JPH06226776A - Manufacture of housing with electromagnetic wave shielding function - Google Patents

Abstract

PURPOSE:To extend or expose a metal gauze out of a housing without generating a flash at an end, a vent hole, etc., of the housing by disposing the gauze in a pair of molds, locally sandwiching the gauze between the pair of the molds when the housing integral with the gauze is molded, and so forming at least one surface of sandwiching parts of the molds as to be softer than the gauze. CONSTITUTION:Molds has a lower mold 2 and an upper mold 1 having a design surface, and slide cores 3 driven to approach the vertical walls 21 of the mold 2 from four directions are disposed oppositely to the vertical walls 21. A soft part 30 is formed, for example, of fluorine rubber on an end surface of each core 3. A metal gauze 4 of copper is so disposed as to be located along the surface of the mold 2, and its end is sandwiched between the core 3 and the surface 21 of the mold 2. The gauze 4 is buried in the part 30, and liquidtightly sandwiched. Then, a predetermined quantity of melt resin is cast in a cavity, and compression-molded by the molds 1, 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for housing an electric / electronic device susceptible to electromagnetic interference or an electric / electronic device that emits an electromagnetic wave and manufacturing a housing having an electromagnetic wave shielding function for preventing the electromagnetic interference.

[0002]

2. Description of the Related Art As a general method for preventing electromagnetic interference, an article susceptible to interference or an article emitting electromagnetic waves may be surrounded by a conductor plate kept at a constant potential.
This makes it possible to electromagnetically shield the inside and the outside surrounded by the conductor plate. In the usual case, without using a conductor plate, it is possible to sufficiently weaken the influence of the electric field to the inside by surrounding it with a conductive wire mesh formed of copper or aluminum.

However, if it is simply surrounded by a wire mesh, the article inside can be seen through the wire mesh, which is not preferable in terms of design and has a problem in strength. Therefore, it has been considered to form a housing in which a wire net is embedded from a resin and to store the article in the housing. For example, Japanese Patent Application Laid-Open No. 4-113819 discloses a manufacturing method of a parabolic antenna, which is not a housing, but has a sheet having an electromagnetic reflection layer arranged in a mold and injection compression molded.

[0004]

When a box-shaped housing contains an article that is susceptible to damage or an article that emits electromagnetic waves, a method of forming a hermetically sealed container with a pair of box-shaped housings and housing it inside is considered. To be However, in this case, it is necessary to set the wire nets in the respective housings to the same potential, and the pair of wire nets must be electrically connected to each other. For that purpose, it is most convenient to extend the end of the wire netting from the edge of the box-shaped housing to the outside and connect the ends.

By the way, when the wire nets are arranged in a pair of molds and integrally molded, there is a method of holding the end parts of the wire nets by the molds in order to prevent the resin from adhering to the end parts of the wire nets. However, since the wire mesh is hard, a gap corresponding to the thickness (t) of the wire mesh is formed as shown in FIG. 6, and resin is likely to penetrate into the gap to cause burrs, resulting in a defective product. Also,
When the articles housed in the housing generate heat, it is necessary to provide ventilation holes in the housing to facilitate heat dissipation. However, in order not to impair the electromagnetic shield function,
It is necessary to leave a wire mesh also in the ventilation hole. In this case as well, a method may be considered in which the wire mesh is sandwiched between the vent holes in the same manner as described above, but the resin may still enter through the gap corresponding to the thickness of the wire mesh, and burrs may occur.

Because of the fear of occurrence of the above-mentioned problems, conventionally, a case in which a wire net is extended has not been manufactured, but a shield layer is formed on the surface of the case by coating with a conductive paint or a vacuum deposition method. The electromagnetic wave shielding function is given by that. According to this method, the conduction between the housings is ensured by the structure in which the shield layers are in close contact with each other, and the shielding function such as the ventilation hole can be formed by attaching a wire mesh which is a separate component. However, in these methods, the formation of the housing and the formation of the pattern are separate steps, and the man-hours and raw material costs are large, resulting in a cost problem.

The present invention has been made in view of the above circumstances. The metal mesh is placed in a pair of molds to integrally mold the housing, and the metal mesh is formed without burrs at the ends of the housing and the vent holes. The purpose is to extend or expose to the outside of the housing.

[0008]

A method of manufacturing an enclosure having an electromagnetic wave shielding function according to the present invention which solves the above-mentioned problems is an enclosure having an electromagnetic wave shielding function composed of a housing-shaped resin main body and a wire mesh embedded in the main body. Is a method of manufacturing by arranging a wire mesh in a pair of molds and integrally molding, wherein the wire mesh is locally clamped by a pair of molds, and a part of the portion that clamps the wire mesh of a pair of molds is At least one of the surfaces is softer than the material of the wire mesh.

[0009]

In the manufacturing method of the present invention, at least one surface of the pair of molds for sandwiching the wire net is made softer than the material of the wire net. Therefore, when the wire net is clamped, the soft part is pressed and deformed by the wire net, and the wire net is buried in the soft part. Therefore, the contact area of the soft part with the surface of the other mold increases, so that the resin can be prevented from entering during molding, burrs are not generated, and a housing having a good appearance quality can be formed.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. Figure 1
2 shows the mold used in this example. This die forms a box-shaped housing, and is composed of an upper die 1, a lower die 2 and a slide core 3. The upper mold 1 constitutes a concave mold having a mold surface 10 forming a design surface, and the lower mold 2 comprises a mold surface 2
A convex type having 0 is constructed. And the vertical mold surface 2 of the lower mold 2.
The slide cores 3 are arranged so as to be capable of driving close to each other from four sides so as to face 1. A soft portion 30 made of fluororubber ("Viton" manufactured by DuPont) is formed on a portion of the tip surface of each slide core 3 having a thickness of 5 to 15 mm. Further, each slide core 3 is connected to a cylinder device (not shown).

Using this mold, a box-shaped housing was formed as follows. First, the metal wire net 4 made of copper formed in advance along the mold surface shape of the lower mold 2 is arranged on the mold surface of the lower mold 2.
Next, the slide core 3 is driven forward, and the end of the wire net 4 is sandwiched between the slide core 3 and the vertical mold surface 21 of the lower mold 2. At this time, the soft part 30 of the slide core 3 comes into contact with the wire net 4, but the soft part 30 is deformed because it is softer than the wire net 4, and the wire net 4 is buried in the soft part 30 as shown in an enlarged view in FIG. It becomes a state. Therefore, the soft part 30 is in close contact with the lower mold 2,
There is no gap as in the past.

In this state, a predetermined amount of molten resin is injected into the cavity, the upper mold 1 and the lower mold 2 are driven close to each other, and compression molding is performed. Since the end portion of the wire net 4 is liquid-tightly sandwiched between the soft portion 30 and the vertical mold surface 21 of the lower die 2, the molten resin is prevented from entering the sandwiched portion and burr is prevented from occurring. After the molten resin is solidified, the upper mold 1 and the lower mold 2 are opened, the slide core 3 is retracted, and the housing, which is a molded body, is released. A sectional view of the obtained housing is shown in FIG. The housing has a box shape, and the wire netting 4 is exposed and extends from the peripheral edge portion of the opening. No burr due to resin squeeze is seen at the peripheral edge of the opening, and the appearance is good.

This housing is used as a pair of two, and the wire nets 4 that are exposed with their peripheral portions facing each other are connected and used. Here, in order to reliably connect the wire nets to each other, the structure shown in FIG. 5 is preferable.
That is, the rib 50 having the first taper surface 51 protruding toward the inner peripheral side is formed on one housing 5, and the end portion of the other housing 6 has a stepped structure, and the second taper surface 6 is formed on the inside.
1 is formed. Then, by inserting the other housing 6 into the one housing 5 so as to sandwich the pair of wire nets 4 extending outward from the opening peripheral portions of both the housings, the joining of the first taper surface 51 and the second taper surface 61 is achieved. Thus, both wire nets 4 can be reliably connected.

[0014]

That is, according to the method for manufacturing a casing having an electromagnetic wave shielding function of the present invention, even if the metal mesh is integrally formed by disposing the metal mesh in the mold, the metal mesh can be formed without burrs at the ends of the casing and the vent holes. It can be extended or exposed to the outside of the housing. Therefore, the number of steps can be remarkably reduced and the cost can be remarkably reduced as compared with the conventional method of providing the shield function with a conductive paint or vacuum deposition.

[Brief description of drawings]

FIG. 1 is a sectional view of a mold used in an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a molded body and a mold after completion of compression molding in one embodiment of the present invention.

FIG. 3 is an explanatory cross-sectional view showing a state where a wire mesh is sandwiched by slide cores in an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a housing obtained in an example of the present invention.

FIG. 5 is an explanatory cross-sectional view showing an example of a connection structure for housings obtained by the manufacturing method of the present invention.

FIG. 6 is an explanatory cross-sectional view showing a state in which a wire net is sandwiched between conventional dies without using the manufacturing method of the present invention.

[Explanation of symbols]

1: Upper mold 2: Lower mold
3: Slide core 4: Wire mesh 21: Vertical surface 3
0: Soft part

Claims (1)

[Claims] 1. A method for producing a casing having an electromagnetic wave shielding function, which comprises a casing-shaped resin main body and a wire net embedded in the main body, by arranging the wire net in a pair of molds and integrally molding the same. The wire mesh is locally clamped by a pair of molds, and at least one surface of a portion of the pair of molds that clamps the metal mesh is softer than the material of the metal mesh. A method of manufacturing a housing having an electromagnetic wave shielding function.