JPH01273391A - Protective case of electric-heater temperature control section - Google Patents

Abstract

PURPOSE:To interrupt the specific region of the rear of a printed board surrounded by the plane section of a first case and the surface of the printed board surrounded by the wall surface of a second case from the outside air by pushing and fast sticking the printed board onto the plane section of the second case by the wall surface of the first case. CONSTITUTION:When a case 2 and a case 3 are combined while a printed board 4 is arranged into the inside, the outermost whole circumference of the specific region of the rear of the printed board 4 is fast stuck to the plane section of the case 2 set up so as to correspond to the outermost whole circumference because the printed board 4 is pushed toward the case 2 by the wall surface of the case 2. The pushing force to the printed board 4 of the wall surface of the case 2 represents reaction to compressive stress generated at a time when the case 2 and the case 3 are combined, and the wall surface of the case 3 pushes the surface of the printed board 4, thus also attaching the surface of the printed board 4 and the wall surface of the case 3 closely.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a protective case for a temperature control unit of an electric heating device such as an electric blanket.

BACKGROUND OF THE INVENTION A conventional protective case for a temperature control unit of an electric heating device, such as a controller for controlling the temperature of an electric blanket, is shown in FIGS. 8 and 9.
As shown in the figure, in the internal space created by combining case A2 and case B3, place a flat printed circuit board 4 so that the surface 5 on which the electronic components are placed is on the case A2 side, and on the case A2 side. It is installed so that the back side 6 on which the copper foil pattern is drawn is facing. Note that 7 in the figure is a knob.

Further, the printed circuit board 4 is installed in the case A as shown in FIG.
It is held within the space created by case A2 and case B≦ by ribs 14 at several locations that protrude inward from case A2 and case B≦.

Problems to be Solved by the Invention Normally, electric blanket controllers are placed near futons where dust such as cotton dust is likely to be generated, and in places where dust is likely to accumulate, such as on tatami mats. Dust easily enters the interior through the gap between the case B3 and the knob 7 as shown in FIG. 10 and accumulates on the inner bottom surface of the case A2.

In addition, since the controller 1 itself is not fixed, the way it is placed is not uniform. For example, if the case B3 is placed on the tatami 8 side as shown in FIG. 11, as shown in FIG. 10. All the dust that had accumulated on the bottom of the case A2 would adhere to the back side 6 of the printed circuit board 4, so the distance between the copper foils on the back side 6 is regulated to be 2.5 mm or more based on the Electrical Appliance and Material Control Law. There is a problem in that the size of the controller 4 becomes large, and therefore the controller 1 itself becomes large, making it difficult to use.

Therefore, in order to prevent dust from entering the controller 1, it is necessary to
For example, a packing 15 made of rubber or the like may be embedded between the case A2 and the printed circuit board 4 shown in FIG.
If a method is adopted in which the necessary parts of the back surface 6 of the printed circuit board 4 are coated 16 with resin or the like, the distance between the copper foils on the back surface 6 can be set to 1.5 mm or more based on the Electrical Appliance and Material Control Law.
Although the dimensions of the printed circuit board 4 can be reduced and the size of the controller can also be reduced, there is a problem in that the cost increases.

The present invention takes the above-mentioned problems into consideration and aims to provide a protective case for a temperature control unit of an electric heating device that does not increase cost, complies with the provisions of the Electrical Appliance and Material Control Law, and is small in size.

Means for Solving the Problems The present invention provides a case A having a flat printed circuit board, a flat part at the inner bottom that receives the entire outermost periphery of a specific area on the back surface of the printed circuit board, and The case A has a wall surface on its inner top surface which is pressed from a surface corresponding to the entire outermost periphery of the case A, and the printed circuit board is pressed into close contact with the flat surface of the case A by the wall surface of the case surface.

Effect With the above configuration, when case A and case day are combined with a printed circuit board placed inside, the printed circuit board is pushed toward case A by the wall surface of case day, so that the printed circuit board is The entire outermost periphery of the specific area on the back surface is in close contact with the flat part of case A provided to correspond thereto. Moreover, the force that the wall of the case presses against the printed circuit board is a reaction force to the compressive stress that occurs when case A and the case are combined, and the wall of case B presses the surface of the printed circuit board, so the printed circuit board The surface of case B also comes into close contact with the wall of case B. In other words, the force pushing the printed circuit board is not related to gravity, so no matter how the protective case of the temperature control unit of the electric heating device is placed,
The entire outermost periphery of the specific area on the back of the printed circuit board and case A
The flat surface of the printed circuit board and the wall of case B are always in close contact with each other.

Therefore, the specific area on the back side of the printed circuit board surrounded by the flat part of case A and the surface of the printed circuit board surrounded by the wall of case A are shielded from the outside air, so dust does not enter, and according to the Electrical Appliance and Material Control Law Based on
．． The standard of 5 mrn or more will be applied, making it possible to reduce the size of the printed circuit board. Therefore, the size of the electric heating device temperature control unit protective case itself can be reduced at the same cost as the conventional electric heating device temperature control unit protective case, and the usability is improved.

EXAMPLE An example of the present invention will be described in detail below with reference to FIGS. 1 to 8. Note that parts that are the same as those in the conventional example are given the same reference numerals.

FIG. 1 is a perspective sectional view showing an embodiment of the electric heating device temperature control unit protective case of the present invention.

As shown in FIG. 1, the case A2 is provided with a flat part 9 to receive the back surface 6 of the printed circuit board 4, and this flat part 9 covers the printed circuit board 4 as shown in FIGS. The entire outermost periphery 1o of a specific area on the back surface 6 of the holder is received. Note that the specific area is an area where dust is not desired to enter, and in the embodiment, it is a part of the printed circuit board, but in some cases, it may be the entire printed circuit board.

In addition, in FIG. 1, 3 is a case day, and a wall surface 11 is provided to press the printed circuit board 4 toward the case A2, and this wall surface 11 corresponds to the printed circuit board 4 in FIG.
As shown in FIG. 4, it is provided at a position corresponding to the entire outermost periphery 10 of a specific area on the back surface 6 of the . Figure 5 shows wall surface 1
FIG. 1 is an enlarged cross-sectional view of 1, in which a burr-like protrusion 12 is provided at the tip of the wall surface 11. In addition, the height of the wall surface 11 is determined by taking into consideration variations during molding and assembly, as shown in FIG.
The burr-like protrusion 12 at the tip of the wall surface 11 is set so as to contact the surface 5 of the printed circuit board 4 before the wall surface 11 comes into contact with the surface 5 of the printed circuit board 4.

By doing this, when the fitting surfaces 13 around the case A2 and the case BS come into contact as shown in FIG.
When the tip of the burr-like protrusion 12 hits the front surface 5 of the printed circuit board 4, compressive stress is generated to the extent that the printed circuit board 4 is crushed, and the printed circuit board 4 is pushed toward the case A2 by the repulsive force, and the back surface 6 of the printed circuit board 4 is crushed. The entire outermost periphery 10 of the specific area is in close contact with the flat part 9 of the case A2. Further, the wall surface 11 also comes into close contact with the surface 5 of the printed circuit board 4 by crushing the tip of the burr-like projection 12 at the tip.

Therefore, as shown in FIG. 1, even if there is a through hole 14 in a specific area on the back surface 6 of the printed circuit board 4, the printed circuit board 4 is surrounded by the specific area on the back surface 6 of the printed circuit board 4 and the wall surface 11 of the case B3. Since the area of the front surface 5 is isolated from the outside air, dust does not enter.Therefore, based on the Electrical Appliance and Material Control Law, the distance between the copper foils on the back surface 6 can be designed to be 1.5 mm or more, and the printed circuit board Since the dimensions of the controller 4 can be reduced, the size of the controller 1 itself can also be reduced at the same cost as the conventional controller, making it easier to use.

Effects of the Invention As is clear from the description of the embodiments above, the present invention includes a flat printed circuit board, a case A having a flat portion that receives the entire outermost periphery of a specific area on the back surface of the printed circuit board, and The case has a wall surface that presses the entire outermost periphery of a specific area on the back side to the flat surface of case A from the surface of the printed circuit board, and the printed circuit board is pressed tightly onto the flat surface of case A with the wall surface of case B. With this simple configuration, the size of the printed circuit board and the protective case for the temperature control unit of the electric heating device can be reduced and the usability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective sectional view showing a protective case of a temperature control unit of an electric heating device according to an embodiment of the present invention, and FIG. 2 is a plan view of the protective case of the temperature control unit of the electric heating device, Figure 3 is a sectional view of case A of the protective case of the temperature control section of the electric heating device, Figure 4 is a plan view of case B of the protective case of the temperature control section of the electric heating device, and Figure 5 is a cross-sectional view of case B of the protective case of the temperature control section of the electric heating device. An enlarged cross-sectional view of the wall surface of the protective case of the temperature control section of the electric heating device; Figures 6 and 7 are cross-sectional views of the fitted state of the protective case of the temperature control section of the electric heating device; FIG. 9 is a perspective sectional view of the protective case of the temperature control section of the conventional electric heating device, and FIG. 10 is a plan view of the protective case of the temperature control section of the conventional electric heating device.
FIG. 11 is a cross-sectional view of the protective case of the temperature control section of a conventional electric heating device; FIG. FIG. 2 is a perspective sectional view of an example of a protective case in which dustproof measures are taken. 1...Controller, 2...Case A,
3... Case date, 4... Printed circuit board, 5... Front side, 6... Back side, 9...
...Plane part, 11...Wall surface. Name of agent: Patent attorney Toshio Nakao (1 person)
---Case A 3-Booth B 4-Print F base plate 6-Back surface 7-Knob q--One plane part 11--One wall surface Fig. 1/ Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Figure 8 Figure 7 Figure 9 Figure 1O Figure 11

Claims (3)

[Claims] (1) Case A having a flat printed circuit board, a flat part on the inner bottom that receives the entire outermost periphery of a specific area on the back surface of the printed circuit board, and a case A that receives the entire outermost periphery of a specific area on the back surface of the printed circuit board A case B having a wall surface on the inner top surface that is pressed from the surface of a printed circuit board on a flat part of the case A, and the printed circuit board is pressed tightly onto the flat part of the case A with the wall surface of the case B. A protective case for the temperature control part of the heating device. (2) The specific area on the back surface of the printed circuit board and the area on the surface corresponding thereto are configured to be blocked from outside air by the flat surface and inner bottom surface of case A, and the wall surface and inner top surface of case B. A protective case for the temperature control part of the electric heating device described in paragraph 1. (3) A protective case for a temperature control unit of an electric heating device according to any one of Claims 1 and 2, wherein a burr-like protrusion is provided over the entire tip of the wall surface of the case B.