JPH0414856Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electric circuit device in which an earth spring cut out from a cover is brought into contact with a shielding plate in a case in which an electric circuit is incorporated.

<Summary of the invention> The present invention is an electric circuit device in which an earth spring cut out from a cover comes into elastic contact with a shielding plate in a case in which an electric circuit is incorporated. By forming ribs with a groove-like cross section perpendicular to the curved part,
This eliminates the fatigue of the earth spring and makes the potential of each part of the shield plate the same as the earth potential.

<Conventional Example> FIG. 5 shows an exploded perspective view of an electronic tuner as a conventional example. 1 shows an electronic tuner consisting of a case 2 and a cover 3. The case 2 has a board 4 (the circuit components assembled on the board are not shown), and the board 4 is divided by a shielding plate 5 into compartments in which each circuit is assembled. ing. 7 is a compartment where the VHF band tuner part is assembled, 7a to 7d are
It shows the section where the UHF band tuner circuit is installed.
Section 7a is assembled with an input tuning circuit, section 7b is assembled with a primary-side double-tuned circuit, section 7c is assembled with a secondary-side double-tuned circuit and mixer circuit, and section 7d is assembled with a local oscillation circuit.

8a, 8b formed by cutting and raising the cover 3,
8c is an earth spring. These earth springs 8
When the case 2 is closed with the cover 3, the elements a, 8b, and 8c come into electrical and elastic contact with the upper part of the shielding plate 5. This state is shown in FIG.

FIG. 6 shows a sectional view taken along line A-A' in FIG. 5 with the case 2 closed with the cover 3. The reason why this earth spring is required is that the circuit is VHF.
Due to the high frequencies of the UHF and UHF bands, potential differences occur between the ground potentials of each part, and an earth spring is required to eliminate this potential difference.

<Problems to be solved by the invention> Earth springs 8a, 8b, 8 in the above conventional example
c has a problem in that stress is concentrated at its bending base, which causes elastic fatigue.
Also, this allows the earth springs 8a to 8c and the shielding plate 5 to
The electrical contact with any part of the
In addition, because the electrical contact resistance increases, the potential at the point of contact with the ground spring on the shield plate does not reach the ground potential, but becomes higher than the ground potential, resulting in leakage of the local oscillation frequency, reduction in the gain of the amplifier circuit, This causes various problems such as abnormal oscillation and the like.

The purpose of the present invention is to provide an electric circuit device that solves these various problems.

<Means for Solving the Problems> The electric circuit device according to the present invention has a configuration in which a rib is formed at the base of the earth spring.

<Function> With the above configuration, the stress concentrated at the base of the earth spring is dispersed, so that it is possible to reduce the fatigue of the earth spring and to reduce the electrical contact resistance between the shielding plate and the earth spring.

<Embodiment> FIGS. 1 to 4 are diagrams for explaining an embodiment of the present invention. In these figures, the same components as in FIGS. 5 and 6 are denoted by the same reference numerals, and explanations thereof will be omitted.

The difference between Fig. 1 and Fig. 5 is that the cover 1
Earth spring 18 cut and raised inward of 3
Ribs 9a, 9b, 9c having substantially V-shaped cross sections are formed at the bent bases (roots) of a, 18b, 18c.

FIG. 2 shows a sectional view taken along line B-B' in FIG. 1.
The tip of an earth spring 18a, which has a rib 9a formed at its base, is in elastic pressure contact with the upper surface of the shielding plate 5a.

FIG. 3 shows a partially enlarged perspective view of the cover 13 in which only the earth spring 9a is enlarged in order to explain the shape of the ribs. The rib 19a is perpendicular to the bent portion 10 of the earth spring 18a, and has a V-shaped cross section. Note that the cross-sectional shape of this rib is not particularly limited to a V-shape, and may be formed in other shapes such as a U-shape, for example.

Figure 4 shows a characteristic diagram of the amount of deflection when a load is applied to the earth spring. The curves in the figure represent the characteristic curves of the earth spring to which the embodiment of the present invention is applied, and the curves represent the characteristic curves of the conventional earth spring. As is clear from this figure, the amount of deflection for any given load is smaller for the curve. This means that the settling of the earth spring is small and the elastic pressing force of the earth spring against the shielding plate is high.

Although the above embodiment has been described as an example applied to an electronic tuner, the present invention is not limited to this, and it goes without saying that the present invention can be applied to other circuit devices.

<Effects of the invention> According to the electric circuit device of the invention described above,
It can reduce the fatigue of the earth spring. Furthermore, the elastic pressing force of the earth spring can be strengthened. These things increase the elastic contact force between the earth spring and the shielding plate, and reduce the electrical contact resistance between them. This ensures that the potential of the shielding plate where the earth spring is in contact is maintained at the ground potential, which prevents leakage of local oscillation signals and solves various problems such as reduction in amplifier gain and abnormal oscillation. I can do that.

[Brief explanation of drawings]

1 to 3 show diagrams for explaining one embodiment of the present invention. FIG. 1 is an exploded perspective view of the electronic tuner, FIG. 2 is a sectional view of the electronic tuner, FIG. 3 is an enlarged perspective view of the earth spring, and FIG. 4 is a characteristic diagram of the load versus deflection of the earth spring. FIG. 5 is an exploded perspective view of a conventional electronic tuner, and FIG. 6 is a sectional view of the tuner shown in FIG. 1...Electronic tuner, 2...Case, 3,13
... Cover, 4 ... Board, 5 ... Shielding plate, 9a,
9b, 9c...Rib, 18a, 18b, 18c...
...Earth spring.

Claims (1)

[Scope of utility model registration request] It consists of a case, a shielding plate that partitions and shields the inside of the case, a cover that covers the case, and an earth spring cut and raised from the cover so as to come into elastic contact with the shielding plate. An electric circuit device characterized in that a rib having a groove-like cross section is formed perpendicular to a bent portion of an earth spring.