JPH0983162A - Control rack structure for electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a control rack structure which prevents the leak of radio waves at a frequency in a regulated range even when a printed-circuit board having a large height is housed and which houses the printed-circuit board easily. SOLUTION: In a control rack structure for an electronic apparatus, a plurality of printed-circuit boards 2 are housed at intervals in nearly parallel at the inside of a box-shaped rack body 1 which is grounded electrically. The control rack structure is provided with a conductive sealed beam 3 which is slender and which is formed to be longer than a part between side plates 13 at the rack body 1 situated on both face sides of the printed-circuit boards 2. The sealed beam 3 is attached to the rack body 1 at least on one out of an opening 15 at the rack body 1 and the inside of a back plate 14 facing the opening 15 at the rack body 1 in a state that it crosses all the printed-circuit boards 2 housed inside the rack body 1 and that it is brought in to contact with all the printed-circuit boards 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control rack structure for electronic equipment having a plurality of printed circuit boards housed therein.

[0002]

2. Description of the Related Art As a conventional control rack structure for electronic equipment of this type, there is a subrack structure disclosed in JP-A-6-6057. In this subrack structure, a plurality of printed circuit boards are accommodated in a subrack body having a box-like shape and an opening at the front, substantially in parallel with the side plates of the subrack body, at a predetermined pitch, and accommodated prints. A conductive shield plate is provided along the end of the circuit board on the opening side. A contact spring electrically connected to the subrack main body is provided on one or both of the upper end and the lower end of the subrack main body along the upper end and the lower end. The circuit board is housed in the subrack body with the upper side and the lower side of the shield plate in contact with the contact springs.

In the above subrack structure, the subrack main body is electrically grounded by being attached to an electronic device, and the printed circuit board is electrically grounded via the contact spring. Therefore, since the radio waves emitted by the printed circuit board move from the upper end side and the lower end side to the subrack body via the shield plate and the contact spring, it is possible that the printed circuit board is shielded against the electric wave. Therefore, it is possible to prevent malfunction of the housed printed circuit board due to electromagnetic interference (EMI) and damage to the internal circuit due to electrostatic breakdown (ESD).

By the way, the regulations of the Voluntary Control Council for Radio Interference (VCCI) in electronic equipment such as information processing equipment are applied to radiated radio waves of 30 MHz to 1 GHz. Radio waves that fall within the range of this frequency are subject to restrictions on their strength.

[0005]

However, in the above-described conventional subrack structure, when the dimension between the upper end portion and the lower end portion of the printed circuit board, that is, the height dimension is large, the opening side of the subrack main body and this opening are formed. From the gap formed between the printed circuit boards adjacent to each other on the side opposite to
There is a drawback that radio waves in a frequency range regulated by CCI are likely to leak.

That is, for example, the wavelength (λ) of a radio wave having a frequency of 1 GHz is calculated as follows: λ = light speed / frequency = 300,000 Km / 1 GHz = 30 cm, which is 1/2 of the radio wave having a frequency of 1 GHz. The wavelength is
It is calculated to be about 15 cm. Therefore, if there is a gap of 15 cm or more, radio waves with a frequency lower than 1 GHz and regulated by VCCI may leak from the gap. In the above subrack structure, the gap between adjacent printed circuit boards is not interrupted at all in the length direction thereof, and the height dimension of the printed circuit board becomes the length of the above described gap. If the height dimension is large, radio waves with frequencies in the range regulated by VCCI are likely to leak.

In order to prevent the above-mentioned radio wave leakage, a contact spring similar to that attached to the upper end portion and the lower end portion should be provided between the upper end and the lower end of the opening of the subrack body. Then, since the contact spring must be installed in the opening in advance, when the printed circuit board is housed in the subrack body, the electronic components mounted on the surface of the printed circuit board hit the contact spring, making it difficult to house. become. Therefore, even if a printed circuit board having a large height is accommodated, it is expected to develop a rack structure capable of preventing the leakage of radio waves having a frequency within the regulation range and easily accommodating the printed circuit board.

[0008]

SUMMARY OF THE INVENTION The present invention is a control for an electronic device in which a plurality of printed circuit boards are housed in parallel in a box-shaped rack body which is electrically grounded. It was done in a rack structure. That is,
According to the present invention, there is provided a conductive shield beam which is elongated and is formed longer than both inner surfaces of the rack main body located on both sides of the printed circuit board. At least one of the opening of the main body and the inner surface on the side facing the opening of the rack main body,
The printed circuit board accommodated in the rack main body is attached to the rack main body in a state of traversing all of the printed circuit boards and in contact with all of the printed circuit boards, which is a means for solving the above problems.

According to the present invention, the following effects can be obtained. In such a control rack structure, the conductive shield beam is attached to the rack body in a state of being in contact with all of the printed circuit boards housed in the rack body. The rack body is electrically connected. Therefore, when the rack body is electrically grounded, the printed circuit board and the shield beam are also electrically grounded, so that the radio waves emitted by the printed circuit board are emitted to the shield beam,
The printed circuit board is shielded against radio waves. Further, since the shield beam is arranged so as to traverse all the printed circuit boards housed in the rack body, the shield beam is arranged so that the shield beam is arranged in the opening of the rack body and the inner surface on the side opposite to the opening of the rack body. On at least one side, a gap formed between adjacent printed circuit boards is divided by a shield beam in the length direction,
The length of each divided gap becomes shorter. Also, since the elongated shield beam is attached so as to cross the printed circuit board housed in the rack body, when the shield beam is arranged in the opening of the rack body,
Since the shield beam is attached after the printed circuit board is housed in the rack body, the shield beam does not hinder the printed circuit board when housed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a control rack structure for electronic equipment according to the present invention will be described in detail below. FIG. 1 is a diagram for explaining an embodiment of the present invention, (a)
Is a front view, (b) is a sectional view taken along the line AA in (a), and (c) is a sectional view taken along the line BB in (a). As shown in FIG. 1, the control rack structure includes a rack body 1, a plurality of printed circuit boards 2 housed inside the rack body 1, and a shield beam 3 attached to the rack body 1.

The rack body 1 is made of a conductive material, and is fixed to an electronic device (not shown) so that it can be electrically grounded at the same time. For example, it is formed in a box shape with a front opening 15 in which a pair of side plates 13 is arranged between the top plate 11 and the base plate 12 and a back plate 14 is provided in the rear. A plurality of printed circuit boards 2 are accommodated in the rack body 1 at a predetermined interval and substantially in parallel to the side plates 13, and the inner surface of the back plate 14 inside the rack body 1 ( Hereinafter, internal connectors (not shown) are arranged at the same pitch as the accommodation pitch of the printed circuit board 2 on the inner surface).

The printed circuit board 2 has a substantially rectangular shape, and the upper end portion 21 and the lower end portion 22 of the rack body 1 on the side of the opening 15 are in contact with and fixed to the end surfaces of the top plate 11 and the base plate 12 on the side of the opening 15 respectively. It is housed in the rack body 1 while being fixed by the screws 4. That is, the printed circuit board 2
The dimension (hereinafter referred to as the height dimension) from the upper end 21 to the lower end 22 excluding the opening 15 side is formed slightly smaller than the dimension from the inner surface of the top plate 11 to the inner surface of the main plate 12. The height dimension of the printed circuit board 2 on the opening 15 side is larger than this dimension, for example, substantially equal to the dimension from the outer surface of the top plate 11 to the outer surface of the base plate 12.

The end surface 23 of the printed circuit board 2 on the side of the opening 15 is formed such that the dimension in the direction substantially orthogonal to the height direction (hereinafter referred to as the width dimension) is substantially equal to the accommodation pitch of the printed circuit board 2. Has been done. Further, the printed circuit board 2 is provided with a connector 24 which is connected to an internal connector of the rack body 1 at the end portion on the back plate 14 side.

On the other hand, as shown in the perspective view of FIG. 2, the shield beam 3 has a metallic main body 31 which is elongated and has, for example, a substantially rectangular cross section, and a longitudinal direction on one surface of the main body 31. And a conductive sponge 32 that is provided electrically continuously. The main body 31 is formed longer than the inner surface of the pair of side plates 13 located on both sides of the printed circuit board 2, and is, for example, substantially equal to or slightly longer than the outer surface of the pair of side plates 13. Has been formed. Further, the conductive portions 32 are provided at both ends in the length direction.
An L-shaped attachment side 33 is provided so as to extend outward from the surface. Then, in the attachment side 33, a screw hole 34 for fixing through which a screw is inserted when fixing the shield beam 3 to the rack body 1 is formed on a surface substantially parallel to the surface of the conductive portion 32.

Here, one shield beam 3 having such a structure is attached at the opening 15 of the rack body 1 and at a substantially intermediate height position of the printed circuit board 2.
At this time, the shield beam 3 is arranged so as to traverse the printed circuit board 2 housed in the rack body 1 and the conductive sponge 32 is in contact with the end surface 23 of the printed circuit board 2 on the opening 15 side. , Is fixed by being screwed to a mounting side (not shown) of the rack body 1.

In such a control rack structure, the upper end portion 21 and the lower end portion 22 of the printed circuit board 2 are housed in the rack body 1 while being in contact with the end faces of the top plate 11 and the bottom plate 12 of the rack body 1, respectively. Printed circuit board 2
And the rack body 1 are electrically connected. Further, the shield beam 3 is provided at a height position approximately in the middle of the printed circuit board 2.
However, the printed circuit board 2 and the rack body 1 are electrically connected to each other via the shield beam 3 because they are fixed to the rack body 1 while being in contact with all of the accommodated printed circuit boards 2. Therefore, when the rack body 1 is attached to an electronic device (not shown) and electrically grounded, the printed circuit board 2 and the shield beam 3 can also be electrically grounded, and the radio waves emitted by the printed circuit board 2 can be emitted to the ground side.
The printed circuit board 2 can be electromagnetically shielded.

Further, in this control rack structure, since the shield beam 3 is arranged at a height position approximately in the middle of the printed circuit board 2, a gap 25 formed between the printed circuit boards 2 adjacent to each other in the opening 15 is formed. Can be divided into about half, and as a result, the length of each gap 25 can be shortened. Therefore, even if the height of the printed circuit board 2 is large, the length of the gap 25 is set to V
It can be made shorter than the dimension where radio waves in the frequency range regulated by CCI may leak to the outside. Moreover, as described above, the shield beam 3 that divides the gap 25 is electrically grounded, so that the radio waves emitted by the printed circuit board 2 can be emitted to the ground side. Therefore, the control rack structure of this embodiment can reliably prevent malfunction of the housed printed circuit board 2 due to EMI and damage to the internal circuit due to ESD.

Further, in this control rack structure, since the elongated shield beam 3 is attached to the opening 15 of the rack body 1 so as to cross the printed circuit board 2, the shield beam 3 is arranged after the printed circuit board 2 is housed. Therefore, the shield beam 3 does not become an obstacle when the printed circuit board 2 is housed, and thus the printed circuit board 2 can be easily housed in the rack body 1.

Further, since the shield beam 3 can be attached after the printed circuit board 2 is housed in the rack body 1, the conventional contact spring can be installed in advance in a required height of the rack body 1 according to the height of the printed circuit board 2. The manufacturing work is not complicated as compared with the case where it is provided at a large position, and therefore the cost is not increased.

Further, since the conductive sponge 32 is interposed between the main body 31 of the shield beam 3 and the printed circuit board 2, the printed circuit board 2 and the main body 31 can be surely brought into contact with each other, and the printed matter can be printed. The contact portion of the circuit board 2 with the shield beam 3 can be protected.

In the above-described embodiment, the case where the shield beam 3 is arranged only at one height position approximately in the middle of the printed circuit board 2 has been described. However, depending on the height dimension of the printed circuit board 2, a gap is formed. If the length of 25 is arranged so as to be shorter than the size that radio waves of the frequency within the regulation range may leak to the outside, a plurality of wires may be placed at other height positions as well as at the intermediate height position. Of course, it may be provided. For example, as shown in FIG. 3, between the upper end 21 of the printed circuit board 2 and the shield beam 3 provided at a substantially intermediate height position, and between the shield beam 3 and the lower end 22 of the printed circuit board 2. In addition, the shield beam 3 can be further provided. In this case, since the length dimension of the gap 25 formed between the adjacent printed circuit boards 2 can be further shortened, the shield effect against the radio wave of the frequency within the regulation range can be improved as compared with the above embodiment.

Table 1 shows the case where the shield beam 3 is disposed at the above-mentioned three height positions of the printed circuit board 2, the case where the shield beam 3 is not disposed at all, and the printed circuit board 2 is omitted as described above. It shows the result of examining the shield effect against the radio wave of the frequency of the regulation range in the case of arranging in the middle height position and in the case of arranging in two places other than the substantially middle height position.

[0023]

[Table 1]

As shown in Table 1, when the shield beam 3 is arranged, the shield effect is higher than when the shield beam 3 is not arranged, and when the shield beam 3 is arranged at a substantially intermediate height position. , It was confirmed that a higher shielding effect was obtained than when it was placed at two positions other than the height position approximately in the middle. In particular, it was confirmed that an extremely high shielding effect can be obtained when the shield beam 3 is arranged at all of the above three places. As is clear from the above result, a plurality of shield beams 3 are arranged so that the length dimension of the gap 25 between the adjacent printed circuit boards 2 may cause radio waves of frequencies within the regulation range to leak to the outside. By making it shorter than a certain size, the shield effect against such radio waves can be improved.

In the above embodiment, the conductive part of the shield beam of the present invention is made of a conductive sponge, but any material other than the conductive sponge can be used as long as it has conductivity.

Further, as the shield beam according to the present invention, it is possible to use a shield beam having a structure as shown in FIG. That is, in this shield beam 5, the rack main body 1 is provided along the longitudinal direction of the elongated metal main body 51.
Grooves 51a are formed at intervals substantially equal to the pitch of the printed circuit board 2 accommodated therein. A conductive contact spring 52 is provided in each groove 51a, and each contact spring 52 is formed so as to come into contact with an end portion of the printed circuit board 2 inserted in the groove 51a as described later. . The main body 51 is formed longer than the inner surface of the pair of side plates 13 located on both sides of the printed circuit board 2 similarly to the shield beam 3 and at both ends in the length direction. Each of them is provided with a mounting side 53 used when fixing the shield beam 5 to the rack body 1.

The shield beam 5 thus constructed
Is placed in the opening 15 of the rack body 1 and is placed at a predetermined height position of the printed circuit board 2 housed in the rack body 1 and screwed to the rack body 1 as in the above embodiment. Fixed by. At that time, each groove 5
The end portion of each printed circuit board 2 on the side of the opening 15 is inserted into the inside of the la 1a and arranged in a state where the end portion is in contact with the contact spring 52. Therefore, even in the control rack structure including the shield beam 5, the shield beam 5 is formed in the length direction of the gap 25 formed between the adjacent printed circuit boards 2.
Since the radio waves emitted from the printed circuit board 2 can be emitted from the shield beam 5 by means of the above-mentioned method, it is possible to obtain the same shield effect as that of the above embodiment.

In the control rack structure of this embodiment, the shield beam according to the present invention is attached to the opening side of the rack body. However, instead of the opening side, the shield beam is provided on the inner surface opposite to the opening side of the rack body. It may be attached, or may be attached to both the opening side and the inner surface opposite to the opening.

For example, as shown in FIG. 5, when the shield beam 3 is attached to the inner surface of the back plate 14, the back plate 1
Since the length of the gap formed between the printed circuit boards 2 adjacent to each other on the 4 side can be shortened, radio waves having a frequency within the regulation range generated by the printed circuit board 2 leaks out from the gap on the back board 14 side. Can be prevented. Therefore, when it is attached to both the shield beam opening 15 side and the inner surface of the back plate 14, leakage of radio waves from the gap between the printed circuit boards 2 formed on both the opening side and the back plate side is prevented. Since this can be prevented, it is possible to obtain a control rack structure having a higher shield effect.

Further, in the above embodiment, the upper end 21 and the lower end 22 of the printed circuit board 2 are connected to the top plate 1 of the rack body 1.
1. The case where the housing is housed so as to be in a conductive state with the main plate 12 has been described, but since the printed circuit board and the rack body can be brought into a conductive state only by the shield beam, the upper end portion and the lower end portion are not necessarily the rack body. The printed circuit board does not have to be housed so as to be in a conductive state with. In addition, the control rack structure of the present invention can be applied to all electronic devices using a control rack that houses a printed circuit board.

[0031]

As described above, according to the control rack structure for electronic equipment of the present invention, the conductive shield beam is attached to the rack body in a state of being in contact with all of the printed circuit boards, When the rack body is electrically grounded, the printed circuit board and the shield beam can also be electrically grounded, so that the printed circuit board can be shielded against radio waves. Further, since the shield beam is arranged so as to traverse all the printed circuit boards housed in the rack body, the shield beam is arranged between the opening of the rack body in which the shield beam is arranged and the inner surface of the rack body facing the opening. In at least one of the above, the length of the gap formed between the printed circuit boards adjacent to each other can be shortened. Therefore, even if the dimension between both ends of the printed circuit board is large, the length dimension of the gap can be made shorter than the dimension at which radio waves of frequencies within the range regulated by VCCI may leak to the outside. Since the radio waves emitted from such a printed circuit board can be emitted to the ground side through the shield beam, it is possible to reliably prevent malfunction of the housed printed circuit board due to EMI and damage to the internal circuit due to ESD. . Further, in this control rack structure, since the elongated shield beam is attached so as to cross the printed circuit board, when the shield beam is arranged in the opening of the rack body, the shield beam is arranged after accommodating the printed circuit board. Therefore, the shield beam does not hinder the accommodation of the printed circuit board, and thus the printed circuit board can be easily accommodated in the rack body.

[Brief description of drawings]

1A and 1B are diagrams illustrating an embodiment of a control rack structure for electronic equipment according to the present invention, in which FIG. 1A is a front view and FIG.
Is a sectional view taken along the line AA in (a), and (c) is (a).
6 is a cross-sectional view taken along the line BB in FIG.

FIG. 2 is a perspective view showing an example of a shield beam.

FIG. 3 is a front view showing an example in which a plurality of shield beams are arranged.

FIG. 4 is a diagram illustrating another example of the shield beam,
(A) is a plan view, (b) is a perspective view.

5A and 5B are explanatory views showing another arrangement example of the shield beam, where FIG. 5A is a perspective view of the rack body, FIG. 5B is a side sectional view of FIG. 5A, and FIG. It is sectional drawing of a state.

[Explanation of symbols]

 1 Rack Main Body 2 Printed Circuit Board 3, 5 Shield Beam 13 Side Board 14 Back Board 15 Opening 21 Upper End 22 Lower End

Claims (3)

[Claims] 1. A control rack structure for electronic equipment, wherein a plurality of printed circuit boards are accommodated in a box-shaped rack body that is electrically grounded in a substantially parallel manner at intervals. And a conductive shield beam formed between both inner surfaces of the rack body located on both sides of the printed circuit board, the shield beam having an opening in the rack body and the rack body. Mounted on the rack body in such a manner that at least one of the opening and the inner surface on the opposite side traverses all the printed circuit boards housed in the rack body and is in contact with all of the printed circuit boards. A control rack structure for electronic devices, which is characterized in that 2. The control for electronic equipment according to claim 1, wherein the printed circuit board is arranged such that at least opposite ends thereof are in contact with opposite surfaces of the rack body. Rack structure. 3. The electronic device according to claim 1, wherein a plurality of the shield beams are attached between the opposite ends of a printed circuit board housed in the rack body. Control rack structure.