JPH0782785B2 - Slide switch mounting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mounting method of a slide switch in an electronic device in which a filling material is filled.

[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.

Sometimes small electronic devices are used under various environmental conditions, such as portable radios, and the environment becomes flammable gas atmosphere or places where flammable gas atmosphere may occur. Is required to have an explosion-proof structure that does not ignite surrounding flammable gas due to sparks or heat generated by the circuit of the device.

In addition, those used outdoors are required to have a waterproof structure.

As a conventional explosion-proof and waterproof structure, the case has a completely confidential structure, and in some cases, the internal pressure of the case is slightly increased.

However, the explosion-proof and waterproof structure that makes the case a completely airtight structure is a method that is generally adopted for large-scale and high-class equipment.
The seal structure of the joint portion and the movable portion is complicated and expensive, and is unsuitable for portable wireless devices and the like that require small size, light weight, and low cost. It is also conceivable to fill the space inside the case with an epoxy resin to provide an explosion-proof and waterproof structure, but synthetic resins such as epoxy resin have the property of shrinking upon curing. Therefore, this method is used for precise electronic equipment. When used for, it may cut the wiring, and cannot be used in consideration of the reliability of the product.

Therefore, the applicant of the present invention fills the voids inside the electronic device with the low viscosity silicone rubber of the two-liquid mixing and solidifying type, and easily obtains a highly reliable sealing performance without damaging the electric circuit. The structure was proposed.

[Problems to be Solved by the Invention] In the above-mentioned seal structure, since silicone rubber penetrates into a narrow space, it is necessary to leave an appropriate space for the movable portion, that is, the operation portion such as the push switch. The part must also have sufficient sealing performance.

SUMMARY OF THE INVENTION The present invention is intended to provide a method of mounting a slide switch in the above-mentioned electronic device having a silicon rubber filling structure, in which the function of the slide switch is not impaired.

[Means for Solving the Problems] The present invention relates to a method of mounting a slide switch on an electronic device in which a filling material is filled in an inner space, in which a slide is slidably provided on a side surface of the case, A seal plate is provided on the side surface to cover the periphery so that the operating portion of the slider projects, a wiring board is attached to the case, and a switch body is mounted on the wiring board, and a slide button of the switch body engages with the operating portion of the slide. Like the above, and with the wiring board horizontal, a two-liquid mixed solidification type filler is injected to the mounting surface of the switch body, and after the filler is solidified, the switch cover and the switch are covered with a seal cover. It is characterized in that the movable part related to the above is covered, and then the liquid filling is injected into the remaining internal void.

[Operation] By solidifying the liquid filler first injected, gaps and irregularities are filled to form a new mounting surface, and the new mounting surface and the seal cover completely seal the switch body and A space for accommodating the associated movable part is formed to prevent the function of the slide switch from being hindered by the liquid filler to be injected next.

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

6 to 10 show a case where the present invention is applied to the small portable radio device of the present invention.

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.
Each push portion 7 of the above penetrates through the front panel 2 and projects. 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 mounted on the upper surface of the case 1, and the connector 11 is a connection unit.
It is connected to the front wiring board 4 via 12. A slide switch 14 is provided on the side surface of the case 1.

In the small radio device of the present embodiment, as a measure against explosion, the spaces and gaps in the case 1 are filled with liquid silicone rubber 15, 16, 17, 18 and then solidified.

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

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 electrolytic 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 floor 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 slide switch 14 will be described with reference to FIGS. 6 and 7.

The slider 20 of the slide switch 14 includes an operation plate 21 that slides along the outer surface of the front panel 2 and an operation portion 22 that projects toward the inside of the case. The operation portion 22 extends along the inner surface of the front panel 2. A slide plate 23 that slides by sliding is fixed. A seal plate 24 is provided inside the slide plate 23, and the seal plate 24 is fixed to the front panel.

The wiring board 4 is provided with a switch body 13 which is aligned so as to face the slider 20.
The slide button 25 and the operating portion 22 of the slider 20 are engaged with each other. The switch body 13 is covered with a seal cover 26.

Thus, the seal cover 26 allows the slider 20, the slide button
A space for moving the movable parts such as 25 is secured by a seal cover 26.

The mounting procedure of the slide switch 14 will be described below with reference to FIGS.

A seal plate 24 is provided inside the slide plate 23, an adhesive 27 is applied to the periphery of the seal plate 24, and sealing is performed so that liquid silicone rubber does not enter from the periphery of the seal plate 24 (first
Figure).

Next, the wiring board 4 is attached to the front panel 2. With the wiring board 4 attached, the slide button 25 of the switch body 13 engages with the operating portion 22 as described above.

With the front panel 2 placed horizontally, liquid silicone rubber 16
The switch body whose liquid surface faces the wiring board 4.
Inject until the position of 13 mounting surface is reached.

On the upper surface side (attached surface side) of the wiring board 4, there is unevenness due to the rise of solder, the protrusion of terminals of electronic parts, etc., and the mounting surface of the switch main body 13 and the upper surface of the wiring board 4 itself have a slight space. Is clear. By injecting the liquid silicone rubber 16 to the mounting surface of the switch body 13, the unevenness due to the rise of the solder, the protrusion of the terminal of the electronic component, etc. is buried, and the liquid silicone rubber 16 forms a flat surface without irregularities (second
Figure).

After waiting for the liquid silicone rubber 16 to solidify, as shown in FIG. 5, the switch body 13 is covered with the seal cover 26 whose bottom surface and the side surface of the front panel 2 are open (third embodiment).
Figure).

The solidified silicone rubber 16 becomes a flat mounting surface when the seal cover 16 is provided. Therefore, there is a gap between the periphery of the wiring board 4 and the side surface of the front panel, or solder bumps are formed on the surface of the wiring board 4 on which the switch body 13 is mounted, and irregularities due to protrusions of terminals of electronic parts are generated. Even if there is, it does not hinder the installation of the seal cover 16. or,
Since the silicone rubber 16 forms a flat mounting surface, the seal cover 16 may have a simple shape.

Place liquid silicone rubber 28 around the seal cover 26,
The joint between the seal cover 26, the wiring board 4 and the seal plate 24 is sealed (FIG. 4).

When the silicone rubber 28 around the seal cover 26 is solidified, the front panel 2 and the back panel 3 are united, and the liquid silicone rubber 18 is filled in the gap between the front panel 2 and the back panel 3 as described above.

Since the switch cover 13 and the movable parts of the slider 20 are covered with the seal cover 26, the front panel 2 and the back panel 3 are covered.
Slide switch with silicone rubber 18 filled in the space between
It does not hinder the movement of 14.

In the above-mentioned embodiment, a small portable wireless device having an explosion-proof structure has been described, but it goes without saying that it can also be applied to an electronic device having a waterproof structure.

Moreover, it is needless to say that the present invention can be carried out with a filler other than silicone rubber.

[Effects of the Invention] As described above, according to the present invention, the function of the slide switch is not impaired in the structure in which the void inside the electronic device is filled with silicon rubber.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention,
1 to 4 are schematic perspective views showing a work procedure, FIG. 5 is a perspective view of a seal cover, FIG. 6 is a front view of a portable small radio in which the present invention is implemented, and FIG. 7 is the same. Front left side view, No. 8
FIG. 9 is a plan view of the same, FIG. 9 is a bottom view of the same, and FIG. 10 is a side sectional view. Reference numeral 1 is a case, 2 is a front panel, 13 is a switch body, 14 is a slide switch, 24 is a seal plate, and 26 is a seal cover.

Claims (1)

[Claims] 1. A method of mounting a slide switch on an electronic device in which an internal space is filled with a filling material, wherein a slider is slidably provided on a side surface of a case, and an operating portion of the slider is provided on an inner side surface of the case. A sealing plate covering the periphery so as to project is provided, a wiring board is attached to the case, a switch body is attached to the wiring board so that a slide button of the switch body engages with an operating portion of the slider, and the wiring board is attached. Injecting the two-liquid mixed and solidifying type filling material to the mounting surface of the switch body in a horizontal state, solidifying the filling material, and then covering the switch body and the movable parts related to the switch by covering with a seal cover, A method for mounting a slide switch, characterized by injecting a liquid filling into the remaining internal voids.