JPS636896A - Printed board device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrical method*m and a printed circuit board device mounted on a dishwasher or the like.

2. Description of the Related Art Conventionally, printed circuit board devices installed in electric washing machines, dishwashers, etc. have had structures as shown in FIGS. 3 to 5.

In FIG. 3, reference numeral 7 denotes a printed circuit board made of paper phenol or the like, and on its surface are resistors, diodes, etc. 7 electrical parts 8, chip-type parts 9. Various electrical components such as semiconductor components 10 are mounted. Reference numeral 11 denotes an electrically insulating and waterproof solvent-based paint, which is formed as a coating layer on the surface of the printed circuit board 7, the conductor portions of various electrical components, and the surfaces of the component bodies.

However, as shown in FIG.
If the length is relatively long, the coating layer may not be formed sufficiently due to variations in the viscosity during application of the electrically insulating and waterproof paint and in the application process.

For this reason, conventionally, the configuration as shown in FIGS. 4 and 5,
That is, the configuration is shown in which the conductor part 10a of the semiconductor component 10 is completely covered by partially applying the highly thixotropic electrically insulating and waterproof paint 12 to the conductor part 10a.

In FIG. 5, the coating layer is formed by a casting method instead of the coating layer formation method using a solvent-based paint as used in FIGS. 3 and 4.

In FIG. 5, reference numeral 13 denotes an electrically insulating and waterproof filler, and in this method, the liquid surface of the filler I3 is set at a height such that the conductor portion 10a of the semiconductor component IO can be completely covered.

Problems to be Solved by the Invention In the conventional method, the semiconductor component shown in FIG. The method of partially applying the paint 12 with high thixotropy to the conductor portion 10a of the conductor section 10a requires complicated work, and when a plurality of locations are to be coated, additional work steps are required. Furthermore, when the coating work is done manually, coating leakage occurs, and extra man-hours are required to check the coating.

Furthermore, the casting method shown in FIG. 5 has the following problems. That is, in the casting method, as shown in FIGS. 6 and 7, a printed circuit board device 15 with various electrical components mounted inside an injection mold 14 made of synthetic rubber or the like is set as shown in the drawings.

Thereafter, the filling material tS is injected into the injection mold 14 and solidified, and the injection mold 14 is removed to form the structure as shown in FIG. 7. As is clear from FIG. 7, for example, printed circuit board'? If there is a part 17 with a long conductor part mounted on the device 15, it is necessary to increase the number of injections of the filler 16 to raise the liquid level with the filler 16. A large amount of filler material 16 is required for the component 17 having such a long conductor portion, leading to an increase in cost. In addition, in order to reduce the amount of filler I6 as much as possible,
For example, filler material 1 is placed near the bottom of the main body of the long conductor part 17.
If the liquid level of 6 is set, pour the filler IB into the injection mold 1.
If the injection mold 14 is tilted for some reason when injecting and fixing the resin into the mold 4, a coating defect as shown in FIG. 8 may occur. In order to prevent such a phenomenon, it is necessary to inject a large amount of the filler 16, which causes problems such as an increase in the amount of the filler 1B, leading to an increase in cost.

Means for Solving the Problems In the present invention, a molded material made of a porous material that exhibits capillary action is disposed so as to cover the legs of electrical components installed upright on a printed circuit board, and the surface of the printed circuit board and the molded material are covered. A printed circuit board device was obtained in which the porous portions were filled and solidified with a filler having electrical insulation and waterproof properties.

Effect 'iii:' By placing a mold material molded from a porous material that causes capillary action in the leg of part A, when a liquid filler is injected, the gap between the leg of the electrical component and the mold material is filled. The filler infiltrates and further infiltrates the porous portion toward the lower part of the electrical component body due to capillary action. This makes it possible to reliably cover the leg portions of the electrical component, that is, the conductor portions, with the filler regardless of the quality of the filler.

EXAMPLES Hereinafter, the present invention will be explained in detail based on FIGS. 1 and 2. In Fig. 1, l denotes a printed circuit board, on the surface of which are mounted 7xial components 2 such as resistors and diodes, chip type components 3, and semiconductor components 4 such as three-way thyristors, which constitute the printed circuit board device. are doing.

Reference numeral 5 denotes a molded material made of a porous material that exhibits capillary action, and is attached so as to cover the leg of an electrical component having a long conductor portion 4a, such as the semiconductor component 4.

Reference numeral 6 is a filler having electrical insulation and waterproof properties (hereinafter referred to as filler), which is filled into the mold material that covers the surface of the printed circuit board 10 and the conductor parts of the various electrical components 2 to 4, the surface of the main body of the component, and the legs. It has solidified. This ensures prevention of corrosion due to adhesion of water droplets from the outside and malfunctions due to leakage of component conductors 1iFf from each other.

In the present invention, when two to four various electrical components are mounted on a printed circuit board l, a component having a structure like the semiconductor component 4, that is, a plurality of conductor parts 4a, is used, and the conductor parts are For parts where high voltage is applied between the conductors, the distance between the conductors is relatively narrow, and the conductors are long, the second
As shown in the figure, a mold material 5 made of a porous sponge material is attached to cover the conductor portion 4a of the component 4.

Next, the filler material 6 is filled and solidified as shown in FIG.

As the filler 6, for example, a two-component reaction curing type urethane or the like is used. - In general, the filler 6 for injection has a viscosity of 13 at room temperature.
It is in a liquid state of about 0.00 cps, and after being filled, it is solidified by heat treatment.

In the present invention, by attaching the mold material 5 as shown in FIG. The liquid filler 6 fills the part 4 by capillary action in the porous portion existing between the mold material 5 and the conductor portion 4a.
It rises towards the bottom of the main body.

Finally, the filler 6 penetrates into the gap between the mold material 5 and the conductor portion 4a of the component 4 and the gap between the lower part of the component 4 body and the mold material 5, and the target conductor portion of the component 4 is filled with the filler 6. Insulation by the filler 6 of 4a can be achieved.

If the pores are continuous, the capillary phenomenon due to the presence of the mold material 5 will occur as long as the upper surface of the printed circuit board 1 and the lower surface of the mold material 5 are immersed.
It is no longer necessary to set the height from the top surface to such a height that the entire conductor portion 4a of the component 4 is covered. In other words, the presence of the mold material 5 makes it possible for the filler 6 to selectively and reliably infiltrate and cover a component having a long conductor portion, such as the component 4.

Therefore, when mounting a component having a relatively long conductor portion 4a such as the component 4 on the printed circuit board 1 as in the conventional example, the filler 6 should be filled to a height that can completely cover the conductor portion 4a. There is no need for solidification, less material is required, and a reliable coating can be achieved.

Effects of the Invention In the present invention, a mold made of a porous material is disposed on an electrical component having a relatively long conductor portion, and then a filler is filled.
By solidifying it, it was possible to reliably cover the inside of the pores and the entire surface of the printed circuit board.

Therefore, it has become possible to selectively increase the amount of filler for each component and increase the height from the surface of the printed circuit board. In addition, unlike conventional filling processes, the process may vary due to the tilt of the printed circuit board, etc.
Insulation failure, that is, a phenomenon in which the coating layer is not formed on the conductor portion, can be prevented.

In addition, this allows the height of the filler to be adjusted regardless of the length of the conductor part of the electrical component, making it possible to reduce the amount of filler and reducing costs. The larger the area, the more effective this effect is.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of a printed circuit board device in which the mold material of the present invention is attached to the leg of a component, and FIG. 2 is a perspective view showing the specific shape of the mold material and how it is mounted on three printed boards. , FIGS. 3 to 8 are cross-sectional views showing conventional techniques, and FIG. 3 is a cross-sectional view showing a structure in which an insulating coating layer is formed using a solvent-based electrical insulating paint, and FIGS. 4 and 5. is a cross-sectional view showing a configuration in which a filler is injected to insulate the conductor part of the component, Figures 6 and 7 are cross-sectional views showing the procedure for filling with the filler, and Figure 8 is a diagram showing the filling process with the filler. FIG. 3 is a cross-sectional view showing poor coverage caused by tilting of the injection mold during processing. 1... Printed circuit board 2-4... Electrical components 4a.
...Conductor portion as a leg portion 5...Shape material 6...Filling material Applicant Matsushita Electric Industrial Co., Ltd. Agent Patent attorney Oshima - Ko No. 30 Figure 5 M7 Figure 8

Claims (2)

[Claims] (1) A molded material made of a porous material that exhibits capillary action is arranged so as to cover the legs of electrical components installed upright on a printed circuit board, and the surface of the printed circuit board and the porous portion of the molded material are provided with electrical insulation and waterproof properties. 1. A printed circuit board device characterized by being filled and solidified with a filler comprising: (2) The printed circuit board device according to claim 1, wherein a molded material made of a porous material has a shape that maintains a constant gap between the lower part of the electrical component and the printed circuit board.