JPS587692Y2 - filter - Google Patents

Description

[Detailed explanation of the invention] This invention is a filter that is connected to the line of the communal reception facility.
The details relate to the security structure of the filter.

In this type of safety structure, if a discharge protrusion is provided inside the housing close to the plug seat, and this protrusion is electrically connected to the housing, the transmission line can be connected to the plug. This method has a great effect in preventing the lightning surge that enters the housing from being discharged at the plug and having a negative effect on the circuit elements installed inside the housing. If a structure is to be formed, a new discharge protrusion must be created and provided within the housing, and this discharge protrusion must be well electrically connected (grounded) to the housing. In other words, it is necessary to form a reliable grounding circuit as shown by A in Fig. 4, and its installation requires the cost of special materials and additional effort. was there.

Therefore, the present invention aims to eliminate the above-mentioned drawbacks and provide a structure that not only has the safety of protecting the internal circuit, but also can be easily formed without increasing the number of components. That is.

The drawings showing the embodiments of the present application will be described below.

In FIGS. 1 to 3, 1 is a base material, 2 is a lid member attached to the base material, and a box is formed by these members.

As is well known, these base material 1 and lid body 2 are made of aluminum alloy or other well-known materials.

Reference numeral 3 denotes a mounting piece connected to the base material, and as is well known, a recess 4 or a through hole 5 is used to allow the box body to be mounted on an antenna mast or a wall of a building.

A chassis 6 is fixed to the base material 1 and is made of a material with good conductivity.

Reference numerals 7 and 8 denote plug seats that are fixed through the base material 1 and the chassis 6, and are used as input side terminals and output side terminals, respectively.

Further, these plug seats 7 and 8 are configured so that a plug connected to a transmission line (for example, a coaxial cable) constituting the line of the communal reception facility can be connected.

Next, 9, 9... are a plurality of filter elements provided inside the box, including a band pass filter, a bypass filter, and a low pass filter each having a different frequency band (for example, the band of different TV channels). etc. are provided.

In addition to the filter, various circuit elements such as an amplifier circuit requiring a shield case as described later may be provided.

In this filter element 9, 10 is a grounding plate that is mechanically and electrically integrated with the chassis 6, and 11 is a shielding case made of a material with good conductivity, such as an iron plate.
It is punched and formed into the unfolded state as shown in FIG.
It is formed by bending this.

Note that the punching and bending may be performed simultaneously using any press device.

Reference numeral 12 denotes a fixing gourd, and the shield case 11 is fixed by inserting the gourd into a through hole drilled in the ground plate 10 and soldering the claw 12 and the ground plate 10 in the inserted state. It is provided so as to be mechanically and electrically integrated with the ground plate 10.

Reference numeral 13 denotes an adjustment through hole drilled in the shield case 11, and is provided to adjust filter circuit elements such as capacitors and coils provided inside the shield case 11.

Note that this through hole is formed in a size that allows easy adjustment and a size that prevents external influences from being transmitted to the inside.

14 and 15 are insulated terminals fixed to the ground plate 10, respectively;
The input end and output end of the filter circuit element provided inside the shield case 11 are connected to each other.

Next, reference numeral 16 denotes a coil used as a connection circuit connecting the connector seat 7 and the input end of the filter circuit element, and as shown in FIG. They are connected to compensate for mutual impedance.

Note that as this connection circuit 16, a conductive wire may be simply used instead of a coil.

Reference numeral 17 denotes a coaxial cable connected between the insulated terminal 15 and the connector seat 8, which is used to guide the output signal of the filter element 9 to the connector seat 8 as an output terminal. The wire 17a is connected to the center conductor 8a and the insulated terminal 15 in the plug seat 8, and the outer conductor 17b
is the ground piece 18 connected to the chassis 6 and the ground plate 1 described above.
0.

Next, reference numerals 19 and 20 denote discharge projections formed by protruding a part of the shield case 11, and are arranged close to the insulating terminals 14 and 15, respectively.

Note that the distance between this protrusion 19 and the insulated terminal 14 or the protrusion 20
and the insulating terminal 15 are such that discharge occurs between them at a voltage lower than the withstand voltage of the filter circuit element disposed inside the shield case 11, respectively.

Further, the shapes of these protrusions 19 and 20 are preferably formed such that their tips are sharpened to facilitate discharge.

Furthermore, these protrusions may be located close to other parts of the connection circuit.

A filter circuit having the above-described configuration is shown in FIG.

That is, in the same figure, a shield case 11 is provided with filter circuit elements such as a large number of capacitors C and a large number of coils L, and their input terminals and output terminals are respectively connected to a plug seat 7 as an input side terminal. and is connected to the connector seat 8 as an output side terminal, and is further connected to the shield case 1.
The discharge protrusions 19 and 20 formed protruding from the connector 1 connect to the coaxial cable 17 as a connecting circuit 16 connecting the connector seat 7 and the filter circuit element and a connecting circuit connecting the connector seat 8 and the filter circuit element, respectively. are placed close together.

With the above configuration, the signal that enters the connector 7 from the line of the communal reception facility is passed through a filter circuit element disposed in the shield case 11, and further via the coaxial cable 17 to the connector 7. 8 is output.

In this state, if a lightning surge comes from the line connected to the connector seat 7, this surge voltage will be applied to the shield case 1.
If the withstand voltage is higher than the withstand voltage of the filter circuit element placed in the shield case 11, a discharge occurs between the protrusion 19 and the insulated terminal 14, the energy is annihilated, and the filter circuit element in the shield case 11 is affected. is not enough.

Note that even when a similar lightning surge enters the plug seat 8, a similar discharge occurs between the discharge projection 20 and the insulating terminal 15.

As mentioned above, in this invention, the shield case 11
The protrusion 19 is formed by protruding a part of the protrusion 19, and the protrusion 19 is placed close to the circuit 16 that connects the filter circuit element placed inside the shield case 11 and the plug seat 7. Even if a lightning surge enters from the receiving line towards the plug seat 7 of the filter, it can be discharged before it is transmitted to the filter circuit element placed inside the shield case, and this circuit element can be discharged. There is safety that can be protected.

Moreover, even if the protrusion 19 is provided to discharge lightning surges, the protrusion 19 is not included in the shield case 11 that is always used in this type of filter.
Since it is formed by protruding a part of the discharge member, even if such a discharge member is to be provided, it can be provided without increasing the number of members, which is economical and does not require extra cost. There are also the above effects.

Furthermore, as mentioned above, since the protrusion 19 is formed by protruding a part of the shield case 11, the above-mentioned shield case 11 is generally securely grounded. Protrusion 19 for discharge
At the same time, it has the advantage of ensuring the integrity of the grounding and making the reliability of the discharge extremely high as described above.
Another advantage is that such complete grounding can be obtained without any special grounding treatment, making its manufacture extremely simple.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is an exploded perspective view of the filter with a part of the lid broken away (the filter element and a part of the plug are shown in imaginary lines); The figure is a partial front view showing the relationship between the protrusion and the insulated terminal, Figure 3 is a developed view of the shield case, and Figure 4 is a circuit diagram. 1... Base material, 2... Lid body, 7, 8...
...Connection seat, 11...Shield case, 1
6...Connection circuit, 19.20...Protrusion.

Claims (1)

[Scope of utility model registration request] The box body is equipped with a plug seat, and the inside of the box body is provided with a shield case and a filter circuit element, and the filter circuit element is located inside the shield case, and the filter circuit element is located inside the shield case. In a filter in which the element is connected to the above-mentioned plug socket via a connection circuit, a part of the above-mentioned shielding case is made to protrude to form a discharge protrusion, and the protrusion is connected to a part of the above-mentioned connection circuit. A filter characterized in that the filters are arranged close to each other, and the interval between the filters is such that a discharge occurs between the two at a voltage lower than the withstand voltage of the filter circuit element.