JP3946381B2 - Electromagnetic wave shielding casing and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic wave shielding casing and a method for manufacturing the same, and in particular, chassis hair can be removed by molding a non-woven fabric such as metal having conductivity at the opening end of the casing.
[0002]
[Prior art]
Conventionally, various electromagnetic shielding cases have been proposed in which stamping molding is performed using a sheet material in which a conductive sheet is laminated at the center in the thickness direction of a synthetic resin-based sheet. Japanese Patent Laid-Open No. 5-315784 proposes a method for producing a harmful electromagnetic wave shielding molded article as an improvement in the earth function in order to improve the shielding effect of the harmful electric waves generated from the electromagnetic wave shielding casing. ing.
[0003]
4 to 5 are cross-sectional views of an electromagnetic wave shielding casing according to a conventional method for manufacturing an electromagnetic wave shielding molded article, and FIGS. 6 to 7 are perspective views of a sheet-like conductor used for the case. .
The purpose of this electromagnetic wave shielding casing is to provide excellent shielding against harmful electromagnetic waves and to provide grounding for the casing chassis.
[0004]
Next, a conventional electromagnetic wave shielding housing will be described with reference to FIGS. As shown in FIG. 4, the electromagnetic wave shielding casing 11 made of a sheet-like synthetic resin material is mounted on the front surface of the casing chassis 12 of the electronic device or the like.
The structure of the electromagnetic wave shielding casing 11 includes a sheet-like conductor 14 that is processed to be uneven and has flexibility. Further, as shown in FIG. 5, the convex-concave sheet-like conductor 14 can be grounded simply by fixing the convex shape 14a on the inner side surface of the apparatus and fixing it with the housing chassis 12 and the screw 13.
[0005]
In addition, the uneven sheet-like conductor 14 is made of a material including a metal such as copper, aluminum, and stainless steel having good conductivity, carbon fiber, and the like. In addition, since the uneven sheet-like conductor 14 is stretched during molding such as heat molding, it is necessary to have stretchability that can be extended following the molding. The stretch ratio of the sheet-like conductor is about 1.1 to 2 times in the shallow part and about 3 to 4 times in the deep part. Therefore, considering this point, the stretchability of the sheet-like conductor is given.
[0006]
Further, as a method of interposing the uneven sheet-like conductor 14 in the sheet-shaped synthetic resin molding material, a method of heating or ultrasonic welding at the time of lamination, a method of adhering with an adhesive, and sandwiching at the time of sheet extrusion molding A method is mentioned. At this time, the synthetic resin material located on both sides is formed by using the sheet conductor 14b having holes in a staggered pattern as shown in FIG. 6 and the mesh-like sheet conductor 14c of the metal fiber in FIG. In this case, it is preferable that it is partially melted and integrated, and the strength between layers of the molded product is improved. The thickness of the sheet-like synthetic resin material is about 2 to 10 mm.
[0007]
[Problems to be solved by the invention]
However, in the electromagnetic wave shielding housing configured as described above, in order to form a sheet-like synthetic resin molding material provided with the uneven sheet-like conductor 14, for example, a sheet conductor having holes in a staggered pattern is used. 14b or the metal fiber mesh sheet-like conductor 14c has to be processed into an uneven shape in advance, and such a synthetic resin-based conductive sheet is a special form, which increases the cost. There was a point.
Further, in order to integrate the uneven sheet-like conductor 14 with the sheet-like synthetic resin molding material, a method of heating or ultrasonic welding during lamination, a method of adhering with an adhesive, a sandwich at the time of sheet extrusion molding However, when the sheet-shaped synthetic resin molding material selected by these methods is stamped and formed into a casing, the convex portions of the sheet-shaped conductor 14 are not exposed to the surface completely and are completely There was also a problem that the earth could not be taken. In addition, there is a problem that the sheet-like conductor 14 is not easily stretched when it is shaped into a box shape, so that it is broken or wrinkled.
[0008]
[Means for Solving the Problems]
When stamping an electromagnetic wave shielding casing using a commercially available inexpensive synthetic resin-based conductive sheet, the present invention can remove the chassis hair by forming and molding a metal nonwoven fabric at the opening end of the casing. An object of the present invention is to provide an electromagnetic wave shielding casing and a manufacturing method thereof.
[0009]
That is, in the first invention of the present application, when the opening end portion of the electromagnetic shielding case formed using the synthetic resin conductive sheet 1a is stamped, the opening end portion of the case 1 has conductivity. An electromagnetic wave shielding housing in which a non-woven fabric 2 made of metal or the like is integrally provided so that chassis hair can be removed at a portion of the non-woven fabric 2 made of metal or the like.
[0010]
Further, in the second invention, when the electromagnetic shielding casing is stamped by using the synthetic resin conductive sheet 1a, the synthetic resin conductive sheet 1a is disposed in the mold and the conductivity is improved. Inserting a non-woven fabric 2 made of metal or the like, stamping molding in a state in which the synthetic resin-based conductive sheet 1a and the non-woven fabric 2 made of metal or the like are heated, and forming the non-woven fabric 2 made of metal or the like at the opening end of the housing 1 Is formed integrally, and the chassis hair can be removed at the portion of the non-woven fabric 2 made of metal or the like.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of an electromagnetic wave shielding casing of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG.
In the electromagnetic wave shielding casing of the present invention, a conductive nonwoven fabric 2 or the like is integrally provided at the opening end of the casing 1 formed by stamping a synthetic resin conductive sheet 1a. The chassis hair can be removed at the non-woven fabric 2 portion.
[0012]
The synthetic resin-based conductive sheet (1a) is a thermoplastic sheet in which long fibers such as metal are dispersed.
[0013]
The non-woven fabric 2 made of metal or the like may be in the form of a sheet obtained by needling and pressing fibers of a thread-like metal or the like, or may be bundled in a cage shape.
[0014]
FIG. 3 is a longitudinal sectional view of a mold used in the present invention, where (A) shows a state before molding and (B) shows a state after molding.
The core mold (lower mold) 3 formed in a convex shape is provided with a groove 3b for fitting a metal nonwoven fabric into the root portion of the convex portion 3a, and the metal nonwoven fabric 2 of the previous period is inserted into the groove 3b. It has become. A plurality of needles 3c for holding a conductive sheet are implanted on the upper surface of the convex portion 3a. Reference numeral 4 denotes a cavity mold (upper mold) formed in a concave shape.
[0015]
Next, the manufacturing method of the electromagnetic wave shielding housing according to the present invention will be described.
(1) A sheet or bundle of metal nonwoven fabric is inserted into the groove 3b of the core mold 3, and a synthetic resin conductive sheet is disposed on the upper surface of the convex portion a. (2) Next, the mold (upper mold) is lowered, and the synthetic resin conductive sheet and the metal nonwoven fabric are heated and stamped to form the casing. A metal nonwoven fabric is integrally formed at the opening end.
[0016]
【The invention's effect】
The present invention relates to an electromagnetic shielding case in which a non-woven fabric such as metal is formed by insert molding at the opening end of the case when stamping the electromagnetic shielding case using an inexpensive synthetic resin-based conductive sheet, and a method for manufacturing the electromagnetic shielding case Therefore, it is possible to reliably remove the chassis hair at a low cost.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electromagnetic wave shielding casing of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a longitudinal sectional view of a mold used in the present invention.
FIG. 4 is a cross-sectional view of a conventional electromagnetic shielding housing.
FIG. 5 is an enlarged cross-sectional view of a portion B in FIG.
FIG. 6 is a perspective view of a conventional sheet-like conductor.
FIG. 7 is a perspective view of another conventional sheet-like conductor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Case 1a Conductive sheet 2 Non-woven fabric made of metal 3 Core mold 3a Convex part 3b Groove 3c Needle 4 Mold type

Claims (2)

Synthetic resin-based conductive sheet (1a) in stamped electromagnetic shielding enclosure formed by the housing (1) of metallic having conductivity only in the opening end portion of the nonwoven fabric (2) integrally An electromagnetic shielding housing characterized by being provided. In the method of manufacturing an electromagnetic wave shielding casing formed by stamping the synthetic resin-based conductive sheet (1a), the synthetic resin-based conductive sheet (1a) is disposed in a mold in a heated state. housing while heating the metallic nonwoven fabric (2) having conductivity inserted into the open end of (1), metallic having conductivity only at the open end of the stamping to a housing (1) The manufacturing method of the electromagnetic wave shielding housing | casing characterized by integrally shape | molding the nonwoven fabric (2).

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