JPH0964549A - Housing having vents for electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool a heating device disposed in a limited housing for electronic apparatus. SOLUTION: In order to produce an air flow even in a limited housing, the housing for electronic apparatus is provided, in the bottom plate and top plate thereof, with vents 5b, 5c corresponding to the vents 5a made in a circuit board. Consequently, the air is taken into the housing through the vents to produce an air flow for cooling the electronic devices effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation structure for electronic equipment.

[0002]

2. Description of the Related Art Cooling of electronic parts in a housing of an electronic device has always been an essential matter, but since the device has a dimensional allowance, the inside of the housing 60 is indicated by an arrow in FIG. It was not so important because it was able to exchange heat with the convection of air and was cooled. FIG. 4 is an external view showing a circuit board unit 10 of the invention disclosed in Japanese Utility Model Laid-Open No. 5-55590, which is a conventional printed circuit board for obtaining a heat dissipation effect of a heat dissipation plate 30 to which a heat generating component 20 is attached. Instead of notching 40, a press hole 50 for ventilation is provided in the printed circuit board 40 immediately below and around the heat sink 30.
In order to reduce the man-hours for processing the printed circuit board 40 and the die cost while maintaining the heat dissipation effect. However, miniaturization of electronic devices has become essential in recent years,
Although the heat generation of electronic components has been improved, there are cases where the heat generation cannot be reduced depending on the circuit, and even in that case, it may be inevitable that the heat sink is downsized and the space inside the housing is reduced. In that case, the convection of air in the housing is not sufficiently performed and the heat release becomes insufficient,
The problem of impairing the characteristics of equipment has also arisen.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and an electronic device in the case where the heat dissipation plate cannot be made sufficiently large, the space in the housing is small, and air convection cannot be expected. To provide a heat dissipation structure.

[0004]

In an electronic device including a circuit board on which heat-generating components are arranged and a housing for housing the circuit board, a housing for allowing outside air under a bottom plate of the housing to flow into the housing. The first ventilation hole provided in the bottom plate of the body, the second ventilation hole provided in the circuit board for guiding the air flowing in from the first ventilation hole to the heat generating component, and being heated by the heat generating component There is provided an electronic device casing having a third ventilation hole provided in the casing top plate for discharging the air inside the casing to the outside of the casing. In addition, an electronic device housing in which the heat generating component is an electric resistance and / or a power element is provided. Also, an electronic device housing in which the heat generating component is a heat dissipation plate of the power element is provided. Further, there is provided an electronic device housing in which the first ventilation hole is located directly below the second ventilation hole, and the third ventilation hole is displaced from directly above the component. In addition, an electronic device housing having a gap between the printed board and the housing lower cover of 5 mm to 20 mm is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is an external view showing an electronic device 1 according to an embodiment of the present invention. Reference numeral 5a is arranged immediately below and around the heat radiating plate 3 in order to enhance the heat radiating effect of the heat radiating plate 3 to which the heat generating component 2 is closely attached. The air holes are provided in the printed circuit board 4, and are punched by press working. The shape and size of the hole may be any as long as a jet of solder does not occur from the hole to the component surface when flowing through the solder bath, but considering the flow of the mold and air, it is preferably 8 mm or less in a circular shape. The number and arrangement of the holes are set within the range where the heat dissipation effect is exhibited, but the near air holes have a function of directly cooling the heat-generating components, and the far air holes cool those that have been heated by radiant heat. In this embodiment, for example, the fuse resistance is 3 mm and the heat dissipation plate is 6 depending on the heat generation amount of the electronic component.
A circular hole having a diameter of mm was used, and a vent hole was arranged within a range of 20 mm from the heat dissipation plate. In FIG. 2, the air holes 5b of the bottom plate 6a of the casing are made to correspond to the air holes 5a of the printed circuit board 4 and the arrows indicate the flow of air. However, the position just below this position does not mean the dimensional equivalent as long as it is within the range where the air flow is generated (a gap between the printed circuit board and the housing bottom plate). The air warmed by the electronic components and the heat dissipation plate becomes lighter and is emitted to the outside of the housing from the ventilation hole 5c of the top plate 6b of the housing, and the air below the printed board 4 is passed through the ventilation hole 5a of the printed board 4 into the empty space. Will be introduced. But,
Since the bottom of the printed circuit board 4 of the housing is as narrow as 5 to 20 mm, no convection occurs and the air here hardly moves. Most of the air is the air outside the housing introduced from the air holes 5b of the housing bottom plate 6a directly below the printed circuit board 4, and contributes to the cooling of the electronic components 2 and the heat dissipation plate 3. It is ideal that the vent hole 5c of the top plate 6b of the housing is right above, from the viewpoint of air flow, but depending on the environment, dust or dirt may be deposited on the heat-generating component 2 or the heat-radiating plate 3 on the printed circuit board 4. However, in that case, the cooling effect is rather reduced, so the vent hole 5c is opened in a portion where there are few parts that obstruct the air flow.
However, a gap for accommodating a relatively large electronic component such as a radiator plate or an electrolytic capacitor is required in the housing on the upper side of the printed circuit board 4, and it is easy to move air in the gap.

[0006]

EXAMPLE An example of the present invention is a scramble decoder unit of a BS decoder, in which the gap below the printed circuit board of the housing is 8 mm and the gap above is 50 mm. The main heat generating part is the power IC for constant voltage power supply of the power supply part,
Ventilation holes of 5 mmφ are placed 10 mm below and below the heat dissipation plate to which the IC is adhered, and the ventilation holes are provided at positions corresponding to the bottom plate of the housing just below the ventilation holes to achieve a sufficient cooling effect. I was able to get it.

[0007]

EFFECTS OF THE INVENTION Even in a narrow case in which air convection does not easily occur by providing a ventilation hole in the circuit board and providing a ventilation hole just below the ventilation hole so as to correspond to the bottom plate of the case,
It is possible to take in air from the outside of the housing and send the air to the heat-generating component and the heat radiating plate, thereby enhancing the heat radiating effect and cooling the electronic component.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view of a main part of an electronic device housing according to the present invention.

FIG. 2 is a cross-sectional view showing the flow of air in the electronic device casing of the present invention.

FIG. 3 is a sectional view showing a flow of air in a conventional electronic device casing.

FIG. 4 is a perspective view of a conventional circuit board unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic device housing (enlarged part of main part) 2 Heat generating component 3 Radiating plate 4 Circuit board 5a Second ventilation hole 5b First ventilation hole 5c Third ventilation hole 6a Housing bottom plate 6b Housing top plate

Claims (5)

[Claims] 1. A circuit board on which a heat-generating component is arranged, and a housing for housing the circuit board. In the electronic device, a first vent hole provided on a bottom plate of the housing, and the circuit board. A second ventilation hole provided in the housing, and a third ventilation hole provided in the housing top plate for discharging the air in the housing heated by the heat-generating component to the outside of the housing, An electronic device housing, wherein the outside air taken in from the bottom plate is applied to the heat-generating component and discharged from the top plate. 2. The electronic device casing according to claim 1, wherein the heat-generating component is an electric resistance and / or a power element. 3. The electronic device casing according to claim 1, wherein the heat generating component is a heat dissipation plate of the power element. 4. The first ventilation hole is located directly below the second ventilation hole, and the third ventilation hole is located off the position directly above the heat-generating component. The electronic device housing according to 1. 5. The gap between the circuit board and the bottom plate of the housing is 5 mm to 2
The electronic device housing according to claim 1, which has a length of 0 mm.