JPH0565080B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a shield case,
In particular, it has a structure in which the space formed inside the outer frame is divided by a plurality of shield walls, and is integrally formed by bending a single molded metal plate. It is related to the shield case.

[Prior Art] A shield case is used in high frequency equipment such as an electronic tuner. For example, in the case of an electronic tuner, various circuits are configured on a circuit board incorporated into the outer frame of the shield case. Since these circuits need to be shielded from each other, shield walls must be appropriately provided in the shield case so as to divide the space surrounded by the outer frame. The number of such shield walls is particularly important when electronic tuners are used for UHF and VHF.
If circuits are provided for both, the number will increase further.

The shield case as described above is usually formed from a metal plate material. In this case, if the shield case is formed integrally by bending a single molded metal plate, the number of manufacturing steps will be reduced compared to when multiple metal plates are later assembled. , it is possible to provide a shield case at a lower cost, which is advantageous. However, it is not easy to form not only the outer frame but also the shield walls that divide the space surrounded by the outer frame from a single metal plate, especially when there are a large number of shield walls.

As a conventional example of a shield case that overcomes these difficulties and is integrally formed by bending a single molded metal plate, the one shown in Figs. 14 and 15 has been proposed. .

In this prior art, a shield case as shown in FIG. 15 is integrally formed by bending a molded metal plate as shown in FIG. 14.

This shield case is applied to an electronic tuner that includes both a UHF circuit section and a VHF circuit section. As shown in FIG. 15, this shield case includes an outer frame 5 consisting of first, second, third, and fourth side walls 1, 2, 3, and 4 that are successively connected. The space surrounded by the outer frame 5 is divided into two by a center shield wall 6 extending parallel to the second and fourth side walls 2 and 4. One of the two spaces divided by this center shield wall 6 becomes the UHF space 7 where the UHF circuit section is located, and the other is the UHF space 7 where the VHF circuit section is located.
This will be VHF space 8. UHF space 7 and
The VHF space 8 has a sub-shield wall 9,
10, 11 and sub-shield walls 12, 13, 1
4 into four spaces each, for example.

As shown in FIG. 14, the shield case as described above has a rectangular central region 15, and first, second, third, and fourth projecting regions projecting from each side of the central region 15, respectively. 16,1
It is formed by bending a metal plate having an external contour comprising 7, 18, 19. In FIG. 14, various bending lines are shown by dashed lines, and on each part that should become side walls 1 to 4 and shield walls 6, 9 to 14 when the shield case is constructed, , the corresponding reference number is shown in parentheses. As can be seen from the comparison between FIG. 14 and FIG. 15, the first, second, third, and fourth side walls 1, 2, 3, and 4 are
are formed from projecting regions 16, 17, 18, and 19, respectively. On the other hand, center shield wall 6, sub-shield walls 9, 10, 11, and sub-shield walls 12, 13, 14 are formed from central region 15, respectively.

[Problems to be Solved by the Invention] In the above-mentioned prior art, the shield walls 6, 9 to 14 that divide the space surrounded by the outer frame 5 of the shield case are all located in the central area 1 of the metal plate.
I'm trying to extract it from 5. However, the portions that should be used as the shield walls 6, 9 to 14 interfere with each other within a limited range of the central region 15, and it is also necessary to take into account the width dimension required for punching, so the shield walls 6, 9 to 14 , 9 to 14 cannot all be formed in a perfect state. Therefore, some sacrifice must be made in extracting each of the shield walls 6, 9-14 from the limited central area 15. This is the 16th
This is best shown in FIG.

FIG. 16 is a sectional view taken along the line - in FIG. 15, and FIG. 17 is a sectional view taken along the line - in FIG.
FIG. FIG. 16 clearly shows how the center shield wall 6 is formed. Further, FIG. 17 clearly shows how the sub-shield walls 10 and 13 are formed. Also,
16 and 17, a circuit board 2 for configuring various circuits included in the electronic tuner
0 is shown as an imaginary line. For example, regarding the center shield wall 6, relatively large defective portions 21 to 26 are formed on the circuit board 20, and regarding the sub-shield wall 10, a relatively large defective portion 27 is formed, and the sub-shield Regarding the wall 13, a relatively large defective area 28
is formed. Although not shown, defective portions are similarly formed in other sub-shield walls 9, 11, 12, and 14.

Due to the formation state of the shield walls 6, 9 to 14, various circuit sections configured on the circuit board 20 interact with each other in terms of high frequency.
This results in deterioration of tuning performance.

Therefore, the present invention aims to eliminate the defective parts that occur in each shield wall as described above while maintaining the economic advantages brought about by integrally forming the shield wall from a single metal plate. The purpose is to provide a structure for a shield case that can be almost completely eliminated.

[Means for Solving the Problems] The present invention is first directed to a shield case having the following structure. That is, a molded metal plate having an outer contour comprising a rectangular central region and first, second, third and fourth overhanging regions respectively extending from each side of the central region. An outer frame, which is formed integrally by bending the outer frame, and is made up of successive first, second, third, and fourth side walls, and the space surrounded by the outer frame is divided into two. a center shield wall extending parallel to the second and fourth side walls; and a space formed between the center shield wall and the second side wall. It's hot,
at least one first sub-shield wall extending parallel to the first and third side walls; dividing a space formed between the center shield wall and the fourth side wall; hand,
at least one second sub-shield wall extending parallel to the first and third side walls, and the first, second, third and fourth side walls are
In such a shield case, the center shield wall and the first sub-shield wall are respectively formed from the central region. Directed.

In this invention, in order to solve the above-mentioned technical problem, the second sub-shield wall is formed from a part of the fourth overhang area and a part of the central area following this. That is.

[Operation] According to the above-described characteristic configuration of the present invention,
The material to become the second subshield wall is taken not only from the central region but also from the fourth overhanging region. Therefore, the area of the metal plate material consumed by the second sub-shield wall in the central region is reduced, and the material required for the center shield wall and the first sub-shield wall can be taken out from the central region with a margin accordingly. I can do it.

[Effects of the Invention] According to the present invention, when taking out the walls necessary for the shield case from one metal plate, priority is given to taking out the center shield wall and the first and second sub-shield walls. Necessary dimensions can be ensured for each of these shield walls. Therefore, since each shield wall can be formed on the circuit board with almost no defects or voids, it is possible to reduce the high-frequency influence between the various circuit parts configured on the circuit board. , a shield case with high shielding performance can be obtained.

Note that a part of the fourth overhang area is consumed to form the second sub-shield wall, and therefore, the fourth side wall of the side walls constituting the outer frame has the second As a result of the formation of the sub-shield wall, a notch will occur. However, the occurrence of such a notch in the fourth side wall can be easily compensated for. For example, if this fourth side wall is used as a place to form a path for pulling out terminals from the inside of the shield case to the outside, if a terminal board holding such terminals is prepared separately, this The terminal plate makes it possible to compensate for a cutout in the fourth side wall. Moreover, regardless of whether a separately prepared terminal board is used or not, the fourth overhang area forming the fourth side wall is
Since the area is located at the end of one metal plate, it is easy to increase the degree of overhang. Therefore, in forming the fourth side wall, by bending the fourth overhanging region itself along a bending line parallel to the center shield wall, the portion where the metal plates overlap is folded. While forming
It is also possible to compensate for cuts in the fourth side wall.

[Example] Examples of the present invention will be described below with reference to FIGS.
Referring to FIG. 0, description will be made in relation to a shield case used in an electronic tuner. The shield case described here is substantially different from the conventional shield case in that the space surrounded by the outer frame is divided by various shield walls, as can be seen by comparing Fig. 2 with Fig. 15 described above. It is designed to be exactly the same.

First, a metal plate 30 as shown in FIG. 1 is prepared. Regarding the outer shape of the metal plate 30,
It is substantially the same as the conventional metal plate shown in FIG. That is, the metal plate 30 includes a rectangular central region 31 and first, second, third, and fourth projecting regions 32, 33, 34, and 35 projecting from each side of the central region 31, respectively.

On the other hand, by bending the molded metal plate 30 as shown in FIG. 1, a shield case 36 shown in FIG. 2 is integrally formed. The shield case 36 includes an outer frame 41 consisting of first, second, third, and fourth side walls 37, 38, 39, and 40 that are successively connected. The space surrounded by the outer frame 41 is divided into two by a center shield wall 42 extending parallel to the second and fourth side walls 38 and 40.
The space is divided into two parts, one of which is used as a UHF space 43 and the other as a VHF space 44. The UHF space 43 formed between the center shield wall 42 and the second side wall 38 is located between the first and third side walls 38.
It is further divided by first sub-shield walls 45, 46, 47 extending parallel to side walls 37, 39 of. On the other hand, the VHF space 44 formed between the center shield wall 42 and the fourth side wall 40 is
It is further divided by second sub-shield walls 48, 49, 50 extending parallel to the first and third side walls 37, 39.

In this embodiment, the first sub-shield walls 45 to
47 and the second sub-shield walls 48 to 50, but this number can be increased or decreased as desired;
for each subshield wall of at least one
All you need to do is prepare for each.

In order to obtain the shield case 36 shown in FIG. 2, bending is performed at various locations on the metal plate 30 shown in FIG. It is displayed on the board 30 with a dashed line. When bending in a predetermined direction is achieved through such a bending line, the second
The shield case 36 shown in the figure is obtained, and each wall 37 to
In order to clarify from which areas of the metal plate 30 the walls 40, 42, 45 to 50 are taken out, reference numbers representing these walls are written in parentheses in FIG. I'll attach it.

As shown in FIG. 1, the first, second, third and fourth side walls 37, 38, 39, 40 are
Second, third and fourth overhang areas 32, 33, 3
4 and 35, respectively. Further, the center shield wall 42 and the three first sub-shield walls 45, 46, and 47 are each formed from the central region 31. The feature of this invention is related to from which region of the metal plate 30 the portions to become the second sub-shield walls 48, 49, 50 are extracted. That is, these three second sub-shield walls 48, 49, and 50 are each formed from a part of the fourth overhang region 35 and a part of the central region 31 following this.

When bending the metal plate 30, the first
to fourth side walls 37 to 40, center shield wall 42 and three first sub-shield walls 45
- 47, if they are simply bent downward through the bending lines shown by the dashed-dotted lines in FIG.
A state as shown in FIG. 2 is obtained. Note that among such bending steps, in particular, the bending step of the center shield wall 42 can be performed without being interfered with by the second sub-shield walls 48-50. This is because the second sub-shield walls 48 to 50 remain connected to the fourth side wall 40 via a part of the metal plate 30, but the second sub-shield walls 48 to 50 remain connected to the center shield wall 42. This is because they are formed without being connected via the metal plate 30.

The second sub-shield walls 48 to 50 are arranged in any order with respect to the plane in which the fourth overhanging region 35 (fourth side wall 40) extends, but the
It is formed by carrying out the first folding step shown in the figure and the second folding step shown in FIGS. 6 and 7. Note that FIGS. 3 to 7 typically illustrate steps for bending the second sub-shield wall 48.

In the first folding step shown in FIGS. 3-5, subshield wall 48 is folded along fold line Y shown in FIG. The direction of the bending is chosen as indicated by arrows 51 and 52 in FIG. That is, the first
The left-hand side 53 in the figure will be located on the upper side after carrying out this first folding step. Note that FIG. 3 is a diagram showing the fourth side wall 40 from the same direction as FIG. 1, and when this is taken as a plan view, FIG. 4 is a right side view.
FIG. 5 is a front view.

Next, as shown in FIGS. 6 and 7, the second
A folding step is performed. In this second folding step, the folding is carried out along the folding line X shown in FIG.
The direction of arrow 54 shown in FIG. 7 is chosen. As a result, the side 53 of the sub-shield wall 48 is
The side wall 40 extends in a direction perpendicular to the extending plane. Note that FIG. 6 shows the fourth side wall 40.
This is a view shown from the same direction as FIG. 1, and FIG. 7 is a right side view when this is taken as a plan view.

When the second folding step described above has been completed and the folding along the fold line Z shown in FIG. and a third side wall 37,
Center shield wall 4 while lining up parallel to 39
2 and the fourth side wall 40 are connected.

Although not explained in detail, substantially the same bending step as that for the sub-shield wall 48 is performed on the other two second sub-shield walls 49 and 50, and the bending steps are as shown in FIG. state.

Such second sub-shield walls 48 to 50
is not particularly fixed to the center shield wall 42 by simply completing the bending.
However, such fixing can be easily achieved, for example by soldering. This soldering can be accomplished not only by dipping the bent shield case 36 into a solder bath as shown in FIG.
This can also be achieved simultaneously when the circuit board 55 shown in phantom lines in FIGS. 9 and 10 is soldered to the shield case 36 using a solder dip. That is, in the solder dip process, the solder is easily sucked up into the spaces between the sub-shield walls 48 to 50 and the center shield wall 42 by capillary action.

FIG. 8 mainly shows the fourth side wall 40 from the direction of the arrow along the line - in FIG. As can be seen from this drawing, the fourth side wall 4
0, a relatively large notch 56 is formed as a result of the formation of the second sub-shield walls 48-50.

9 is a cross-sectional view taken along the line - in FIG. 2, and FIG. 10 is a cross-sectional view taken similarly along the line -. These FIGS. 9 and 10 correspond to FIGS. 16 and 17 described above, respectively. As can be seen from these drawings, when the circuit board 55 shown by the imaginary line is assembled into the shield case 36, the center shield wall 42, the first sub-shield wall 46, the second sub-shield wall 49, and the circuit board There are no defective parts between it and 55. Other first sub-shield walls 45, 47 and second sub-shield walls 48, 5
The same applies to 0, although it is not shown. Therefore, the outer frame 4 is divided by the center shield wall 42 and the sub-shield walls 45 to 50.
1 are completely or almost completely shielded from each other, so that the various circuit parts configured on the circuit board 55 are advantageously prevented from influencing each other at high frequencies.

As clearly shown in FIG. 8 mentioned above, a relatively large notch 56 is formed in the fourth side wall 40. As shown in FIG. Although this is undesirable as it leads to a decrease in shielding performance, it can be easily solved with the structures shown in FIG. 11, FIG. 12, and FIG. 13, respectively, which will be described below.

The structure shown in FIG. 11 focuses on the fact that in an electronic tuner or the like equipped with this type of shield case 36, a path for drawing out the terminal from the inside of the shield case 36 to the outside must be formed somewhere. The purpose is to use the notch 56 formed in the fourth side wall 40 as a path for pulling out such a terminal.
That is, a terminal plate 59 is prepared in which a plurality of terminal pins 57 are each held via a cylindrical feedthrough capacitor 58. This terminal plate 59 is attached to the shield case 36 along the fourth side wall 40. As a result, the terminal plate 59 acts to close the notch 56 of the fourth side wall 40, and the notch 56 can be used as it is as a path for penetrating the plurality of terminal pins 57. can.

In addition, in the structure shown in FIG. 11, if the terminal corresponding to the terminal pin 57 is pulled out from another location of the shield case 36, a simple flat plate may be used instead of the terminal plate 59. . This plate itself may be composed of a metal plate, or may be composed of a plate made of an insulating material with a metal film formed on one side.

12 and 13 show another example for closing the notch 56 formed in the fourth side wall 40 shown in FIG. 8. Note that FIG. 12 is a diagram corresponding to FIG. 1, but the metal plate 30a
Only a portion of it is shown. Figure 13 shows the first
12 is a sectional view taken along the line - in FIG. 12, showing a part of a shield case 36a formed by bending the metal plate 30a shown in FIG. 2, and corresponds to FIG. 10.

As shown in FIG. 12, the fourth overhanging area 35a formed on the metal plate 30a is similar to the first, second and third overhanging areas 32, 33, 34 (equivalent area 33).
are not shown in FIG. ) is formed to protrude more than the other. This is the fourth
Since the overhanging region 35a is located at the end of the metal plate 30a, this can be easily realized. This fourth overhang region 35a is itself bent through a bend line 60 parallel to the center shield wall 42 (FIG. 1). In order to facilitate such bending, a plurality of discontinuously extending slits 61 may be formed along the bending line 60. Compared to the embodiment described above with reference to FIGS. 1 to 10, this embodiment only increases the number of folding steps via the folding line 60, and the other folding steps are teeth,
Since they are similar, the explanation will be omitted. In this way, the fourth overhanging region 35a is inserted through the bending line 60.
When itself is bent, the fourth side wall 40a
As shown in FIG. 13, the metal plate has a double overlapping portion.

Note that, as shown in FIG. 12, a plurality of through holes 62 may be formed in a portion of the fourth overhang region 35a closer to the edge than the bending line 60. This through hole 62 is used, for example, to mount the feedthrough capacitor 58 that holds the terminal pin 57 shown in FIG. 11.

However, if a path for drawing out the terminal from the inside of the shield case 36a to the outside is formed at another location, it is not necessary to provide the through hole 62 as described above.

Although this invention has been described above with reference to several illustrated embodiments, still other embodiments are possible within the scope of this invention.

For example, as shown in FIGS. 9 and 10, in this embodiment, on the lower side of the circuit board 55, each of the shield walls 42, 45-50 forms a relatively large defective portion. This is because, on the lower side of the circuit board 55, the lack of shielding between the various circuit sections configured on the circuit board 55 does not pose much of a problem. However, if necessary, the shield walls 42 and 45 on the lower side of the circuit board 55 may be installed to improve shielding performance also on the lower side of the circuit board 55.
It is easy to change the shape of ~50.

Further, the shield case according to the present invention is premised on being integrally formed by bending one molded metal plate, and four side walls are formed from such one metal plate. an outer frame comprising an outer frame, a center shield wall, at least one first sub-shield wall and at least one second
The requirement is to take out the sub-shield wall of the metal plate, but it also falls within the scope of this invention if elements other than the above-mentioned outer frame and various shield walls are taken out within the scope of this one metal plate. It is something. Also, in the completed shield case,
It is also within the scope of the present invention that parts other than those integrally formed from one metal plate are later attached as separate parts.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a metal plate 30 for obtaining a shield case according to an embodiment of the present invention.
FIG. 2 is a top view of a shield case 36 formed using the metal plate 30 of FIG. 3 to 5 show the first part of the second sub-shield wall 48.
FIG. 3 is a plan view, and FIG.
The figure is a right side view, and FIG. 5 is a front view. 6 and 7 show the fourth part of the second sub-shield wall 48.
FIG. 6 is a plan view, and FIG.
The figure is a right side view. Figure 8 shows the line -
FIG. 4 is a view mainly showing the fourth side wall 40 from the direction of the arrow along. Figure 9 shows the line -
FIG. FIG. 10 is a sectional view taken along the line - in FIG. 2. FIG. 11 is a top view for explaining another embodiment of the present invention, showing a state in which a terminal plate 59 is attached along the fourth side wall 40. FIG. 12 is a diagram for explaining still another embodiment of the present invention, in which a metal plate 30 used for forming a shield case is shown.
It is a top view showing a part of a. Figure 13 shows the first
This figure shows a part of the shield case 36a obtained using the metal plate 30a shown in FIG. 2, and shows a cross section corresponding to the cross section taken along the line - in FIG. 12. FIG. 14 is a plan view showing a metal plate used to obtain a conventional shield case. FIG. 15 is a top view showing a shield case formed using the metal plate shown in FIG. 14. 1st
FIG. 6 is a sectional view taken along the line - in FIG. 15. FIG. 17 is a sectional view taken along the line - in FIG. 15. In the figure, 30 and 30a are metal plates, 31 is a central area, 32 is a first overhang area, 33 is a second overhang area, 34 is a third overhang area, and 35 and 35a are fourth overhang areas. an exit area, 36, 36a a shield case, 37 a first side wall, 38 a second side wall,
39 is a third side wall, 40, 40a are fourth side walls, 41 is an outer frame, 42 is a center shield wall, 45, 46, 47 are first sub-shield walls,
48, 49, 50 are second sub-shield walls, 56
is a notch, 57 is a terminal pin, 62 is a through hole,
Y, 60 is a bending line.

Claims (1)

[Scope of Claims] 1. Having an outer contour including a rectangular central region and first, second, third, and fourth overhanging regions extending from each side of the central region, respectively;
an outer frame that is integrally formed by bending a single molded metal plate and that is made up of sequentially connected first, second, third, and fourth side walls; A center shield wall that divides the space surrounded by the frame into two and extends parallel to the second and fourth side walls; and between the center shield wall and the second side wall. It is something that divides the space that is formed,
at least one first sub-shield wall extending parallel to the first and third side walls; dividing a space formed between the center shield wall and the fourth side wall; hand,
at least one second sub-shield wall extending parallel to the first and third side walls, and the first, second, third and fourth side walls are
In the shield case, wherein the first, second, third, and fourth overhang regions are respectively formed, and the center shield wall and the first sub-shield wall are each formed from the central region, 2. The shield case, wherein the second sub-shield wall is formed from a part of the fourth overhang area and a part of the central area following the fourth overhang area. 2. The second sub-shield wall remains connected to the fourth side wall through a part of the metal plate, while the second sub-shield wall remains connected to the center shield wall through a part of the metal plate. The shield case according to claim 1, which is formed without being connected via. 3. The shield case according to claim 1 or 2, wherein the fourth side wall forms a path for drawing out the terminal from the inside of the shield case to the outside. 4. The fourth overhang area is larger than the first, second and third overhang areas,
The fourth side wall is formed by bending the fourth overhang region itself along a bending line parallel to the center shield wall, and includes a double overlapping portion of the metal plate. A shield case according to any one of claims 1 to 3.