JPH06216791A - Manufacture of shielded structure - Google Patents

Abstract

PURPOSE:To manufacture a shielded structure with satisfactory strength and shieldability and without generating dead space in the inside by using a fixed type metallic mold. CONSTITUTION:A side plate 13 is arranged successively on a ceiling plate 12 and the four peripheral edges of it by using a metallic plate, and an inward tongue piece 14 which supports a printed circuit board on the side plate 13, and a projection 15 protruding to the outside on the upper part of the tongue piece 14 are provided, and the shielded structure 11 is formed by bending the ceiling plate 12 and the side plate 13 at right angles at the part of the projection 15. The bending of the ceiling plate 12 and the side plate 13 is performed by using the fixed type metallic mold in which an escape part is provided at a position corresponding to the tongue piece 14 along the upward/downward direction, and applying press working, which enables a parting mold to be formed by using the fixed type metallic mold. Also, since no window hole is required on the shielded body structure, the strength and the shieldability can be improved, and since the projection 15 is swollen out to the outside, the dead space in the inside can be prevented from being formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a shield structure used as a case for high frequency equipment such as a tuner.

[0002]

2. Description of the Related Art As shown in FIG. 9, a conventional shield structure 1 uses a single metal plate, and a side plate 3 facing downward is bent at a right angle by press forming on four peripheral edges of a top plate 2 of a rectangular frame. Then, the adjacent end portions of the side plates 3 are assembled together by assembling, and the tongue piece 4 for supporting the printed circuit board is provided on the side board 3 so as to face inward, and the top plate 2 and the side board 3 are provided above the tongue piece 4. It has a structure in which a window hole 5 is provided in the bent portion.

By the way, the shield structure 1 as described above is used.
Must be processed so that the top plate 2 and the side plate 3 are bent at a right angle, and the setting of the window hole 5 is advantageous for this bending.

That is, as shown in FIG. 10, when the metal plate is bent at the upper position of the tongue 4 into the top plate 2 and the side plate 3 by press working without providing the window hole in the metal plate, as shown in FIG. A movable structure must be adopted for the mold 6 that receives the insides of the top plate 2 and the side plate 3.

Because the tongue piece 4 is provided on the side plate 3 so as to project inward, the tongue piece 4 is pulled by the die when the die is released from the fixed mold, and the die cannot be released. Therefore, the movable mold 6 must be used.

However, the movable mold 6 has a problem that the structure becomes complicated and the price of the mold becomes expensive.

Therefore, as shown in FIG. 12, a fixed mold 8 having a vertical escape portion 7 at a corresponding position of the tongue piece 4.
Although it is conceivable that the top plate 2 and the side plate 3 are bent using this, when this mold 8 is used to perform the bending process, the portion provided with the escape portion 7 is located at the bending position of the top plate 2 and the side plate 3. It is not possible to support the inside, which is why FIG.
As shown in FIG. 14, the tongue piece 4 is formed at the bent portion of the top plate 2 and the side plate 3.
The inwardly protruding sag 9 and the deformed portion 10 of the top plate 2 occur at the upper position of the.

In particular, the sag 9 projects inside the shield structure and becomes a dead space inside, which may cause interference with the components mounted on the printed circuit board and reduce the accuracy of the shield structure.

However, as shown in FIG. 9, if the window hole 5 is provided in the upper portion of the tongue piece 4, the metal plate does not exist in the upper portion of the tongue piece 4 when the top plate 2 and the side plate 3 are bent. Bending can be reliably performed using such a fixed mold 8, and it is not necessary to use a movable mold.

Therefore, it is effective to provide the window hole 5 in the metal plate in order to reduce the die cost and improve the accuracy of the shield structure.

[0011]

However, when the window hole 5 is provided in the shield structure, the strength of the shield structure is reduced and the shielding property of the electronic circuit is deteriorated, which adversely affects the performance of the electronic device. There is a problem that there is.

Therefore, in order to solve the above-mentioned problems, the present invention uses a fixed mold to manufacture a shield structure with high accuracy and without lowering the strength and shield property, and without damaging the internal space. The object is to provide a manufacturing method capable of

[0013]

In order to solve the above problems, according to the present invention, a protrusion bulging outward is provided on the upper side of the position where the tongue of the metal plate is made, and this protrusion is provided. This method employs a method of bending a metal plate into a top plate and a side plate at the position of a part.

[0014]

[Function] When the metal plate is bent to the top plate and the side plate at the position of the protrusion provided on the metal plate, the protrusion originally protrudes outward, so that the protrusion does not sag inward.
There is no dead space inside, and the top and side plates can be bent using a fixed mold.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is a development view of a metal plate used for the shield structure. Side plates 13 are provided on four peripheral edges of the frame-shaped top plate 12, and tongues 14 for supporting the printed circuit board on the side plates 13 are provided. Protrusions 15 are provided at positions corresponding to the bent portions of the top plate 12 and the side plate 13 slightly above the tongue piece 14.

As shown in FIGS. 3 to 6, the tongue piece 14 is formed by bending a portion surrounded by an upward U-shaped cut on a metal plate toward the inner surface side of the metal plate, and a projection 15 Is longer than the tongue piece 14 and is formed in a rectangular shape that bulges toward the outer surface side of the metal plate.

In order to fold the metal plate into a shield structure, as shown in FIG. 7, a fixed mold 8 having a vertical escape portion 7 on the side surface at a position corresponding to the tongue piece 14 is used. When the top plate 12 is placed on the mold 8 and is pressed and held, the surrounding side plates 13 are bent by press work so as to overlap with the side faces of the mold 8.
The shield structure 11 shown in FIG. 1 in which 3 is bent at a right angle is obtained.

By bending the side plate 13, the tongue piece 14 is housed in the escape portion 7, and the shield structure 11 for the die 8 is formed.
Can be removed from the mold without any problem.

When bending the top plate 12 and the side plate 13,
The upper end of the escape portion 7 of the mold 8 faces the inside of the protrusion 14, but the protrusion 15 is also bent by bending the top plate 12 and the side plate 13.

At this time, since the projection 15 is bulged outward in advance, the projection 15 bends inward as shown in FIGS. 7 and 8 without sagging, and is dead inside the shield structure 11. No space is generated.

As shown in FIG. 1, the completed shield structure 11
Since there is no window hole in the upper part of the tongue piece 14, the strength is not reduced, the shield property is good, the dead space is not generated inside, and the accuracy is improved.

In the illustrated embodiment, the tongue piece 1 is previously attached to the metal plate.
Although the example in which the bending process is performed in the state where the No. 4 and the protrusion 15 are formed is shown, the tongue piece 14 may be formed on the side plate 13 when the side plate 13 is bent.

Further, in the case of FIG. 1, the shield structure 11 is
Although an example in which the top plate 12 is formed in a frame shape and the opening 16 is provided in the center is shown, the top plate 12 may have a structure in which the entire surface is closed,
Further, the tongue piece 14 is provided at each of the side plates 13 of the shield structure 11 at one location, but the number and position of the tongue pieces 14 that can support the printed circuit board may be freely selected.

[0025]

As described above, according to the present invention, the protrusion bulging outward is provided above the tongue provided on the metal plate, and the top plate and the side plate are bent at the protrusion. Therefore, the shield structure can be manufactured using the fixed mold without providing a window hole in the bent portion, and the mold price can be reduced.

Further, since it is not necessary to provide a window hole in the shield structure, it is possible to obtain a shield structure in which the strength is not lowered and the shield property is good.

Further, after the bending process, the projection portion does not project inside the shield structure, no dead space is generated inside, and a highly accurate shield structure can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a shield structure manufactured by the method of the present invention.

FIG. 2 is a development view of a metal plate.

FIG. 3 is a perspective view showing a main part of a metal plate.

FIG. 4 is a plan view showing a main part of a metal plate.

5 is a cross-sectional view taken along the arrow VV of FIG.

FIG. 6 is a front view showing a main part of a shield structure formed by bending a metal plate.

7 is a cross-sectional view taken along the arrow VII-VII in FIG.

FIG. 8 is a perspective view showing a main part of a shield structure.

FIG. 9 is a perspective view showing a conventional shield structure.

FIG. 10 is a perspective view showing a conventional shield structure that is bent without a window hole.

FIG. 11 is a cross-sectional view showing the same bending process as above.

FIG. 12 is a perspective view of a main part showing a fixed mold.

FIG. 13 is a cross-sectional view showing a bending state of the shield structure using the same as above.

FIG. 14 is a perspective view showing a conventional shield structure that is bent according to FIG.

[Explanation of symbols]

 11 Shield structure 12 Top plate 13 Side plate 14 Tongue piece 15 Protrusion

[Procedure amendment]

[Submission date] September 9, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

FIG. 11

[Fig. 12]

[Fig. 13]

FIG. 14

Claims (1)

[Claims] 1. A method of manufacturing a shield structure in which a single metal plate is used, a top plate and a surrounding side plate are bent by press working, and a supporting tongue of a printed circuit board is provided on the side plate so as to protrude inward. A method for manufacturing a shield structure, characterized in that a protrusion that bulges outwardly is provided on the upper side of the position where the tongue of the plate is made, and the metal plate is bent into a top plate and a side plate at the position where the protrusion is provided.