option as shown in Figures 11 and 12. It is necessary to use multiple coils connected in series. Figure 11 shows choke carp. FIG. 12 is a circuit diagram when two cables are connected in series, and FIG. 12 is a perspective view showing its appearance.

[0005]

[Problem that the idea aims to solve]

The above is a filter device for preventing interference waves using a conventional common mode choke coil. The choke coil has a large number of windings and a large shape. Therefore, the stray capacitance in the winding section increases, deteriorating the high frequency characteristics, and thus reducing the magnetic Since the air circuit cannot be enlarged, the amount of attenuation of interference waves in the low frequency region is low, and EI, When two non-insulated magnetic circuits are formed using an EE-shaped core, additional windings are required. The stray capacitance of the line increases, and the amount of attenuation of interference waves in the high frequency range becomes significant. There was a problem in that it decreased rapidly.

[0006] Also, when using multiple choke coils connected in series, Each choke coil is mechanically separated, which makes it difficult to use and has poor production efficiency. Low frequency There is a problem in that the amount of attenuation of interference waves in the area is low.

[0007] This idea was created by focusing on the problems mentioned above, and was developed in the low frequency region and A small, lightweight, and inexpensive interference wave prevention device that achieves high attenuation of interference waves in the high frequency range. The purpose of this invention is to obtain a filter device for stopping.

[0008]

[Means to solve the problem]

The interference wave prevention filter device of this invention uses a choke coil. The choke coil has multiple magnetic circuits insulated from each other. .

[0009]

[Effect]

In the interference wave prevention filter device of this invention, magnetic circuits are isolated from each other. The effective magnetic circuit is large and the attenuation is high even in the low frequency range. can get. In addition, the number of windings of the choke coil is small, and the winding part is floating. Free capacitance is reduced, high attenuation can be obtained in the high frequency range, and the device is small and lightweight.

0010

【Example】

Figure 1 shows the components used in a filter device for preventing interference waves according to one embodiment of this invention. FIG. 3 is a circuit diagram of a mode choke coil. Figure 2 is a perspective view showing its appearance. be. This choke coil has two ferrite cores 5 and 6 divided into two. The coil wires 7 and 8, such as polyester coated wires, are made of an insulating material. It is wound via a spool 9. The magnetic circuit 1 of the choke coil The structure is such that a plurality of 0 and 11 (in this case two) are insulated from each other. Ru.

[0011] FIG. 3 is a sectional view taken along the line AA in FIG. 2. As shown, two ferrite cores The coil wires 7 and 8 are insulated from each other by a spool 9. Also , FIG. 4 is an exploded perspective view of the choke coil in FIG. 2, and FIG. 5 is an external view of the spool 9. This shows the situation. As before, first attach the coil wires 7 and 8 to this spool 9. Winding is performed by the spool 9, and the ferrite cores 5 and 6 are inserted into the spool 9. child As a result, the common mode choke coil shown in FIG. 2 is completed.

0012 In a filter device having a common mode choke coil formed as described above, Then, interference wave components passing through the coil wires 7 and 8 are removed. At that time, they are mutually exclusive. Since it has a plurality of magnetic circuits 10 and 11 that are bordered, the effective magnetic circuit is large. , a high amount of attenuation of interference waves can be obtained not only in the high frequency region but also in the low frequency region. Also, chi The same performance is ensured even if the number of turns of the choke coil is less (1/2 in the example) The stray capacitance of the winding part is reduced, and the characteristics in the high frequency range are also improved. becomes. At the same time, it is small, lightweight, and inexpensive.

[0013] Figure 6 shows the relationship between the frequency (MHz) of the interference wave and the amount of attenuation (-dB). Ru. In the figure, the solid line (thin line) in (a) is the conventional choke coil shown in Fig. 8; The chain line in (C) is the conventional choke coil shown in Fig. 9, and the dotted line in (C) is the conventional choke coil shown in Fig. 12. The solid line (thick line) in (d) is the choke coil of the present example shown in Fig. 2. The cases in which coils are used are shown, and both use ferrite cores made of the same material. This is comparative data when the coil wire is wound with the same number of turns. illustration As shown in the figure, the choke coil of this example has a has significantly increased compared to conventional products, and the attenuation characteristics are also better than conventional products in the high frequency range. has improved. Therefore, it is possible to use a wide frequency band as a filter device for preventing interference waves. A high rejection rate of disturbance waves can be obtained over a long period of time, and it is a highly economical and excellent rejection rate. It becomes effective.

[0014]

[Effect of the idea]

As described above, according to this invention, multiple magnetic circuits of choke coils are connected to each other. Because it is insulated, the amount of attenuation of interference waves is high in the low frequency region and high frequency region. The attenuation characteristics of interference waves are improved over a wide frequency band, and the design is compact and lightweight. This has the effect of reducing the quantity and cost.

[Brief explanation of drawings]

[Figure 1] Circuit diagram showing one embodiment of this invention

[Figure 2] A perspective view showing the appearance of the choke coil in Figure 1.

[Figure 3] Cross-sectional view taken along the A-A plane in Figure 2

[Figure 4] Exploded perspective view of the choke coil in Figure 2

[Figure 5] A perspective view showing the external shape of the spool in Figure 2

[Figure 6] Characteristic diagram showing the relationship between interference wave frequency and attenuation amount

[Figure 7] Circuit diagram showing a conventional example

[Figure 8] A perspective view showing an example of the choke coil in Figure 7.

[Figure 9] A perspective view showing another example of the choke coil in Figure 7.

[Figure 10] Exploded perspective view of the choke coil in Figure 9

[Figure 11] A circuit diagram showing an example in which the choke coils in Figure 7 are connected in series.

[Figure 12] A perspective view showing the appearance of the choke coil in Figure 11.

[Explanation of symbols]

5,6 Ferrite core 7,8 Coil wire 9 Spool 10,11 Magnetic circuit

Claims (1)

[Scope of utility model registration request] 1. A filter device for preventing interference waves using a choke coil, characterized in that a plurality of magnetic circuits of the choke coils are provided insulated from each other.