JP2003318583A - Housing structure for transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a housing structure for a transmission device which can realize a small change over aging and good shielding characteristics at a low- cost and with a simple shielding structure having a small number of components without necessity of a special jig and a working sequence. <P>SOLUTION: A branched distributor 1 comprises: a case body 10 having steps of two differential stages along the entire area (entire periphery) of the inner peripheral side of the end of an opening 11; a cover member 20 made of a softer metal material than the metal material applied to the body 10, deforming the vicinity of the peripheral edge of the member 20 when the member 20 is press injected in the opening 11 and formed of the metal material having a hardness of the degree for bringing into substantially close contact with the stepwise part 12 provided in the opening 11; and a circuit board 30 contained in the body 10 and having a branched distributing circuit formed on the board. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a housing structure of a transmission device, and more particularly, to a leakage of a signal from the transmission circuit housed inside the housing to the outside of the housing and a mixing of a signal from the outside of the housing. The present invention relates to a housing structure of a transmission device having a shielding effect to prevent it.

[0002]

2. Description of the Related Art Conventionally, in an office building, an apartment house, etc., a co-listening receiving system, a CATV system, etc. have been used as a structure for transmitting and distributing various information such as television broadcasting to each room and dwelling unit in a building ridge. Network systems are known. In such a network system, for example, as shown in FIG. 4, a joint reception facility (or center station) 10 equipped with a reception antenna for broadcasting signals and the like is provided.
0 and each living room 200 are connected by a transmission cable 300 such as a coaxial cable or an optical cable, and various information such as a television broadcast signal received by the joint reception facility 100 is transmitted through the transmission cable 300. It

Here, as shown in FIG. 4, a booster (amplifying device) 310 for compensating the signal level of a broadcast signal to be transmitted and a broadcast signal are provided in the transmission path formed by the transmission cable 300. Etc. are divided into a single high-level signal and a plurality of low-level signals, and the high-level signal is supplied to the transmission cable 301 serving as the trunk line and the low-level signal is supplied to the transmission cable 302 serving as the branch line. In order to transmit the branching device 320, the broadcast signal and the like to the audiovisual equipment and the like (not shown) installed in each living room 200, the broadcast signal and the like are equally divided into predetermined signal levels and further divided into a plurality of branch lines. A distributor 330 that supplies the transmission cable 302
A reception terminal 340 provided in each room 200 for receiving a broadcast signal or the like transmitted via the transmission cables 301 and 302 serving as the trunk line and the branch line and outputting the received signal to an audiovisual device or the like.
Etc. are provided.

The branching device 320 and the distributor 330 (or the branching distributor having the functions of both of them) installed on the transmission path in the building ridge as described above are generally the wall surfaces of the building. It has a miniaturized structure so that it can be attached to, for example, as shown in FIG.
As shown in (b), the case 32 having a substantially rectangular parallelepiped shape.
A plurality of input terminals and output terminals (hereinafter, collectively referred to as “input / output terminals”) 322 for inputting / outputting a signal transmitted via a transmission cable (coaxial cable) are projected on the side surface 321s or the upper surface of the one. A functional circuit (branching / distributing circuit) for branching or distributing a broadcast signal or the like input / output through the input / output terminal 322 at a predetermined signal level is provided inside the case 321. The circuit board 323 is stored.

In such a branching / distributing device, a transmission loss of a broadcast signal or the like caused by leakage of a signal or an electromagnetic wave emitted from the above-mentioned branching / dividing circuit to the outside of the case, an electrical adverse effect on peripheral devices, or the like. In order to suppress an increase in noise and deterioration of a transmission signal due to the mixing of signals and electromagnetic waves from the outside of the case into the branch distribution circuit, it is desirable to have good shield characteristics. Here, in general, the electromagnetic wave generated from an electronic device (branch distributor in this case) gives a disturbance to other electronic devices as electromagnetic interference (EMI: Electr).
omagnetic Interference; To what extent it is a noise source to the outside), on the other hand, resistance to external noise is noise immunity (immunity: Noise Im
munity; the reciprocal of electromagnetic susceptibility), and standards for shielding characteristics (electromagnetic interference standards) in electronic devices are established for each country by these. Hereinafter, in the present application, the degree of the EMI and the immunity will be collectively referred to as “shielding characteristics”.

As an electromagnetic wave shielding structure (shield structure) applied to a branching distributor in the prior art, for example, as shown in FIGS. 6 (a) and 6 (b), the branching distribution as shown in FIG. Through the opening 321h formed on the bottom side of the case body 321b of the container 320A.
The circuit board 323 of the branching / distributing circuit is housed inside 1b, and a thin plate-shaped cover member 321c is provided on the step 321e at the end of the opening 321h so as to seal the space SP in which the circuit board 323 is housed. It is known that it is pressed in and closed. However, such a branch distributor 32
In the 0A shielding structure, it is difficult to realize a closed state in which the case body 321b (step portion 321e) and the press-fitted cover member 321c are evenly adhered to each other over the entire circumference of the opening 321h. As shown in the figure, there is a problem that an extremely small gap CL is generated, which causes leakage or mixing of signals and electromagnetic waves.

Therefore, in order to further improve the shield characteristics of the above-mentioned shield structure, for example, FIGS. 7 (a) and 7 (b) are used.
As shown in FIG. 5, a step portion 321f having an acute-angled cross-sectional shape is formed at the end of the opening 321h, and the cover member 321 is formed.
By pressing c into the step portion 321f, the end portion of the cover member 321c is deformed so as to bite into the step portion 321f, or as shown in FIGS. 7C and 7D. When the 321c is press-fitted into the step portion 321e, a cover member 321 is provided by using a special die DI or jig.
The end portion of c is locally deformed so as to be in close contact with the step portion 321e, or as shown in FIGS. 8A and 8B, the case main body 321b and the cover member 321c.
It is also known that a metal mesh 321j or a conductive resin material is interposed between and to improve the adhesion between the case body 321b and the cover member 321c at the step portion 321e. Regarding the shielding structure of such a branch distributor, for example,
It is described in detail in Japanese Patent Publication No.-4073, Japanese Utility Model Publication 5-8714, and the like.

[0008]

However, the inventors of the present application have made various investigations into the above-described branching distributor shielding structure. It was found that although the good shielding property is obtained immediately after the cover member is closed, the shielding property is deteriorated in some cases due to a change with time due to a change in external environment.

Specifically, in the case of the branch distributor 320A having a case shape having relatively long sides as shown in FIGS. 5B and 6, the cover member 321c corresponding to the rectangular opening 321h. It was observed that in the long side portion Lp of the above, the clearance CL is likely to occur due to the bending at the time of press fitting into the step portion 321e, and the shield characteristics are deteriorated. Here, in order to eliminate such bending of the long side portion Lp, the long side portion Lp of the cover member 321c is formed in advance so as to have a curve slightly protruding outward,
Immediately after the press-fitting of the cover member 321c into the step portion 321e, good shielding characteristics were temporarily obtained, but it is considered that the case body 3 is considered to be caused by changes in the external environment such as temperature and humidity.
It has been found that there is a problem that a gap CL is generated in the step portion 321e due to a change in shape of 21b and the cover member 321c with time, and the shield characteristic is deteriorated.
Further, in order to realize the above-described branch distributor shielding structure, a special jig or a work procedure is required when the cover member is closed on the case body, and the number of parts constituting the case is increased. There is also a problem that the product cost rises.

In view of the above problems, the present invention is an inexpensive and simple shielding structure that requires no special jigs or working procedures and has a small number of parts, but has a change over time. An object of the present invention is to provide a housing structure of a transmission device that can realize a small and excellent shield characteristic.

[0011]

According to a first aspect of the present invention, there is provided a housing structure for a transmission device, comprising: a main body having an opening for accommodating a predetermined transmission circuit; and a lid for closing the opening. In the casing structure of the transmission device, the casing has a plurality of steps on the inner circumference of the opening.

According to a second aspect of the present invention, there is provided the transmission device casing structure according to the first aspect, wherein the lid has a plurality of steps over the entire inner circumference of the opening. It is characterized in that they are press-fitted so as to be in close contact with each other and are closed in the casing. Furthermore, the case structure of the transmission device according to claim 3 is the case structure of the transmission device according to claim 1 or 2, wherein the transmission device branches and distributes a signal transmitted to a transmission cable in a cable network system. It is characterized in that it is a branch distributor.

That is, the case structure of the transmission device according to the present invention is, for example, in a branch distributor applied to a network system such as a co-listening reception system and a CATV system, and a case body (case) forming the branch distributor. A stepped portion composed of a plurality of steps is formed in the entire inner peripheral end portion of the opening portion of the body body, and a thin plate cover that closes the opening portion with respect to a horizontal plane and a vertical surface forming each of the steps. Member (lid)
It is press-fitted so that the ends of are closely attached.

As a result, the case body and the cover member are substantially evenly adhered and closed over substantially the entire circumference of the opening portion of the case body, and the generation of the gap in the step portion is suppressed, so that the branch distributor or the like is prevented. It is possible to block emission and mixing of electromagnetic waves inside and outside the transmission device, and to provide a transmission device having excellent shield characteristics. In particular, since the end portion of a single cover member is intimately and closely attached to a plurality of various surfaces forming the step portion, the shape over time due to changes in the external environment is formed. It is possible to realize a transmission device that is unlikely to change and can secure good shield characteristics for a long period of time.

Further, the above-mentioned structure according to the present invention is constituted only by the case body and the cover member, and the cover member is pressed into the opening (stepped portion) of the case body with a uniform pressing force. Since the cover member deforms and adheres to the case body almost uniformly, it has good shielding properties without increasing the number of parts that make up the case and without requiring special jigs or work procedures. A transmission device can be provided inexpensively and easily.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a housing structure of a transmission device according to the present invention will be specifically described with reference to embodiments. FIG. 1 is a schematic configuration diagram showing an embodiment of a casing structure of a transmission device according to the present invention. Here, an example will be described in which the transmission device according to the present invention is applied to a branching / distributing device installed in a transmission cable of a cable network system such as a common listening system. The housing structure of the branching / distributing device described in this embodiment is merely an example, and does not limit the present invention in any way.

As shown in FIG. 1, the branching / distributing device 1 according to the present embodiment is generally housed inside a case body (housing body) 10, a cover member (lid body) 20, and a case body 10. And a circuit board 30 on which a branch distribution circuit (transmission circuit) is formed.

Here, as shown in FIG. 1A, the case body 10 has, for example, a substantially rectangular parallelepiped shape having relatively long sides, and is made of a metal material such as aluminum die cast.
It is formed by. An opening 11 is provided on one surface side (back surface side; upper surface side in the drawing) of the case body 10, and the circuit board 30 is housed in the internal space SP of the case body 10 through the opening 11. Further, on the side surface 10s of the case body 10, the circuit board 30 housed in the internal space SP is provided.
A plurality of input / output terminals 40 for inputting / outputting signals to / from the (branching distribution circuit) are provided.

Further, in the case body 10 applied to the branch distributor according to the present embodiment, FIG.
As shown in (c), along the entire area (that is, the entire circumference) on the inner peripheral side of the end of the opening 11 provided in the case body 10, for example, from two steps (or a plurality of steps) Is formed. The step portion 12 is specifically,
Outside the opening 11 (that is, the side surface 1 of the case body 10)
The vertical plane V1 and the horizontal plane H are arranged such that the 0s side is projected to the uppermost side, and the projecting amount is reduced in a stepwise manner toward the inside of the opening 11 (that is, the inner space SP side of the case body 10).
It has a structure in which a step 12a formed of 1 and a step 12b formed of a vertical surface V2 and a horizontal surface H2 are formed.

On the other hand, the cover member 20 is the case body 10.
The metal material is softer than the metal material applied to the cover member 2 and is, as described later, at least during the press-fitting operation into the opening 11 provided in the case body 10.
0 is formed by a thin plate made of a metal material, for example, aluminum or the like, which has a hardness such that the vicinity of the peripheral edge of 0 (the end) is deformed and substantially evenly adheres to the step portion 12 provided in the opening 11. ing. That is, the cover member 20 is
As shown in FIGS. 1B and 1C, at least in a state of being press-fitted into the opening 11 provided in the case body 10,
All of the vertical surfaces V1 and V2 and the horizontal surfaces H1 and H2 forming the stepped portion 12 (steps 12a and 12b) or a plurality of surfaces are closely contacted so that they do not come into contact with each other in a complex manner and a slight gap is not generated. is doing.

It should be noted that, in the circuit board 30, a signal input via a specific input / output terminal 40 provided on the side surface 10s of the case body 10 is branched to a predetermined number on an insulating printed board, or A branching / distributing circuit for distributing and outputting via another input / output terminal 40 is formed. The circuit board 30 is housed and fixed in the internal space SP of the case body 10, and is electrically connected to the input / output terminal 40 at a predetermined circuit pattern position.

Next, the closed state of the cover member in the branch distribution unit according to this embodiment will be described with reference to the drawings. FIG. 2 is a schematic view showing a closed state of the cover member (lid) to the case body (housing body) in the branch distributor according to the present embodiment.

The branching / distributing device having the above-mentioned structure is realized by the following work and its operation. First, as shown in FIG. 2 (a), of the stepped portions 12 formed in the opening 11 of the case body 10, for example, the stepped portion 12 b formed on the innermost side is covered by the cover member 2
2 (b), at least substantially the entire area of the cover member 20 including the vicinity of the peripheral edge portion is engaged with a simple jig or the like (not shown) after the peripheral edge portion (edge portion) of 0 is engaged. And press with a substantially uniform pressing force (arrow F1).

By the press-fitting operation of the cover member 20 as described above, in the peripheral portion of the cover member 20 formed of a metal material softer than the case body 10, as shown in FIG. Vertical plane V
A deformation stress (arrow F2) is applied in the two directions and the horizontal plane H2 direction, and the peripheral edge of the cover member 20 is deformed so as to be in close contact with each of the vertical plane V2 and the horizontal plane H2.

When a pressing force (arrow F1) is further applied to the cover member 20, as shown in FIG. 2 (d),
The peripheral portion of the cover member 20 passes over the step 12b formed of the vertical surface V2 and the horizontal surface H2 which are already in close contact with each other, and in the direction of the step 12a formed adjacent to the step 12b, and the side surface 10s of the case body 10. Internal space SP
A deformation stress (arrow F3) is generated in the direction. As a result, the peripheral portion of the cover member 20 forms the vertical surface V that constitutes the step 12a.
1 and the horizontal surface H1 are further deformed so as to be in close contact with each other.

Therefore, according to the branching / distributing device of this embodiment, the cover member is substantially evenly pushed onto the stepped portion formed in the opening of the case main body even though it has a small number of parts including the case main body and the cover member. With a simple work procedure of press-fitting with pressure, the cover member is well adhered to all the surfaces of each of the plurality of steps forming the stepped portion, or to a plurality of specific surfaces, so that no gap is generated. A state can be realized.

Next, the shield characteristics of the branch distributor having the above-mentioned structure will be described in detail by comparing with the structure of the prior art. The inventor of the present application conducted various experiments on the shield characteristics of the branch distributor according to the present embodiment and the configuration of the conventional technique, and came to the following conclusions. In addition, here, as a configuration of the conventional technique, a case will be described in which the configuration illustrated in FIGS. 5B and 6 is provided. FIG. 3 is a schematic diagram showing a comparison result of the shield characteristics (the amount of signal leakage with respect to the signal frequency) in the configuration of the branch distributor according to the present embodiment and the related art.

In FIG. 3, broken line data DPa, DP
b is measurement data showing the frequency dependence of the shield characteristics in the branch distributor to which the housing structure according to the present embodiment is applied, and the polygonal line data DXa and DXb are the frequency dependence of the shield characteristics in the branch distributor in the prior art. It is the measurement data showing the sex. Here, the polygonal line data DPa and the polygonal line data DXa are measurement data indicating the shield characteristics immediately after the cover member is press-fitted into the case body, and the polygonal line data DPb and the polygonal line data DXb are after a certain period has elapsed after the cover member was press-fitted. It is the measurement data which shows the shield characteristic of.

From the experimental results shown in FIG. 3, the frequency dependence of the shield characteristic in the configuration of the prior art is almost dependent on the increase of the frequency of the input signal as shown by the broken line data DXa or DXb, and the signal leakage amount (ie, , The amount of radio wave leakage) was observed to worsen. It is considered that this is because, as shown in the prior art, the signal inside the branch distributor leaks from an extremely fine gap generated between the case body and the cover member. Therefore, a network system that transmits a high frequency signal has a problem of deteriorating the signal quality.

On the other hand, the frequency dependence of the shield characteristic in the branching / distributing device having the configuration according to the present embodiment depends on the frequency of the input signal as shown in the polygonal line data DPa or DPb. Although an increase is observed, it has been found that the absolute amount is relatively suppressed and the frequency dependence is improved as compared with the configuration of the above-mentioned conventional technique. This is because a plurality of steps 12a, 12 forming the step 12 are formed in the opening 11 of the case body 10.
b (vertical planes V1 and V2 and horizontal planes H1 and H2), the end portion of the cover member 20 is deformed and adheres in a complex manner,
As a result, the case main body 1 extends over substantially the entire circumference of the opening 11.
It is considered that 0 and the cover member 20 are closely adhered to each other and closed with almost no gap.

On the other hand, with respect to the change over time in the shield characteristic in the configuration of the prior art, as shown by the polygonal line data DXa and DXb, it is observed that as the signal frequency increases, the amount of signal leakage remarkably deteriorates. Was done. this is,
As shown in the prior art, it is considered that the cause is that a signal is leaking due to the generation of a minute gap between the case body and the cover member due to the change in the external environment of the branch distributor. To be Therefore, a network system that transmits high-frequency signals has a problem that signal quality is significantly deteriorated due to the effects of aging of equipment and changes in external environment such as climate.

On the other hand, the change over time in the shield characteristic of the branching divider having the configuration according to the present embodiment is hardly observed with the passage of time as shown by the polygonal line data DPa and DPb, and the signal changes. Almost no dependence on frequency was observed, and it was found that the shield characteristics with respect to changes over time were significantly improved over the prior art. As described above, this is because the case body 10 and the cover member 20 are in close contact with each other in a composite manner over substantially the entire circumference of the opening 11 of the case body 10, which affects the deterioration of the equipment and changes in the external environment such as the climate. It is thought that it is because it is not done.

Therefore, according to the casing structure of the branch distributor according to this embodiment, the end portion of the cover member is deformed to be substantially uniform at each of the plurality of steps provided in the opening portion of the case body. It is press-fitted so as to be in close contact, and as a result, it is in close contact over substantially the entire circumference of the open section, and the generation of gaps at the step section is suppressed, so it is possible to block the emission and mixing of electromagnetic waves inside and outside the transmission equipment. In addition, it is possible to realize a branching / distributing device having excellent shield characteristics, in which the dependency on the signal frequency and changes over time is suppressed. Particularly, since the end portion of the cover member is compositely attached to each step forming the step portion,
It is possible to realize a transmission device that is unlikely to change its shape with time due to a change in the external environment and can secure good shield characteristics for a long period of time.

In the above embodiments, the case structure of the transmission device according to the present invention is applied only to the branch distributor installed in the cable network system, but the present invention is not limited to this. However, it may be applied to other transmission equipment. In short, the present invention is a relay device (transmission device) installed in a transmission cable for transmitting a predetermined signal, and when electromagnetic waves are emitted or mixed in and out of the case, peripheral devices and signal quality are adversely affected. It can be successfully applied as a preventive measure against.

[0035]

According to the housing structure of a transmission device according to the present invention, the transmission device is configured in a transmission device such as a branch distributor applied to a network system such as a co-listening reception system or a CATV system. A step portion including a plurality of steps is formed in the entire inner peripheral end portion of the opening portion of the case body (housing body), and the opening portion is closed with respect to a horizontal plane and a vertical surface forming each of the steps. Since the ends of the cover member (lid) of the thin plate are pressed so that they are in close contact with each other substantially uniformly, the generation of gaps in the step portion is suppressed, and the emission and mixing of electromagnetic waves inside and outside the transmission device is blocked. Therefore, it is possible to provide a transmission device having excellent shield characteristics.
In particular, since the end portion of a single cover member is intimately and closely attached to a plurality of various surfaces forming the step portion, the shape over time due to changes in the external environment is formed. It is possible to realize a transmission device that is unlikely to change and can secure good shield characteristics for a long period of time.

Further, the above-mentioned structure according to the present invention can be realized by a simple structure having a small number of parts, and the cover member is pressed into the opening (step) of the case body with a uniform pressing force. Since it can be realized by a simple operation, it is possible to inexpensively and easily provide a transmission device having a good shield characteristic.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a housing structure of a transmission device according to the present invention.

FIG. 2 is a schematic view showing a closed state of a cover member with respect to a case main body in the branch distributor according to the present embodiment.

FIG. 3 is a schematic diagram showing a comparison result of the shield characteristics between the branch distributor according to the present embodiment and the configuration of the related art.

FIG. 4 is a schematic configuration diagram of a cable network system.

FIG. 5 is a schematic diagram of a branching device and a distributor (or a branching distributor) installed in a transmission path of a cable network system.

FIG. 6 is a diagram showing an electromagnetic wave shielding structure applied to a branching / distributing device according to a conventional technique.

FIG. 7 is a view (No. 1) showing a shielding structure for further improving the shield characteristic of the branching / distributing device in the prior art.

FIG. 8 is a view (No. 2) showing a shielding structure for further improving the shield characteristic of the branching / distributing device in the conventional technique.

[Explanation of symbols]

1 branch distributor 10 Case body 10s side 11 openings 12 Step 12a, 12b steps 20 cover member 30 circuit board 40 input / output terminals

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 5/00 H05K 5/00 A 5/03 5/03 B 5/06 5/06 AF term (reference) ) 4E360 AB13 AB31 BA08 BC05 BD03 CA01 EA18 ED03 ED27 FA08 GA34 GB02 GC02 5C056 FA02 FA08 GA11 HA14 JA02 JA05 5C064 BA02 BB05 BC14 5E321 AA01 CC01 GG05 5K016 AA02 BA14 DA01 DA07 EA03 EA09 GA02

Claims (3)

[Claims] 1. A casing structure of a transmission device, comprising: a main body having an opening for accommodating a predetermined transmission circuit; and a lid for closing the opening, wherein the casing is the opening. A casing structure for a transmission device, which has a plurality of steps on the inner circumference of the casing. 2. The lid is press-fitted so as to be in close contact with each of the plurality of steps over the entire inner circumference of the opening, and is closed to the housing. Of the transmission equipment housing. 3. The transmission device casing structure according to claim 1, wherein the transmission device is a branching / distributing device that branches and distributes a signal transmitted to a transmission cable in a cable network system.