JPH0225280Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic shielding case used to cover electrical equipment, parts, elements, etc. that require electromagnetic shielding, such as high frequency transformers. Conventionally, such electromagnetic shielding cases have generally been made of metal plates made of aluminum, brass, etc., mainly by drawing process. The drawback is that it is difficult to precisely create the unevenness necessary for attaching electrical equipment and parts to the case itself, as well as the unevenness necessary for attaching the electrical equipment and parts to the outside of the case. Since the case itself is conductive, there is also the problem that electrical insulation from internal components and other components must always be considered.

The main purpose of this invention is to construct a shielding case with the required electromagnetic shielding performance using only a synthetic resin layer, in order to improve the problems of metal cases, and to eliminate the necessary recesses inside and outside the case. and convex parts,
Alternatively, it is possible to precisely form holes, etc., and to provide complete electrical insulation from internal and external electrical equipment and parts.

The shield case of the present invention is made by stacking three or more thermoplastic resin layers and integrally molding them into the desired shape using injection, extrusion, etc. Molded by stacking an inner layer 1, a core layer 2, and an outer layer 3 made of resin,
The core layer 2 in this is made of a conductive resin with electromagnetic shielding performance. In addition, the inner layer 1 is made of high-performance engineering plastic with appropriate mechanical, chemical, and electrical performance, or equivalent performance, depending on the performance, shape, etc. of the electrical equipment and parts stored in the case. Thermoplastic resins are suitable.

Furthermore, the outer layer 3 must meet the general requirements for exterior materials such as beauty, resistance to scratches, good insulation, etc., as well as the location where the electrical equipment, parts, etc. are installed, the environment in which it is used, and other usage conditions. Appropriate materials are selected each time depending on the situation.

The shape of the case itself may be a box shape with one opening as shown in Figures 1 to 3, a cylindrical or pipe shape as shown in Figures 4 to 5, or a shape as shown in Figures 6 to 7. It can be formed into various shapes, such as a gutter-like shape as shown in Figure 5, but inside the convex body 5 can be formed into various shapes necessary for attaching electrical equipment, parts, etc. to be stored or for reinforcement. , recesses, holes, etc. are provided, and protrusions 5, recesses, reinforcing ribs, etc. necessary for holding the case itself from the outside or attaching other parts etc. are arbitrarily formed on the outside. be able to.

Usually, one layer each for the inner layer, core layer, and outer layer is sufficient, but if necessary, each layer can be composed of more layers as illustrated in FIG. 9. For example, in the case of the inner layer, when a special resin such as glass fiber-containing resin is used for the innermost first inner layer 1, the second inner layer is used to improve adhesion and weldability with the core layer 2. 1' and may even require a third inner layer. Additionally, multilayer molding (composite molding) may be required due to requirements such as connection with electrical equipment and parts housed within the case. In the case of the core layer, when the electromagnetic shielding performance of the conductive resin is insufficient, even if you try to increase the thickness of the layer, there is a limit due to restrictions on the molding method, so several core layers can be stacked to achieve the required shielding. Performance may have to be achieved. FIG. 9 shows an example in which two core layers, a first core layer 2 and a second core layer 2', are provided, with an intermediate layer 6 interposed between them.

This intermediate layer 6 may be made of the same material as, for example, the layer closest to the inner layer (second inner layer 1' in FIG. 9) or the first outer layer 3, or other special materials may be used.

For the outer layer, a plurality of layers are often provided by a two-color molding method or the like from a design standpoint or for identification purposes. FIG. 9 shows an example in which a pattern 7 is provided on the first outer layer 3 and this pattern 7 is exposed on the outer surface of the second outer layer 3' by a two-color molding method. Note that in order to connect the core layer to the ground, a part of the core layer (connection part) may be exposed to the outside. For example, the connecting portion may be formed without being covered with the outer layer, or a portion of the core layer may be provided with a convex portion, and only this convex portion may be exposed on the surface of the outer layer.

When selecting the material for each layer, it is necessary to consider the injection and extrusion fusion properties (weldability) between the materials of each layer, depending on the use of the case, so that materials with good fusion properties are adjacent to each other as much as possible. However, it is effective to increase the interlayer peeling strength by adding irregularities such as ribs and grain patterns to the adjacent surfaces of each layer.

The shield case according to the present invention is composed of three or more synthetic resin layers as described above, and since the core layer is made of conductive resin, it has an electromagnetic shielding effect, and the shield case is inherently can achieve the objectives of Also, inside and outside,
It has the advantage of being able to accurately and easily form various shapes of protrusions, recesses, ribs, etc. required for attaching electrical equipment, parts, etc. to be stored. In addition, since electrical insulation is ensured by the inner and outer layers, there is no need to consider insulation from other components when mounting on printed circuit boards, etc.
Wiring is easier to handle. Furthermore, depending on the outer layer, various design elements such as external shape, pattern, and color can be freely selected, and corrosion resistance is also superior to that of metal cases.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a shield case according to the present invention, and FIGS. 2 and 3 are respectively shown in FIG.
4 is another embodiment, FIG. 5 is a view in the V direction of FIG. 4, FIG. 6 is another embodiment, and FIG. 7 is a view in the direction of the arrows in FIG. The figure is also an arrow view,
FIG. 9 shows an example in which there are three or more layers. In the figure, 1, 1'... inner layer, 2, 2'... core layer, 3, 3'... outer layer, 4... convex body, 5... convex body,
6...middle layer, 7...pattern.

Claims (1)

[Scope of utility model registration request] A synthetic resin electromagnetic product made by integrally molding one or more core layers made of conductive resin with electromagnetic shielding performance, and inner and outer layers made of one or more synthetic resins stacked on the inside and outside of the core layer. shield case.