JPH0577358B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In a shield case that electrically shields electronic components mounted on a printed board from external electronic components, the printed board is attached to the upper case in order to increase the component mounting space on the internal printed board. and the lower case in a sandwich-like manner, and
The structure is such that the upper case and the lower case are tightened at two places.

[Industrial application field]

The present invention relates to the structure of a shield case that electrically shields electronic components mounted on a printed board from external electronic components.

[Conventional technology]

Conventional shield cases of this type generally have a structure in which a printed circuit board 1 is completely enclosed by upper and lower cases 2 and 3, as shown in FIG. In FIG. 6, 1 is a printed board on which electronic components (not shown) are mounted, 2 is an upper case, 3 is a lower case,
4 is a screw that fixes the printed board 1 to the inside of the lower case 2, and 5 is a screw that fixes the upper case 2 to the lower case 3. In this way, the printed circuit board 1 had a structure in which it was completely covered by the inside of the case defined between the upper case 2 and the lower case 3.

[Problem that the invention seeks to solve]

The conventional shield case as shown in Figure 6 is
Since the printed board 1 is completely covered inside the case between the upper case 2 and the lower case 3, it is necessary to have a sufficient internal space commensurate with the size of the printed board 1. Furthermore, since the printed board 1 had to be fixed inside the lower case 3, there were many screw attachment points, and a considerable area was required to fix the printed board 1 itself with the screws 4. Therefore, the space for mounting components on the printed board 1 is also limited.

[Means for solving problems]

In order to solve these problems, according to the present invention, the periphery of the printed board is sandwiched between an upper case and a lower case that have an electromagnetic shielding function, and partition plates are provided inside the upper case and the lower case, respectively. The partition plates are arranged so that they face each other with the printed board in between and form a slight gap between them and the printed board in an unfastened state, and are located approximately in the center of the upper case and the lower case. There is provided a shield case structure, characterized in that the upper case and the lower case are tightened by screws passing through the partition plate and the printed board to such an extent that the gap is almost eliminated.

[Effect]

When the upper case and the lower case are tightened with screws, the periphery of the printed board is firmly sandwiched between the upper case and the lower case, and the gap between the partition plate and the printed board disappears, and the partition plate is printed. By contacting the boards, the printed board is also clamped between the partition plates. The printed board can be used as an effective space over almost the entire area inside the case, except for the part that contacts the partition plate.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a sectional view showing an embodiment of the shield case of the present invention, Fig. 2 is a plan view of the same embodiment, Fig. 3 is a sectional view at - in Fig. 1, and Fig. 4 is an enlarged view of the shield braided wire. 5 is an enlarged sectional view of the portion indicated by V in FIG. 1.

The printed board 10 has a component mounting surface 11 on its upper surface and a wiring diagram 12 on which a pattern is formed on its lower surface. Although not shown, various electronic components are mounted on the component mounting surface 11.

The upper case 20 and the lower case 30 are each made of aluminum or aluminum alloy die casting and have an electromagnetic shielding function. The upper case 20 consists of an upper wall part 21 and a peripheral wall part 22,
Several partition plates 23 extending downward from the upper wall portion 21 are formed inside. Furthermore, boss portions 24 are formed at one or two locations (in the embodiment, one location) in the center for passing through screws 15 extending downward from the upper wall 21. The partition plate 23 extends from the boss portion 24, and there are some partition plates 23a that extend to the peripheral wall portion 22 and some partition plates 23a that extend only halfway.

Although the lower case 30 is not as tall as the upper case 20, it is composed of a lower wall portion 31 and a peripheral wall flange portion 32, and a partition plate or rib 33 is formed inside thereof opposite to the partition plate 23 of the upper case 20. has been done. Also, the boss part 2 of the upper case 20 is also located in the center part.
A boss portion 34 having a tapped hole for screwing the through screw 15 is formed at a position corresponding to 4. Similarly, a partition plate or rib 33 extends from this boss 34.

A groove 35 for inserting the shield braided wire 40 is formed in the peripheral wall flange portion 32 over almost the entire circumference or main part of the case, and the shield braided wire 40 is inserted into this groove. As shown in FIG. 4, the shield braided wire 40 is made by braiding and winding a shielding metal wire 42 around a hollow elastic body 41 such as rubber.

The peripheral edge of the printed board 10 is connected to the peripheral wall 22 of the upper case 20 and the lower case 3 with the shield braided wire 40 in between.
It is sandwiched between the peripheral wall flange 32 of 0 and the peripheral wall flange 32 of 0 in a sandwich shape. Between the partition plate 23 (including the boss portion 24) of the upper case 20 and the printed board 10, and between the partition plate or rib 33 (including the boss portion 3) of the lower case 30.
4) and the printed board 10. When the through screw 15 is not tightened, there is a slight gap (for example, 0.1 to 0.2 mm) between the through screw 15 and the printed board 10.
There are gaps 26, 36 (about 100 degrees). These gaps 2
Only one of 6 and 36 may be used.

Then, the through screw 15 is inserted into the boss part 24 of the upper case 20, and screwed into the tap of the boss part 34 of the lower case 30 through the corresponding hole in the printed board 10 and tightened. At this time, the peripheral edge of the printed board 10 is strongly sandwiched between the peripheral wall 22 of the upper case 20 and the peripheral wall flange 32 of the lower case 30, and the gap 2 between the partition plates 23, 33 and the printed board 10
6, 36 are almost gone, and the partition plates 23, 33
contacts the printed board 10, and the printed board is also tightened between the partition plate 23 (including the boss portion 24) and the partition plate 33 (including the boss portion 34).

In this case, for example, a suitable leaf spring 28 is inserted into the gap 26 between the partition plate 23 and the printed board 10, and the printed board 10 is held by this leaf spring 28 when the through screw 15 is tightened. It's okay.

The four corners of the upper case 20 and the lower case 30 are fixed to each other by fixing screws 16 passing through the printed board 10, as shown in FIG. As shown in FIG. 5, grounding patterns 14 are formed on both sides of the peripheral edge of the printed board 10, and the patterns 14 on both sides are connected to each other via through holes 13. Thereby, the ground of the printed board 10 is connected to the upper case 20 and the lower case 30. Furthermore, when tightening, the shield braided wire 40 bends within the groove 32 so that its cross section becomes elliptical, thereby ensuring leakage prevention.

Furthermore, because the printed board 10 is pressed against the peripheral edge 22 of the upper case due to the elasticity of the shield braided wire 40, the peripheral edge 22 comes into contact with the printed board 10, thereby ensuring reliable shielding at this portion.

[Effects of the Invention] As described above, according to the present invention, the printed board 10 is connected to the upper case 20 and the lower case 3 with a simple structure.
Can be held between 0 and printed board 10
Since almost the entire surface of the substrate except for the portions that contact the partition plates 23 and 33 can be used as the component mounting surface 11 or the wiring surface 12, the mounting efficiency of the printed circuit board can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the shield case of the present invention, Fig. 2 is a plan view of the same embodiment, Fig. 3 is a sectional view at - in Fig. 2, and Fig. 4 is an enlarged view of the shield braided wire. 5 is an enlarged sectional view of the portion indicated by V in FIG. 1, and FIG. 6 is a sectional view of a conventional shield case. 10...Printed board, 15...Through screw, 20
... Upper case, 23 ... Partition plate, 30 ... Lower case, 33 ... Partition plate, 40 ... Shield braided wire.

Claims (1)

[Claims] 1 The periphery of the printed board is sandwiched between an upper case and a lower case that have an electromagnetic shielding function, and a partition plate is provided inside each of the upper case and lower case, and the partition plates face each other with the printed board in between and are non-contact. A slight gap is formed between the upper case and the printed board in the tightened state, and a screw located approximately at the center of the upper case and the lower case and passing through the partition plate and the printed board is used to close the gap. This shield case structure is characterized by an upper case and a lower case being tightened to the extent that there is almost no loss.