JPS5821900A - Cooler for electronic part - 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 The present invention relates to a cooling device for electronic components mounted on a printed board. - In recent years, with the rapid advancement of integrated circuits and large-scale integrated circuits, the packaging density on printed circuit boards and the packaging density of electronic devices constructed by arranging multiple printed circuit boards in parallel has become higher year by year. ing. Heat generated by electronic components as packaging density increases (1).

The combination of reliability and reliability has become a major problem.

Conventionally, in electronic devices with such a high packaging density, a forced air cooling method has been adopted in which a plurality of printed circuit boards with electronic components mounted thereon are arranged side by side, and the components are cooled by blowing air directly onto them using a fan or the like.

On the other hand, the environments in which electronic devices are placed range from air-conditioned rooms to electrical rooms,
Things are getting worse from the electrical room to the field.

If the above-described forced air cooling method is employed in such a bad environment, dust in the air may adhere to the pins of components such as integrated circuits, causing short circuits. Furthermore, when used in an environment where corrosive gas exists, unexpected accidents have occurred in which the pin portion corrodes due to the corrosive gas, becomes thinner, and eventually disappears.

As a way to solve these problems, research has been conducted into coating agents for printed circuit boards and components mounted on the substrate, and coating agents that are environmentally resistant have also been developed. However, it is not necessarily the best because it has practical drawbacks, such as the inability to replace parts because the coating film is thick and hard.

As described above, in electronic devices used on-site or in an electrical room, the direct forced air cooling method, in which air is directly applied to the surface of components using a fan or the like, is viewed as problematic in terms of reliability.

An indirect cooling method is available to solve the above-mentioned problems in the direct air cooling method. In the indirect cooling method, the printed circuit board is housed in a box made of aluminum or the like, and the box is cooled by blowing air through the box using a fan or the like. However, this indirect cooling method generally has poor cooling efficiency because air with poor thermal conductivity exists inside the box. Another solution is a fanless self-cooling system that dissipates heat without using a fan. This self-cooling method lowers the component mounting density and radiates heat from the component surface by natural convection, but there is a limit to the heat dissipation area of the component.
Particularly in the case of components with large power consumption, the actual situation is that sufficient heat dissipation cannot be achieved. In the natural cooling method, cooling efficiency is poor because the components essentially create air resistance in natural convection and prevent convection, and the air flow due to natural convection does not flow uniformly over each component surface. . In addition, since the natural cooling method does not use a fan, the parts are not exposed to strong wind directly, but the parts are in direct contact with the atmosphere.
Accumulation of dust from the surrounding environment becomes unavoidable.

The present invention has been made in response to the above-mentioned problems, and its purpose is to provide a cooling device for electronic components that can efficiently dissipate heat without causing failure of the electronic components even in a bad environment. .

A feature of the present invention is that a flat gel-like heat transfer medium with good thermal conductivity and elasticity is provided on the opposite surface of the printed board of the heat sink disposed on one or both sides of the printed board on which electronic components are mounted. The gel-like heat transfer medium is made to adhere to at least the heat-generating part of the electronic component, so that the heat generated by the component is efficiently transferred to the heat sink through the gel-like heat transfer medium and radiated. There is a particular thing.

Hereinafter, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 1 to 6.

1 to 6, reference numeral 1 denotes a printed circuit board, with electronic components 2 mounted on the negative side and pins protruding from the other side. ]A is a connecting part of a printed circuit board, and heat sinks 3a and 3b are arranged on both sides of a printed board 1. Heat sink 3a
, 3b are made of an aluminum plate, a copper plate, or the like having good thermal conductivity in order to uniformly conduct heat in the vicinity of a component that generates a large amount of heat to the entire surface of the heat sink plate. Heat sink 3a.

3b is supported by a plurality of tightening screws 8.

4b. The supports 4a, 4b have grooves 5a for guiding and fixing the printed circuit board 1.

It has 5bl. Sabo) 4a and 4b are heat sinks 3a
, 3b and 3b are provided to be used as a guide when inserting the printed circuit board unit 1-PU shown in FIG. 1 into the device. 5a and 5b are heat sinks 3a
, 3b is a gel-like heat transfer medium formed into a flat plate and adhered to the facing surface of the printed circuit board, and has excellent thermal conductivity and is flexible so as not to damage the parts when pressed against them. As the gel-like heat transfer medium 6a, 6'b, for example, rincon gel is used. The gel-like heat transfer media 5a, 5b are for efficiently transmitting the heat of the electronic component 2 mounted on the printed circuit board 1 to the heat sinks 3a, 3b, and are always in close contact with the electronic component 2, as shown in FIG. It is made up of such a thickness. The gel-like heat transfer medium 6b adhesively formed on the heat sink 3b is provided with escape grooves 7 during compressive deformation, as shown in FIG. Reference numeral 9 denotes a front panel which is integrally connected to the printed circuit board 1.

FIG. 6 is a perspective view showing a part of an electronic device constructed by arranging a plurality of printed board units hPU shown in FIG. 1 in parallel.

In the figure, each printed circuit board unit PU has a gap 10
are arranged in parallel with each other, and are configured so that air can flow through this gap 8 as shown by the solid line arrow. The air flow may be by natural convection or by a fan or the like, and in either case, the cooling effect will be further improved.

Since one embodiment of the present invention has the above-described configuration, heat generated from the electronic component 2 is transmitted to the heat sinks 3a and 3b via the gel-like heat transfer media 5a and 6bl. Heat sinks 3a, 31]
The area is several times larger than the total surface area of the components due to the spacing required when mounting the electronic components 2 on the printed circuit board 1. Therefore, heat can be dissipated well.

Furthermore, since the heat sinks 3a and 3b are made of a material with good thermal conductivity, even if there are parts that generate a large amount of heat locally, the temperature distribution can be made uniform over the entire surface. For this reason,
When considering a component that generates a large amount of heat, the heat dissipation area becomes very large isometrically, resulting in an extremely good heat dissipation effect.

In addition, heat radiation from the heat sinks 3a and 3b is done by natural convection from their sides as shown in Figure 6, but compared to the conventional self-cooling system, the heat sink surfaces of the heat sinks 3a and 3b are made smoother. The resistance to air flow is reduced, and under the same conditions, the wind speed and amount of heat dissipated are increased, further improving cooling efficiency.

On the other hand, in the present invention, since the component 2 is not directly exposed to the atmosphere, dust does not accumulate on the component even in bad environments.
Further, the pin portion will not be corroded by corrosive gas.

Furthermore, in the present invention, it is possible to form the gel-like heat transfer medium 6a+6b by adhering it to the heat sinks 3a and 3b, and to mold it in a separate process from that of the printed circuit board. Therefore, compared to, for example, a method in which a printed circuit board is filled with a gel-like heat transfer medium, workability for preventing resin leakage during molding is improved and manufacturing is easier.

As explained above, the present invention radiates heat generated by electronic components to a heat sink through a gel-like heat transfer medium with good thermal conductivity, and since the electronic components are covered with the gel-like heat transfer medium, Even in a bad environment, heat can be efficiently dissipated without causing failure of electronic components.

Note that in the above embodiment, heat sinks are placed on both sides of the printed circuit board, but if there is no problem with corrosive gas, or if the heat generated by the pins is small, heat sinks may be placed only on the component mounting side of the printed circuit board. Of course, a heat sink may be arranged and a gel-like heat transfer medium may be interposed therebetween.

It is obvious that the heat dissipation effect can be further improved by providing cooling fins on the heat dissipation plate.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
Figure 3 is an enlarged view of part B in Figure 2, Figure 4 is a perspective view of the heat sink, Figure 5 is an exploded perspective view of Figure 1, and Figure 6 is an exploded perspective view of Figure 1. FIG. 3 is a perspective view showing an example of a cooling state according to the invention. 1... Printed circuit board, 2... Electronic components, 3... Heat sink, $50 -488-

Claims (1)

[Claims] 1. Electronic components mounted on a printed board, a heat sink disposed on one or both sides of the printed board, and a gel-like conductor with good thermal conductivity formed by adhering to the surface of the heat sink that faces the printed board. the heat sink is arranged so that the gel-like heat transfer medium is in close contact with the electronic component, and the heat generated by the electronic component is transferred to the gel-like heat transfer medium. A cooling device for electronic components, characterized in that heat is transmitted to the heat sink and radiated through the heat sink.