JPH03283500A - Manufacture of noise shied board - Google Patents

Abstract

PURPOSE:To enable a molded body to be easily released from a die and a die to be hardly damaged by a method wherein magnetic substance powder is filled into a top force which forms the upper part of a shield board, a core composed of a protrusion, a curved surface part extending from the top of a base to the protrusion, and the base, and a bottom force and compressed. CONSTITUTION:A top force 2 which forms the upper part of an shield board, a bottom force 3 which forms the lower part of the shield board, and a core 7 composed of a base 4 inserted into the bottom force, a protrusion 5 which forms a insertion hole, and a curved surface part 6 extending from the top of the base 4 to the prescribed point on the outer circumferential face of the protrusion are provided. The distance t between the top of the base 4 and the upside of the bottom force 3 is set minimal taking the dispersion of ferrite material powder in lots into consideration. A cavity formed by the top force 2, the core 7, and the bottom force 3 is filled with magnetic material powder and compressed to form a molded body, and the molded body is sintered into a noise shield board.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a method for manufacturing a noise shielding plate that shields noise from or to electronic components used in electronic equipment. .

(Prior Art) As a conventional noise shielding plate, those shown in FIGS. 4 and 5 are known. FIG. 4 is a plan view of a conventional noise shielding plate, and FIG. 5 is a partially enlarged sectional view taken along the line A--A in FIG. 4.

The noise shielding plate 31 shown in the figure is made of ferrite raw material powder (
The film is made of a ferrite substrate 33 formed by molding a required number of through holes 32 through which terminals of electronic components are inserted by pressing a magnetic powder) and then sintering the film.

Further, as shown in FIG. 5, the diameter d1 of the opening lower end 32a, which is the terminal insertion side of the electronic component, of the insertion hole 32 is a reference diameter d.
. A curved surface portion 32c having a larger diameter and a curved surface shape upward from the opening lower end portion 32a side is formed, and a cylindrical shape having the same shape is formed from the terminal end of the curved surface portion 32c to the opening upper end portion 32b.

When manufacturing the noise shielding plate 31 having the above configuration using a mold, as shown in FIG. A molded body is obtained by filling a space region formed by a lower die 35 having a protruding portion 36 and a curved surface portion 37 with ferrite raw material powder and compressing it.

However, when such a mold as described above is used, a problem arises in that the molded body obtained by compression molding often becomes unable to be removed from the mold.

In order to solve this problem, as shown in FIG. 7, there is a structure in which the protruding part 36 is made into a separate body and has a medium size. A new problem arises in that the thin portion 37a is damaged. As an improvement to this, when a mold having a structure in which the thin wall portion 37a is reinforced and a thick wall portion 37b is used as shown in FIG. 8, a molded body (after sintering, the ferrite The opening lower end 32 of the substrate 33)
A flat portion 32d parallel to the lower surface of the molded body is formed on the a side, causing a problem in that the terminal comes into contact with the flat portion 32d, making insertion work difficult.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned problems, and provides a noise shielding plate in which the molded body can be easily taken out and a mold that is hard to break is used to facilitate the insertion of terminals. The purpose is to provide a manufacturing method that can manufacture.

[Structure of the Invention] (Means for Solving the Problems) The structure of the present invention is a method for manufacturing a noise shielding plate formed in a plate shape of a magnetic material and having an insertion hole through which a terminal of an electronic component is inserted. an upper mold forming an upper surface part of the shielding plate;
It has a lower mold forming a lower surface part, a base inserted into the lower mold, and a protrusion forming the insertion hole, and extends from the tip of the base to a predetermined position on the outer peripheral surface of the protrusion. and a middle mold having a curved surface portion formed in a curved shape, and a molded body is obtained by filling the spatial region formed by the upper mold, the middle mold, and the lower mold with magnetic powder and compressing it. It is something to do.

(Function) Since a molded body is obtained by filling and compressing the magnetic powder with the upper mold, middle mold, and lower mold having the above configuration, the molded body can be easily taken out, and the middle mold having the above configuration is used. Therefore, it is possible to manufacture a noise shielding plate in which the mold is less likely to be damaged and the terminal can be easily inserted.

(Example) An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a noise shielding plate manufactured by a manufacturing method according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of a portion taken along line B-B in FIG. 1, and FIG. 3 is a manufacturing method according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a mold for explaining the method.

First, the structure of the noise shielding plate will be explained with reference to FIGS. 1 and 2.

The noise shielding plate 11 shown in the figure is made of ferrite raw material powder (
The film is composed of a ferrite substrate (plate-shaped body) 13 formed by molding a required number of insertion holes 12 through which terminals of electronic components are inserted by pressing or the like (magnetic powder) and then sintering the film.

Further, as shown in FIG. 2, the diameter d3 of the opening lower end 12a of the insertion hole 12, which is the terminal insertion side of the electronic component, is a reference diameter (
In this embodiment, the diameter is the same as the diameter of the opening upper end portion 12b) and is larger than the diameter of the opening upper end portion 12b.

On the opening lower end 12a side, there is a straight part 12c (same diameter as d3) that is perpendicular to the lower surface of the ferrite substrate 13 toward the opening upper end 12b side (upward);
Curved surface part 1 having a curved surface extending from the terminal end of c to a predetermined position
2d, and a reference diameter d extending from the terminal end of the curved surface portion 12d to the opening upper end portion 12b. It is formed into a cylindrical shape.

Next, with reference also to FIG. 3, the structure of the mold used in the manufacturing method of one embodiment of the present invention and the manufacturing method of the noise shielding plate will be described.

The mold 1 shown in FIG. 3 includes an upper mold 2 forming the upper surface part of the shielding plate 11, a lower mold 3 forming the lower surface part, and this lower mold 3.
The base 4 inserted into the base 4 and the protrusion 5 forming the insertion hole 12
and a medium mold 7 having a curved surface 6 formed in a curved shape extending from the tip of the base 4 to a predetermined position on the outer peripheral surface of the protrusion 5. Further, it is preferable that the distance t from the tip of the base 4 of the medium mold 7 to the upper surface of the lower mold 3 be set to a minimum, taking into account variations between lots of ferrite raw powder (magnetic powder), etc. .

Then, the upper mold 2. Medium size 7. The spatial region formed by the lower die 3 is filled with magnetic powder and compressed to obtain a molded body, and then this molded body is sintered to manufacture the noise shielding plate 11.

Upper mold having the structure as described above 2. Medium size 7. According to the manufacturing method using the lower mold 3, the compression-molded molded body can be easily taken out, and since the middle mold 3 having the above structure is used, the mold is less likely to be damaged, and the noise produced by sintering this molded body can be reduced. According to the shielding plate 11, the curved surface portion 12d facilitates the insertion work of the terminal.

The present invention is not limited to the above-mentioned embodiments, but can be implemented in various modifications.

For example, the magnetic material is not limited to ferrite, but may be any other magnetic material, and the shape of the noise shielding plate can be modified in various ways.

[Effects of the Invention] As detailed above, the present invention provides a manufacturing method for manufacturing a noise shielding plate in which the molded body can be easily taken out and the terminal can be easily inserted using a mold that is difficult to break. can be provided.

[Brief explanation of drawings]

FIG. 1 is a plan view of a noise shielding plate manufactured by a manufacturing method according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of a portion taken along line B-B in FIG. 1, and FIG. 3 is a manufacturing method according to an embodiment of the present invention. A schematic sectional view of a mold for explaining the method, FIG. 4 is a plan view of a conventional noise shielding plate, FIG. 5 is a partial enlarged sectional view taken along line A-A in FIG. 4, and FIG. 6 is a diagram of conventional manufacturing. FIG. 7 is a schematic cross-sectional view of a mold for explaining the conventional manufacturing method. FIG. 8 is a schematic cross-sectional view showing an improved example of the mold for explaining the conventional manufacturing method. FIG. 9 is a schematic cross-sectional view showing another improved example of the mold. FIG. 9 is a partially enlarged cross-sectional view of a noise shielding plate manufactured using the mold shown in FIG. ...Mold, 2...Upper mold, 3...Lower mold,...
Base, 5...Protrusion, 6...Curved surface part,...Medium size,
11... Noise shielding plate, 2... Insertion hole, 12a
... Lower end of the opening, 2b... Upper end of the opening, 13...
・Ferrite substrate. ＼ 2 2 Figure 9

Claims (1)

[Claims] In a method for manufacturing a noise shielding plate formed into a plate-like body made of a magnetic material and having an insertion hole through which a terminal of an electronic component is inserted,
The shielding plate has an upper mold that forms the upper surface part, a lower mold that forms the lower surface part, a base inserted into the lower mold, and a protrusion that forms the insertion hole, and from the tip of the base. a middle mold having a curved surface portion formed in a curved shape over a predetermined position on the outer peripheral surface of the protrusion, the upper mold, the middle mold,
A method for manufacturing a noise shielding plate, which comprises filling a spatial region formed by a lower die with magnetic powder and compressing it to obtain a molded body.