JPS6236356Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tuner with a capacitor unit in which a capacitor unit having a ground capacitor and a coupling capacitor serving as a bypass capacitor is attached to an outer box.

In TV receivers, in order to prevent image disturbances such as ghosts and reflected images caused by reflection of signal radio waves, and at the same time improve transmission efficiency and prevent back-and-forth reflections of signals on feeder lines, the conventional method is shown in Figure 1. As shown, a coupling capacitor C ₁ is connected to the center conductor 2 of the coaxial cable 1, and a bypass capacitor is connected to the outer conductor 3 to pass unnecessary frequency signals.
Antenna input circuit unit 4 connected to _C2 has been used. Conventionally, the antenna input circuit unit 4 was connected by inserting it in the middle of the coaxial cable 1, but this method was cumbersome to handle and did not provide a sufficient effect of improving the characteristics. Recently, as shown in FIG. 2, a tuner with a capacitor unit has been proposed in which a capacitor unit 4 serving as an antenna input circuit unit is directly attached to an outer box 5 which also serves as a shield case of the tuner.

However, the conventional capacitor unit 4
A connector 7 into which an F-type plug or phono jack, etc. is inserted is attached to a support 6 made of an insulating material such as plastic, and a connector 7 is inserted between the outer cylindrical conductor 7a of the connector 7 and the outer case 5 of the tuner. , one or two bypass capacitors _C2 having lead wires are connected, and a coupling capacitor _C1 having lead wires is connected between the center conductor 7b passing through the center of the outer cylindrical conductor 7a and the input end of the tuner. Because it was designed to be connected, it had the following drawbacks.

(b) Since capacitors C ₁ and C ₂ have lead wires, the inductance of the lead wires acts,
The frequency characteristics of the VHF and UHF bands deteriorate, the reflection coefficient increases, and the lead inductance is large, making it difficult to match the characteristic impedance of the coaxial cable.

(b) Since the capacitors C ₁ and C ₂ are surrounded by the support 6 made of insulating resin or the like, the shielding effect is not sufficient and external noise easily enters.

(c) The withstand voltage of capacitor _C2 is low, making it vulnerable to lightning strikes, etc., and lacking in safety.

(d) The capacitor _C2 must be soldered between the outer cylindrical conductor 7a and the outer case 5, making assembly cumbersome.

The present invention eliminates this drawback and provides a tuner with a capacitor unit that has good frequency characteristics, can effectively prevent the entry of unnecessary radiation waves, has a high withstand voltage, and is easy to assemble. purpose.

In order to achieve this purpose, the present invention provides a tuner with a capacitor unit attached to the outer box.
The capacitor unit is inserted between a feedthrough type capacitor having a feedthrough conductor connected to one electrode and the other electrode fixed on a grounding fitting, a center conductor passing through an inner diameter of the feedthrough conductor, and a tuner input end. The through conductor is formed into a stepped tube shape having a small tube portion and a large tube portion, the small tube portion is passed through the through hole of the feedthrough capacitor, and the small tube portion and the large cylindrical part are connected and fixed to one of the electrodes of the feedthrough capacitor, and an insulating cylindrical body with the center conductor embedded in the axial center part is inserted therein, the through conductor, A box in which the insulating cylindrical body and the center conductor constitute a connector for an external connector, one surface of the grounding metal fitting is attached and fixed on one surface of the outer box, and the other surface opposite to the one surface has a through hole. The through-hole capacitor is fixed to a peripheral portion of the upper surface of the through hole of the grounding metal fitting, and the coupling capacitor is housed inside the grounding metal fitting.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be specifically described below with reference to the accompanying drawings, which are examples. FIG. 3 is a partial sectional view of the main parts of the tuner with capacitor unit according to the present invention. In the figure, 8 is an outer box of the tuner, which is made of a metal material such as aluminum to form a shield case. Reference numeral 9 denotes a capacitor unit mounted on one side plate of the outer box 8 with screws 10, 11, etc.

The capacitor unit 9 has a structure in which a feedthrough capacitor 14 serving as a bypass capacitor and a coupling capacitor 15 are incorporated into a grounding fitting 13.

The grounding metal fitting 13 serves both as a support case and a shield case, and is formed into a box shape from a metal material such as aluminum.

In addition, the feed-through capacitor 14 has a circular ceramic capacitor 18 having electrodes 16 and 17 around a through hole that is open on both sides, inside a stepped cylindrical external terminal fitting 19 that constitutes a part of the grounding fitting 13. The electrodes 17 are fixed to each other by means of soldering or the like so that they are in contact with each other, and the magnetic capacitor 1 is attached to the electrodes 16.
A cylindrical through conductor 20 passed through the through hole of No. 8.
are fixed by means such as soldering, and insulating resins 21, 2 are placed around the ceramic capacitor 18 surrounded by the through conductor 20 and the external terminal fitting 19.
It has a structure filled with 2. The feedthrough capacitor 14 is assembled by fitting the external terminal fittings 19 into the through holes 24 provided in the one side plate 23a of the shield case part 23 constituting the grounding fitting 13, and by soldering the surroundings. is fixed on the outer surface of the

An insulating cylindrical body 26 with a center conductor 25 embedded in its axial center is inserted into the inside of the through conductor 20, and the through conductor 20, the cylindrical body 26, and the center conductor 25 form a
A connector for external connectors is configured.

The through conductor 20 is formed into a stepped cylindrical shape having a small cylindrical part and a large cylindrical part. is connected and fixed to the electrode 16 of the feedthrough capacitor 14 by soldering. With such a structure, the feedthrough capacitor 1 is
4, the protruding length of the through conductor 20 is accurately determined, and the connection with the external connector is ensured. The through conductor 20 can be reliably soldered and fixed to the electrode 16 of the shaped capacitor 14 to increase the mechanical connection strength, and prevent the through conductor 20 from peeling off or becoming unstable due to insertion and removal of external connectors.

The coupling capacitor 15 is housed inside a shield case part 23 that constitutes the grounding fitting 13, and
Two lead wires 15a and 15b are soldered and fixed to the center conductor 25 and the tuner input end, respectively. This coupling capacitor 15 may be an ordinary capacitor, but in order to prevent fires and electric shocks caused by lightning strikes, etc., a capacitor is used as shown in Fig. 4.
It is preferable to construct the RC composite part with a discharge gap in which a resistor R ₁ and a discharge cap g ₁ are provided in parallel with C ₁ .

FIG. 5 shows an equivalent circuit diagram of the capacitor unit in the above embodiment, in which bypass capacitors C ₂₁ and C 22 formed by the feed-through capacitor 14 are connected between the feed-through conductor 20 and the grounding fitting 13, and the center conductor ₂₅ and tuner input The circuit configuration is such that a coupling capacitor 15 is inserted and connected in series between the two.

In this case, the present invention has a structure in which the feedthrough capacitor 14 constituting the bypass capacitor is fixed on the grounding fitting 13 and grounded.
Since lead wires are not required, there is no lead inductance of the lead wires, and therefore frequency characteristics can be improved and unnecessary radiation waves can be effectively prevented from entering. Moreover, since the bypass capacitor is composed of a feed-through capacitor 14 that is easy to insulate, such as by filling with insulating resins 21 and 22, and has a high withstand voltage, the withstand voltage is much higher than that of conventional ones, and reliability is improved. improves.

Also, when assembling, the feedthrough capacitor 14
It is only necessary to fix the lead wire on the grounding fitting 13 by means such as soldering, which eliminates the need for troublesome and unstable soldering of lead wires, which simplifies the assembly work and at the same time prevents electrical and mechanical problems after assembly. connection becomes more reliable. Further, as shown in the embodiment, if the feedthrough capacitor 14 is fixed to the outer surface of the one surface plate of the grounding fitting 13, the space is small and the assembly is easy. .

Furthermore, a center conductor 25 passing through the inner diameter part of the cylindrical through conductor 20 constituting the feedthrough capacitor 14 has a
Since the configuration is to connect the coupling capacitor 15,
A bypass capacitor _C23 is formed by the feedthrough capacitor 14 around the center conductor 25, and the effect of improving frequency characteristics and preventing the entry of unnecessary radiation waves is further enhanced. Moreover, as shown in the embodiment, the coupling capacitor 15 is connected to the grounding metal fitting 1.
It is housed inside the shield case part 23 that constitutes the third part, and almost perfect shielding effect can be obtained.

FIG. 6 is a partial sectional view of the main parts of another embodiment of the tuner with capacitor unit according to the present invention. In the figure, the same reference numerals as in FIG. 3 indicate functionally identical components. The feature of this embodiment is that a recessed receiving part 27 is provided on one side plate 23a of the shield case part 23 constituting the grounding fitting 13, and the recessed receiving part 27 is recessed from the outside toward the inside.
By fixing the ceramic capacitor 18 inside,
This is because the feedthrough capacitor 14 is configured. With such a structure, the external terminal fitting 19 is not required, so the number of parts is reduced from the embodiment shown in FIG.
The advantages of reduced assembly man-hours, lower costs, and smaller size can be obtained.

FIG. 7 shows a partial sectional view of the main parts of still another embodiment of the tuner with capacitor unit according to the present invention. The feature of this embodiment is that the one side plate 2 of the shield case part 23 that constitutes the grounding fitting 13 is
3a is provided with a raised part 28 extending from the inside to the outside, and the ceramic capacitor 1 is placed on the outer surface of the raised part 28.
8 is fixed to form the feedthrough capacitor 14. With this structure, the creepage distance between the electrode 16 of the ceramic capacitor 18 and the shield case portion 23 serving as the grounding fitting 13 is the same as that between the outer edge of the electrode 16 and the shield case portion 23, which is the grounding fitting 13, as shown in an enlarged view in FIG. Since the cap g ₁ between the cap and the outer periphery of the magnetic capacitor 15 increases to the value obtained by adding the gap g ₂ due to the thickness of the ceramic capacitor 15, the withstand voltage is greater than the embodiment shown in FIG. 3 or 6 in which only the gap g ₁ is present. becomes higher and reliability improves.

Another feature of the embodiment shown in FIG. 7 is that an appropriate number of holes 29 are provided in the side surface 28a of the floating portion 28. By providing such a hole 29, when filling the insulating resins 21 and 22, the insulating resin can be simultaneously injected and filled from the inside to the outside of the shield case part 23, using the hole 29 as a flow path for the insulating resin. Injecting and filling the resins 21 and 22 becomes very easy. Moreover, since the insulating resins 21 and 22 are integrated with each other by the holes 29, the distribution of residual stress that should be generated during curing shrinkage or heat cycle testing is made uniform, and the insulation voltage and temperature characteristics are improved. improves. In addition, in Fig. 7, 30
is an insulating case that seals the insulating resin 22.

As described above, according to the present invention, the following effects can be obtained.

(a) In a tuner with a capacitor unit attached to the outer box, the capacitor unit consists of a feed-through type capacitor in which a through conductor is connected to one of the electrodes and the other electrode is fixed on a grounding fitting, and Since it has a coupling capacitor inserted between the center conductor passing through and the tuner input end, the feed-through capacitor, which becomes a bypass capacitor, does not have a lead wire, has good frequency characteristics, and is effective in preventing the intrusion of unnecessary radiation waves. It is possible to provide a tuner with a capacitor unit that can prevent this from occurring.

(b) An insulating cylindrical body with the center conductor embedded in its axial center is inserted into the through-hole conductor, and the through-hole conductor, the insulating cylindrical body, and the center conductor constitute a connector for an external connector; When connecting a coaxial cable or the like, an external connector is attached to the end of the cable so that it can be easily inserted and removed, and a tuner with a capacitor unit that is easy to handle can be provided.

(c) The feedthrough conductor is formed into a stepped tube shape having a small tube portion and a large tube portion, and the small tube portion is passed through the through hole of the feedthrough capacitor, and the step between the small tube portion and the large tube portion is formed. Since the part is connected and fixed to one of the electrodes of the feed-through capacitor, the step part allows accurate positioning of the feed-through conductor with respect to the feed-through capacitor, and ensures the connection with the external connector. We have developed a tuner with a capacitor unit that securely solders the feedthrough conductor to the electrode of the feedthrough capacitor to increase the mechanical connection strength and prevent the feedthrough conductor from peeling off or wobbling due to the insertion and removal of external connectors. Can be provided.

(d) One side of the grounding fitting is attached and fixed on one side of the tuner outer box, and the other side opposite to the one side is formed into a box shape with a through hole, and the area around the upper side of the through hole of the grounding fitting is Since the feedthrough capacitor is fixed to the feedthrough capacitor, it is easy to attach the feedthrough capacitor and feedthrough conductor assembly to the grounding metal fitting, and to attach the grounding metal fitting to the outer box, as well as to easily insert and remove external connectors from the feedthrough conductor. It is possible to provide a tuner with a capacitor unit.

(e) Since the grounding fitting is formed into a box shape to accommodate the feedthrough capacitor and the coupling capacitor, it is possible to provide a tuner with a capacitor unit that has a high shielding effect.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional antenna input circuit.
FIG. 2 is a partial sectional view of a part of a conventional tuner with a capacitor unit, FIG. 3 is a partial sectional view of a main part of a tuner with a capacitor unit according to the present invention, and FIG. 4 is an equivalent circuit diagram of a coupling capacitor. FIG. 5 is an equivalent circuit diagram thereof, FIG. 6 is a partial sectional view of a main part in another embodiment, and FIG.
The figure is a partial sectional view of a main part in another embodiment, and FIG. 8 is an enlarged sectional view of a part thereof. 8... Outer box, 9... Capacitor unit, 13
...Grounding fitting, 14...Feedthrough capacitor, 15
... Coupling capacitor, 16, 17 ... Capacitor electrode, 18 ... Ceramic capacitor, 19 ... External terminal fitting, 20 ... Cylindrical through conductor, 25 ... Center conductor.

Claims (1)

[Scope of utility model registration request] In a tuner with a capacitor unit attached to the outer box, the capacitor unit includes a feed-through type capacitor in which a through conductor is connected to one of the electrodes and the other electrode is fixed on a grounding fitting, and a center conductor that passes through the inner diameter of the through conductor. It comprises a coupling capacitor inserted between the conductor and the tuner input end,
The through conductor is formed into a stepped cylindrical shape having a small cylindrical part and a large cylindrical part, the small cylindrical part is passed through the through hole of the feedthrough capacitor, and the stepped part between the small cylindrical part and the large cylindrical part is formed. is connected and fixed to one of the electrodes of the feedthrough capacitor, and an insulating cylinder with the center conductor embedded in its axial center is inserted therein, and the through-hole conductor, the insulator, and the center conductor A connector for an external connector is constructed, and the grounding metal fitting is formed into a box shape with one side fixed and fixed on one side of the outer box and having a through hole on the other side opposite to the one side. A tuner with a capacitor unit, characterized in that the feedthrough capacitor is fixed to a peripheral portion on the upper surface side of the through hole, and the coupling capacitor is housed inside the grounding fitting.