JPH0612640Y2 - Explosion-proof connection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an explosion-proof connecting device for connecting an external connection part and an internal circuit in an electronic device provided with an explosion-proof measure.

[Prior Art] In recent years, various small-sized electronic devices have been increasingly sophisticated, and with the adoption of microcomputers, the density of electric circuits and the voltage of circuits have been increased. In such an electronic device, sparks and heat generated in an electric circuit may cause the flammable gas to ignite.

Especially for small electronic devices that are used under various environmental conditions, such as portable radios, where the operating environment is a flammable gas atmosphere or a place where there is a possibility of a flammable gas atmosphere. It is required that explosion-proof measures be taken so that the surrounding flammable gas is not ignited by sparks or heat generated by the circuit of the device.

As explosion-proof measures, there are structural explosion-proof measures that prevent flammable gas from entering the interior, and electric circuit-based explosion-proof measures that prevent sparks and heat from being generated.

As a general structural explosion-proof measure, the case is made completely airtight.

In addition, as an electric circuit explosion-proof measure, it is possible to reduce the current value flowing through a place where a spark is expected to occur.

It will be briefly described in FIG.

In the figure, 19 indicates an electric capacity of an electronic device circuit, 20 is a power source, 21 is a current limiting circuit, 22 is a resistor, and 23 is a spark generation place where a spark is expected to occur.

When a short circuit or the like occurs at the spark generating point 23, the electric charge accumulated in the electronic device circuit flows at one time in addition to the current from the power source 20 at the spark generating point 23, and a spark is generated.

Since this spark generation is greatly affected by the current from the electronic device circuit, in order to prevent the spark generation, the resistance 22 is inserted to reduce the current to the spark generation point 23.

Further, as an electric circuit explosion-proof measure, it is also required that the distance between the conductors in the circuit (insulation space distance) is a predetermined distance or more.

[Problems to be Solved by the Invention] As a structural explosion-proof measure, the present applicant fills voids inside electronic equipment with a low viscosity silicone rubber of a two-liquid mixture solidification type to easily damage the electric circuit. I proposed an explosion-proof structure.

The present application further seeks to provide an explosion-proof connection device between an external connection portion and an internal circuit as one of electric circuit explosion-proof measures.

[Means for Solving the Problems] The present invention relates to an explosion-proof connecting device for connecting an external connection part and an internal circuit of an explosion-proof electronic device, wherein the external connection part and the internal circuit are connected by a flexible substrate, A conductive pattern having a resistor is formed on the substrate, and insulating plates are provided on both sides of the flexible substrate so as to sandwich the resistor.

[Operation] The resistance provided on the flexible substrate suppresses the generation of sparks, and the insulating plates on both sides of the flexible substrate maintain the insulating space distance required between the conductive portions.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

First, referring to FIG. 4 to FIG. 8, a portable small wireless device provided with the structural explosion-proof measures of the silicon rubber filling method proposed by the present applicant will be described.

The case 1 of this portable small radio has a front panel 2 and a back panel 3 which are divided into two parts.
Wiring boards 4 and 5 on which electronic components are mounted are attached.

A push switch unit 6 is attached to the wiring board 4 on the front panel 2 side, and each push portion 7 of the push switch unit 6 penetrates the front panel 2 and projects therefrom. A shield cover 8 is fixed to the wiring board 5 on the back panel 3 side.

An antenna 9, a push button switch 10, and a connector 11 are attached to the upper surface of the case 1, and the connector 11 is an explosion-proof connecting device.
It is connected to the front wiring board 4 via 12. A slide switch 14 for adjusting the variable resistor 13 is provided on the side surface of the case 1.

As mentioned above, in this portable compact radio, liquid silicone rubber 15,16,17,1
Fill 8 and then solidify.

Silicon rubber 15,16,17,18 used for such filling,
A two-liquid mixture solidification type that does not change in volume during solidification is used, and a low viscosity (for example, 20 poise) is adopted so that it can sufficiently penetrate into even small gaps.

In addition, it takes time to fill air so that it is difficult to contain air when it is filled and it is easy to escape when air is filled.
It also gives a sufficient solidification time.

Here, as a filling method, it is preferable to use a nozzle or the like and to gravity drop naturally without applying pressure at the time of injection. If the injection is performed by natural dropping, the speed at which the injected liquid silicone rubber permeates and the injection speed can be matched, and a completely dense state can be filled.

Thus, when the silicone rubber is solidified, the voids in the case 1 are completely filled with the silicone rubber, and the outside air and the spark generation part of the electric circuit are cut off from the heat generating part, and the outside air is a flammable gas atmosphere. However, it does not catch fire due to the electric circuit.

Although the heat of the heat generating portion is diffused by the silicone rubber, powder of alumina oxide having excellent thermal conductivity may be mixed with the silicone rubber in order to perform the thermal diffusion more effectively.

As described above, since the two-liquid mixing type silicone rubber does not change in volume, local strain and residual stress due to the strain do not occur in the solidified state. Therefore, fine wiring patterns, lead wires, etc. can be formed. Never disconnect. Further, since the silicone rubber is highly elastic in the solidified state, even if strain occurs, it is absorbed by the deformation of the silicone rubber itself, and the wiring pattern,
It does not lead to cutting of lead wires.

Next, the explosion-proof connecting device according to this embodiment will be described with reference to FIGS. 1 and 2.

The same parts as those shown in FIGS. 4 to 8 in FIGS. 1 and 2 are designated by the same reference numerals.

In the figure, reference numeral 26 denotes a flexible board, and the flexible board 26 has two connecting portions 27 and 28, and one connecting portion 27 is fixed to the connector 11 which is an external connecting portion and the other connecting portion is provided. 28 is fixed to a board connector 29 that is connected to a connector pin (not shown) implanted in the wiring board 4.

Conductive patterns (not shown) for connecting the connection pins of the connector 11 and the connection pins of the board connector 29 are formed on the flexible board 26.

An explosion-proof resistor 30 is provided in the middle of each conductive pattern. A back insulating plate 31 having a plate thickness equal to or larger than a required insulating space distance is attached to the back side of the flexible substrate 26, and a front insulating plate is provided on the front side of the flexible substrate 26 so as to sandwich the resistor 30.
32 is provided. A space between the front insulating plate 32 and the flexible substrate 26 is filled with a two-liquid mixed type silicone rubber 33. The silicone rubber 33 is eroded to both the connecting portions 27, 28 side. The projecting portion 34 reduces stress concentration at the base ends of both the connecting portions 27, 28 and prevents the flexible substrate 26 from being broken.

Needless to say, the front insulating plate 32 has a plate thickness equal to or larger than the required insulation space distance, like the back insulating plate 31.

By connecting the board connector 29 to a connector pin (not shown) of the wiring board 4, the connector 11 is tangentially connected to the circuit of the wiring board 4 via the flexible board 26.

In the above structure, the connector 11 is exposed to the outside air, and there is a possibility that sparks will be generated when the cable side connector is attached or detached. Therefore, the connector 11 corresponds to the spark generation point 23 in FIG.

In order to prevent sparks at the connector 11, the explosion-proof resistor 30
Is provided.

Further, it is unclear what posture and position the flexible substrate 26 should have when filling the inside of the electronic device with silicon rubber, but since the insulating plates 31 and 32 are provided on both sides, the flexible substrate 26 has electrical continuity. The part does not approach more than the insulation space distance required between other conducting parts.

Thus, complete explosion-proof measures are taken in the connection between the connector 11 and the internal circuit of the electronic device.

In addition, although the above-described embodiment describes the electronic device having the silicon rubber filling structure, it goes without saying that the electronic device having the airtight structure can also be implemented.

[Advantages of the Invention] As described above, according to the present invention, since the flexible board is provided with the resistor, it is possible to prevent the generation of sparks due to the disconnection of the external device to the external connection portion, and to provide the flexible board on both sides. The insulating plate provides the necessary insulation space between the conductors, and the explosion-proof measures in the connection between the external connection part and the internal circuit can be realized, and the structure is simple and the explosion-proof measures are reliable. Shows excellent effects.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a front side view of the same, FIG. 3 is a circuit diagram showing an example of explosion-proof measures, and FIG. 4 is a small portable device in which the present invention is implemented. Front view of radio, 5th
FIG. 6 is a left side view of the same, FIG. 6 is a plan view of the same, FIG. 7 is a bottom view of the same, and FIG. 8 is a side sectional view. 12 is explosion-proof connecting device, 26 is flexible board, 30 is resistor,
31 is a back insulating plate, 32 is a front insulating plate, and 33 is a silicon rubber.

Claims (3)

[Scope of utility model registration request] 1. An explosion-proof connecting device for connecting an external connection part and an internal circuit of an explosion-proof electronic device, wherein the external connection part and the internal circuit are connected by a flexible board, and the flexible board is provided with an intermediate resistor. An explosion-proof connecting device, characterized in that a conductive pattern is formed, and insulating plates are provided on both sides of the flexible substrate so as to sandwich the resistance. 2. The explosion-proof connecting device according to claim 1, wherein the thickness of the insulating plate is not less than the required insulating space distance. 3. The explosion-proof connecting device according to claim 1, wherein silicon rubber is filled between the flexible substrate and the insulating plate.