JPH023669Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to the structure of a shield case for high-frequency equipment such as television channels and CATV converters. By stacking an inner cover and an outer cover on top of each other, and pressing the inner cover above the small chamber with a bulge formed in the outer cover that protrudes toward the small chamber, the inner cover is pressed against the edge. The purpose is to provide a shield case structure for high frequency equipment with high shielding effect.

Conventionally, as a shield case structure for this type of high frequency equipment, there has been a structure as shown in FIGS. 1 and 2, for example. Figure 1 is an exploded perspective view (high-frequency circuit parts assembled inside are omitted), Figure 2 is an exploded perspective view of the
The figures each show a longitudinal sectional view. Reference numeral 1 denotes a metal shield case whose interior is divided into small chambers by a partition plate 2, and an appropriate number of substantially T-shaped protrusions 4 are formed on the partition plate 2 and the shield case side plate 3 on the open surface side. It has been done. Reference numeral 5 denotes an inner cover made of an elastic thin metal plate placed on the open surface of the shield case 1, and has slots 6 corresponding to the number of the projections 4.
is drilled. Reference numeral 7 denotes a metal outer cover that is attached to the shield case 1 from above the inner cover 5, and is provided with a slot 6 like the inner cover 5, and is provided in the small chamber so as to cover the small chamber of the shield case 1. A bulging portion 9 is formed on the opposite side by press working.

To assemble the cover with the above configuration, insert the protrusions 4 of the shield case 1 into the slots 6 and 8 of the inner cover 5 and the outer cover 7 in that order on the open surface of the shield case 1.
The cover 7 is attached to the shield case 1 by inserting the cover 7 into the shield case 1. After that, the outer cover 7 and the inner cover 5 are attached to the shield case 1 by twisting the projections 4, and the part of the inner cover 5 located above the small chamber is pressed by the bulge part 9 of the outer cover 7. , the inner cover 5 is configured to abut against the end face of the partition plate 2 and the end face of the shield case side plate 3.

FIG. 2 shows a longitudinal sectional view after the inner cover 5 and outer cover 7 are attached to the shield case 1 through the above assembly. Note that an oscillation circuit section is assembled in the small chambers 10a and 10b (not shown).

In such a conventional shield case structure for high-frequency equipment, the inner cover 5 is interposed inside the outer cover 7, and the inner cover 5 is pressed against the end surface of the partition plate 2 by the bulge 9 of the outer cover 7. However, in such a configuration, the inner cover 5
Although it is pressed against the end surface of the partition plate 2, especially in CATV converters, the frequency of each circuit is extremely high and the signal level is large, so the partition plate 2
Signals leaked to other chambers through the end face of the tube, causing problems such as interference with transmission signals and generation of beats.

In addition, CATV that uses the double heterodyne system
The converter requires two local oscillator circuits, both of which have high frequencies.
Moreover, it has a very large signal level. Therefore, in order to prevent the interference of these frequency signals and the generation of beats due to mutual leakage, the frequency signals are placed in a small chamber at the outermost end of the shield case 1, as shown in Fig. 2. . However, even with this, leakage of those signals could not be sufficiently suppressed. The reason why such a problem occurs is that the inner cover 5 above the small chambers of both oscillation circuits is one cover and is formed integrally, so the oscillation signals of both are transmitted by the inner cover 5 and leakage occurs. It is considered that

The present invention has been developed in view of the above-mentioned conventional problems, and one embodiment of the present invention will be described below.

FIG. 3 shows an exploded perspective view of a shield case according to an embodiment of the present invention. In this figure, the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals, and the explanation thereof will be omitted. At the top of the end surface of the partition plate 2 that partitions the inside of the shield case 1, there is a rim 11 made integrally with the side plate 3.
is formed.

The inner cover 5, which is a conductive thin plate, is separated into two parts, left and right. This is the small chamber 10a and 10b in which the first local oscillation circuit and the second local oscillation circuit are assembled.
The inner cover 5 that covers the inside is separated into 5a and 5b. By covering each local oscillation circuit with separate inner covers 5a and 5b in this way, the above-mentioned problem of the conventional method using a single integrally formed inner cover 5 can be completely solved. It is possible.

FIG. 3 shows a longitudinal sectional view of the shield case shown in FIG. 2 with the inner cover 5 and outer cover 7 assembled. 12
indicates a printed circuit board.

As mentioned above, the structure of the shield case for high-frequency equipment according to the present invention is such that a wide edge is formed at the top of the cross section of the partition plate that partitions the inside of the shield case, an inner cover is placed on this, and an outer cover is placed on top of this. The structure is such that the inner cover is pressed against the wide edge by the bulge part of the outer cover that protrudes toward the small chamber, so that the contact between the inner cover and the partition plate is not in line with the conventional example. Because the surface is pressed against the wide edge rather than the end surface close to the
Since it was possible to prevent signal leakage to other compartmentalized small rooms, the shielding effect could be enhanced, and therefore signal interference and unnecessary beats could be prevented from occurring.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of a conventional shield case, Figure 2 is a vertical sectional view of the shield case in Figure 1,
FIG. 3 is an exploded perspective view of a shield case according to an embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of the shield case of FIG. 3. 1... Shield case, 2... Partition plate, 3...
Side plate, 4... projection, 5, 5a, 5b... inner cover, 6, 8... slot, 9... bulge, 10a, 1
0b...Small chamber where the local oscillation circuit is assembled, 11
...Edge, 12...Printed circuit board.

Claims (1)

[Scope of utility model registration request] The interior consists of a conductive shield case with a built-in high-frequency circuit, a partition plate forming a plurality of small chambers inside the shield case, and an elastic conductive thin plate placed so as to cover the open surface of the shield case. a cover, and an outer cover that is placed on the inner cover and has a bulge formed at a position facing a small chamber in the shield case, and the shield case and the outer cover are arranged on the end face of the partition plate on the inner cover side. formed in one piece,
A planar edge is arranged parallel to the inner cover and wider than the cross-sectional dimension of the partition plate, so that the inner cover located above the small chamber is connected to the small chamber of the outer cover. A shield case structure for high-frequency equipment, characterized in that an inner cover is pressed against an edge on an end face of the partition plate by pressing with a bulge that projects toward the other side.