JPH0143914Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is applicable to a frame-shaped base for shielding in high-frequency electric equipment, a frame-shaped shield partition plate that partially shields a printed wiring body built into the base, etc. Regarding a metal frame structure.

Conventional Technology High-frequency electrical equipment such as electronic tuners for TVs and VTRs generally has a structure in which a printed circuit board, in which high-frequency circuit components are embedded and wired, is housed in a shield case to prevent unnecessary radiation. The shield case has a structure in which a shield cover is fitted to the upper and lower openings of a frame-shaped base made by punching and bending a metal plate.The frame-shaped base has three parts of one band-shaped metal plate placed on the same side depending on the application. There are those that are formed into a frame shape that is bent at 90 degrees, and those that are formed into a frame shape that are made of four roughly rectangular metal plates that are integrally molded in a rectangular arrangement on the same plane. A conventional example of the latter frame-shaped base will be described below with reference to FIGS. 5 to 9.

The frame-shaped base 1 in FIG. 5 has a total of four side plates 2a to 2d arranged on the same plane in a rectangular arrangement as shown in the developed view in FIG. Formed at the inner corner portion, each side plate portion 2a~
A total of four joint parts 3a~ that integrate 2d in a series
It is formed by bending each side plate 2a to 2d of the metal plate 4 made of 3d by 90 degrees toward the same side from the joint portions 3a to 3d. Each side plate portion 2a to 2d is bent at a joint portion 3.
This is also done at the boundary between a to 3d. For example, two side plate parts 2 connected by one joint part 3a
As shown in FIG. 6, steps 5a and 5b are formed on the corresponding end faces of a and 2b, and the steps 5a and 5b fit into each other at a depth equal to the plate thickness, and the steps 5a and 5b are formed by bending both side plate portions 2a and 2b.
The two side plate portions 2a and 2b are meshed together to ensure a secure connection between the side plate portions 2a and 2b, thereby improving the shielding properties of the joint portion.

Note that the two opposing side plates 2 of the frame-shaped base 1
b, 2d have extensions 6, 6 formed on one end thereof that protrude from the side plate 2c, and mounting pieces 7, 7 are formed by bending the lower sides of these extensions 6, 6 inward at 90 degrees. .
The mounting pieces 7, 7 are used as means for screwing the base 1 to an external device.

Further, the side plate portions 2a to 2d of the metal plate 4
As shown in FIGS. 8 and 9, the joint parts 3a to 3d are clamped and fixed between the upper and lower molds 8, 8', and then the sides of the upper and lower molds 8, 8' are bent. On the other hand, the side plate portions 2a to 2d are pressed and bent using a bending die 10 that moves up and down at intervals equal to the thickness of the metal plate 4.

Problems to be solved by the invention By the way, the bending of the side plate parts 2a to 2d is performed at the boundary with the joint parts 3a to 3d. It is difficult to do this with high precision, so after bending each side plate part 2a~
2d, and in the example shown in FIG. 6, the steps 5a and 5b of the side plate portions 2a and 2b did not match, resulting in a large gap between them.
In addition, the bending process requires a greater force as the thickness of the metal plate 4 increases, resulting in a problem that the life of the mold used for the bending process is shortened. Furthermore, the joint part 3a
The length of the boundary between side plate portions 2a to 2d of ~3d is 4 times the plate thickness in order to obtain the necessary bending accuracy and mechanical strength.
5 times or more, and even if the plate thickness is 0.5 mm or less, a thickness of 2 to 3 mm or more is required, making it difficult to reduce the area of the joints 3a to 3d. Therefore, as the base 1 becomes smaller due to the recent miniaturization of electronic tuners, etc., the ratio of the area occupied by the joint parts 3a to 3d to the base 1 increases. The parts 3a to 3d often become noticeable and get in the way, and in order to deal with this, it is necessary to leave the parts corresponding to the joint parts 3a to 3d of the printed wiring body and install it into the base 1, and then attach the electronic parts. It has been necessary to take measures such as processing or bending the electronic components to be attached to the joint portions 3a to 3d of the printed wiring body into unreasonable shapes.

Means for Solving the Problems The technical problem of the present invention is to solve the following problems: Each side plate of a metal plate is formed by connecting a plurality of substantially rectangular side plate portions that are continuously arranged substantially perpendicularly on the same plane to each other at a joint portion. By bending the side plate part of a metal frame formed into a frame shape by bending the metal frame from the boundary part with the joint part, the side plate part can be easily and accurately bent, and the area of the joint part can be reduced. be.

The technical means of the present invention to solve this technical problem is to previously form a groove in the bent portion that is the boundary between the joint portion and the side plate portion in a direction along the bent portion.

Effect: According to this technical means, the part of the joint before bending that is scheduled to be bent has a structure that is easy to bend due to the formation of grooves, so even if the plate thickness of the joint is large, the bending of the side plate is not possible. This also improves bending accuracy. In addition, the ease of bending and high precision make it possible to reduce the area of the joint.

Example The present invention is applied to a metal frame (frame-shaped base) similar to that shown in Fig. 5, and an example thereof is shown in Figs.
This will be explained below with reference to the figures.

In FIG. 1, the same parts as in FIG. 5 are given the same reference numerals, and their explanation will be omitted. The difference is the joint parts 10a to 10 that connect the side plate parts 2a to 2d.
d, its feature is that the length of each side of the joint part is 1 mm and 1.5 mm, respectively, which are two to three times the thickness of the plate used, which is 0.5 mm. and joint parts 10a to 10d
For example, grooves 11 and 1 are formed on the outer surface of the bent portion that is the connection portion with the side plate portions 2a to 2d in the direction along the bent portion.
1,... are formed in advance. This groove 11,
11, . . . are formed by using a tool such as a notch on a metal plate 4' which has been punched out and is not yet bent, as shown in FIGS. 2 and 3. Also grooves 11,1
1, . . . are formed with a V-shaped or U-shaped cross section.

The grooved metal plate 4' is bent in the same manner as before, for example, as shown in FIG.
This is done by clamping and fixing the joint parts 10a to 10d at 8' and pressing and bending the side plate parts 2a to 2d with a bending die 9. The bending at this time is from the joint portion 10a to
The force required for this occasional bending is enough to bend the thickness of the joints 10a to 10d minus the depth of the grooves 11, 11,... Therefore, bending can be performed easily with less force, resulting in less damage to the mold and longer life, as well as higher precision bending.
In addition, due to the ease of bending and high precision, the area of the joint parts 10a to 10d only needs to be for mechanical strength, and the area is smaller than that of conventional products.
The degree of freedom in designing the shape increases.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, the grooves 11, 11, . Further, the present invention is not limited to frame-shaped bases, but can be similarly applied to frame-shaped shield partition plates and the like.

Effects of the Invention According to the present invention, even if the thickness of the metal plate is large, the bending of the side plate portion is easy, the bending dimension is accurate, and a metal frame structure with good assembly accuracy can be provided. In addition, the area of the joints that connect the side panels can be reduced by improving the bending accuracy, making it convenient for the placement and design of printed wiring bodies, etc. that are incorporated into the metal frame, and creating a metal frame structure with great practical value. can be provided.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention;
The figure is a developed view of the metal frame structure in Figure 1, Figure 3 is an enlarged sectional view taken along line A-A in Figure 2, and Figure 4 is a partial enlargement of the device for bending the metal frame in Figure 1. FIG. Fig. 5 is a perspective view showing an example of a conventional metal frame, Fig. 6 is a partially enlarged perspective view of Fig. 5, Fig. 7 is a developed view of the metal frame of Fig. 5, and Figs. 8 and 9. 5 are partial cross-sectional views of the apparatus for bending the metal frame of FIG. 5 in various states; FIG. 2a to 2d...Side plate part, 4'...Metal plate, 10
a to 10d... joint part, 11, 11,...,...
groove.

Claims (1)

[Scope of utility model registration request] Consisting of approximately rectangular side plate parts that are arranged continuously and substantially perpendicular to each other, and a joint part that connects the adjacent side plate parts together, from the boundary between each side plate part and the joint part to the same side. In a metal plate that is bent and formed into a frame shape, a groove is formed in advance in the bent part of the joint part in a direction along the bent part so that at least one side of the joint part is not more than three times the thickness of the plate. A metal frame structure characterized by: