JPS6343831Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a controller for an electric carpet, etc., which has a printed circuit board equipped with electronic control circuit parts for controlling the heater of the electric carpet, etc. housed in a case.

Configuration of conventional example and its problems As shown in Fig. 1, a conventional controller for an electric carpet, etc. has a printed circuit board 2 equipped with an electronic control circuit section 1 for controlling a heater of an electric carpet, etc., housed in a case 3. It was composed by Note that 4 is a metal shielding plate and 5 is a lead wire. FIG. 2 shows a block equivalent circuit diagram of a conventional controller, in which 6 is a heater connected between power line terminals X and Y, 7 is a control element that controls the energization of the heater 6, and 1 is a The electronic control circuit section 1 is connected in parallel to the series circuit of the heater 6 and the control element 7, and this electronic control circuit section 1 controls the control element 7. 8 is the earth earth.

However, with only this configuration, when noise is generated at power line terminals Because electromagnetic radiation is transmitted to the earth ground 8, the electronic control circuit section 1 malfunctions, and as a result, the control element 7 controlled by the electronic control circuit section 1 also malfunctions, causing the heater 6 to overheat or There was a problem in that the heat generation in step 6 was not performed and the operation became extremely unstable.

Purpose of the invention In view of the above-mentioned conventional problems, the purpose of the present invention is to prevent malfunctions of the electronic control circuit due to noise caused by disturbances superimposed on the power supply voltage of the power supply line and radiation noise. .

Structure of the Invention In order to achieve the above object, the present invention includes a first exterior case made of synthetic resin, which is provided with a boss portion that contacts the electronic control circuit side of the printed wiring board;
a second exterior case made of synthetic resin that is fitted with the exterior case and has a boss portion inside so as to be in contact with the copper foil portion side of the printed wiring board, the inner surface of the second exterior case; and conductive paint is applied around the boss part. According to this configuration, the copper foil part of the printed wiring board comes into contact with the second exterior case through the conductive paint applied to the surface of the boss part. Therefore, even if noise is generated due to a disturbance superimposed on the power supply voltage of the power supply line and that noise infiltrates the electronic control circuit, the conductive paint has a shielding effect from the earth. For,
There is no electromagnetic radiation to the earth, and as a result, it is possible to prevent malfunctions of heaters, such as electric carpets, controlled by the electronic control circuit section.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIGS. 3 to 5, 11 is a printed wiring board, and this printed wiring board 11 is equipped with an electronic control circuit section 12 for controlling a heater such as an electric carpet on one side, and is soldered on the other side. It has a copper foil part 13 on which this process is performed. Reference numeral 14 designates a first exterior case in which a mounting boss portion 15 that contacts the electronic control circuit portion 12 side of the printed wiring board 11 is provided inside;
Constructed from synthetic resin. Reference numeral 16 denotes a second exterior case that fits into the first exterior case 14. This second exterior case 16 is made of synthetic resin, and has internal parts facing the mounting boss portion 15 of the first exterior case 14. Attachment boss portions 17 are formed at opposite corner portions. 18
is a boss portion provided inside the second exterior case 16 so that its end is in contact with the copper foil portion 13 side of the printed wiring board 11; A conductive paint 19 is applied as shown in FIGS. 3 and 4. Further, the first exterior case 14 includes a second exterior case 1.
The boss portion 2 is placed so as to face the boss portion 18 provided in the
0 is integrally formed.

In the above configuration, when assembling the printed wiring board 11 into the outer cases 14 and 16, the printed wiring board 11 is first placed in the second outer case 16, and then the first outer case 16 is mounted on the second outer case 16. Case 1
Fit 4. After that, the second outer case 16
The first exterior case 14 and the second exterior case 1 are connected by screwing in screws (not shown) from the outer surfaces of the
6 is fixed in a sealed state. in this case,
Mounting boss portion 1 provided on the first exterior case 14
5 is provided with a screw hole (not shown), and the mounting boss portion 17 provided in the second exterior case 16 is provided with a through hole (not shown) that penetrates from the outer surface of the second exterior case 16. In addition, a printed wiring board 1
1 has these mounting bosses 1 as shown in FIG.
Since the hole 21 is provided at a position facing 5 and 17, screws can be inserted from the outer surface of the second exterior case 16 through the mounting boss portion 17 and the hole in the printed wiring board 11 to the mounting boss of the first exterior case 14. By screwing into the portion 15, the first exterior case 14 and the second exterior case 16 can be fixed, as shown in FIG.

Due to the fixing structure shown in FIG. 4, the copper foil portion 13 of the printed wiring board 11 comes into contact with the boss portion 18 provided on the second exterior case 16 via the conductive paint 19. This contact also occurs because the boss portion 20 provided on the first exterior case 14 faces the boss portion 18.
With this boss portion 20, reliability can be obtained. FIG. 5 is a cross-sectional view taken along the line A-A' in FIG. 4, and the shaded area indicates a portion at ground potential.

FIG. 6 shows a block equivalent circuit diagram of a controller in an embodiment of the present invention, in which 22 is a heater connected between power line terminals X and Y, and 23 is a control for controlling energization to the heater 22. Element 12 is an electronic control circuit unit connected in parallel to the series circuit of the heater 22 and control element 23,
This electronic control circuit section 12 controls the control element 23. 24 is the earth earth. Note that 19 indicates the ground potential due to the conductive paint.

In the circuit configuration shown in FIG. 6, even if noise is generated due to a disturbance superimposed on the power supply voltages of the power supply lines X and Y and enters the electronic control circuit section 12, the ground potential due to the conductive paint 19 has a shielding effect with the earth 24, so that electromagnetic radiation is not transmitted to the earth 24, and as a result, malfunction of the heater 22 controlled by the electronic control circuit section 12 is prevented. be able to.

Effects of the Invention As described above, according to the present invention, there is provided a first outer case made of synthetic resin, which is provided with a boss portion that contacts the electronic control circuit side of the printed wiring board, and a first outer case that is fitted with the first outer case. a second exterior case made of synthetic resin and having a boss portion therein so as to be in contact with the copper foil portion side of the printed wiring board; Since the copper foil part of the printed wiring board comes into contact with the second exterior case through the conductive paint applied to the surface of the boss part, the power line Even if noise is generated due to a disturbance superimposed on the power supply voltage and enters the electronic control circuit, electromagnetic radiation will be radiated to the earth because the conductive paint has a shielding effect with the earth. As a result, it is possible to prevent a heater such as an electric carpet, which is controlled by the electronic control circuit section, from malfunctioning. In addition, there is no need to provide special parts for shielding, and the desired purpose can be achieved with a simple structure that only requires applying conductive paint, resulting in a product with high practical value at a low cost. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a conventional controller for electric carpets, etc., Fig. 2 is a block equivalent circuit diagram of the same controller, and Fig. 3 is an exploded perspective view of a controller for electric carpets, etc. showing an embodiment of the present invention. , FIG. 4 is an assembled sectional view of the same controller, FIG. 5 is a view taken along the line A-A' in FIG. 4, and FIG. 6 is a block equivalent circuit diagram of the same controller. DESCRIPTION OF SYMBOLS 11...Printed wiring board, 12...Electronic control circuit section, 13...Copper foil section, 14...First exterior case, 16...Second exterior case, 18...Boss of the second exterior case Part, 19... Conductive paint, 20
...Boss part of the first exterior case.

Claims (1)

[Scope of utility model registration request] A printed wiring board that is equipped with an electronic control circuit section for controlling a heater such as an electric carpet on one side and has a copper foil section that is soldered on the other side, and a printed wiring board that has an electronic control circuit section on the side of the electronic control circuit section of the printed wiring board. a first exterior case made of synthetic resin having a contacting boss portion therein; and a boss portion provided therein so as to fit with the first exterior case and contact the copper foil portion side of the printed wiring board. A controller for an electric carpet or the like, comprising a second exterior case made of synthetic resin, the inner surface of the second exterior case and the surface of the boss portion being coated with conductive paint.