JPH0315832B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] A heat sink head provided with packing is fixed to the tip of the bellows, and a low melting point metal is held by the heat sink head, and the low melting point metal is used for electronic components. By forming the bellows so as to be in contact with the surface, the adhesiveness between the electronic component and the bellows is improved, and the cooling effect is improved.

[Industrial application field]

The present invention relates to a cooling structure for cooling electronic components such as LSI elements mounted on a printed circuit board, and in particular,
The present invention relates to a cooling structure configured to perform cooling by a cooling plate through which a refrigerant is circulated.

In recent years, electronic components such as LSI elements that are widely used in electronic devices have become more densely packaged and faster, and in order to achieve stable operation, it is important to cool these electronic components efficiently. This is a big issue.

Such cooling is economical, and the cooling structure shown in FIG. 3 using a refrigerant that provides a high cooling effect is known.

FIG. 3 is a perspective view showing an outline of the cooling structure.
A cooling plate 3 is provided to overlap the printed circuit board 1 on which a plurality of electronic components 2 are mounted as shown by an arrow F, and a bellows 5 is fitted to the surface of the electronic component 2 at a predetermined location on the cooling plate 3. It is set up so that

Therefore, the tip of the bellows 5 is connected to the electronic component 2.
One opening 1 of the cooling plate 3 is pressed against the surface of the cooling plate 3.
The refrigerant is supplied from the opening 10 in the direction of arrow A and discharged from the other port 10 in the direction of arrow B, so that the refrigerant is circulated and the heat generated by each electronic component 2 is cooled.

In such a cooling structure, in order to improve the cooling efficiency of the electronic components 2, it is necessary to determine how uniformly the surface of each electronic component 2 is on a predetermined surface of the cooling plate 3.
Moreover, it is important that they are tightly attached to each other so that good heat transfer can be achieved.

[Conventional technology]

Conventionally, the structure was as shown in the conventional cross-sectional view of FIG. 4.

As shown in FIG. 4, a bellows 5 having a heat transfer member 14 fixed to one end thereof is fixed by attaching a flange 11 to a predetermined location of the cooling plate 3 using an O-ring 13. By attaching a heat transfer sheet 12 to the board, the heat transfer sheet 12 is configured to be pressed against the surface of the electronic component 2 mounted on the printed circuit board 1.

Therefore, the refrigerant 4 indicated by the arrow A1 that has flown through the one circulation path 3A of the cooling plate 3 is ejected from the nozzle 3B in the direction of the arrow A2, and further flows through the other circulation path 3A.
The electronic component 2 is cooled via the heat transfer member 14 and the heat transfer sheet 12.

Such a bellows 5 is designed to provide a uniform contact pressure to the surface of the electronic component 2 without adversely affecting the electronic component 2,
It is made of a material such as copper or stainless steel with as thin a wall thickness as possible, and is formed into a bellows shape so as to have spring properties.

The heat transfer sheet 12 is made of a soft resin material mixed with metal powder, which is a good heat conductive material, so that the heat transfer member 14 and the surface of the electronic component 2 can absorb the difference in parallelism and come into close contact with each other. It is formed.

[Problem that the invention seeks to solve]

However, since such a heat transfer sheet 12 uses a resin material as a base material so as to obtain flexibility, its thermal conductivity decreases.

Therefore, there was a problem in that heat absorption by the circulating refrigerant 4 was reduced, resulting in a reduction in cooling capacity.

It is conceivable to apply a jelly-like heat transfer paste to the surface of the electronic component 2 without using such a heat transfer sheet 12, but applying it to the surface of each electronic component 2 requires a huge amount of man-hours. In addition, when it becomes necessary to remove the printed circuit board 1 due to a failure or maintenance inspection, the applied heat transfer paste must be removed, and this removal also requires a huge amount of man-hours just like the application. was.

[Means for solving problems]

FIG. 1 is a sectional view of the principle of the present invention.

As shown in FIG. 1, the tip of the bellows 5 has a low melting point metal 6 that is melted by the heat generated by the electronic component 2, a heat sink head 7 that holds the low melting point metal 6, and a heat sink head 7 that holds the low melting point metal 6. fixed,
A packing 8 is provided to prevent the molten low melting point metal 6 from flowing out.

With this configuration, the above-mentioned problems are solved.

[Effect]

That is, a low melting point metal is provided at the tip of the bellows by a heat sink head so that the low melting point metal is melted by the heat generated by the electronic component, and also by packing to prevent the molten low melting point metal from flowing out. It is designed to be contained.

Therefore, since the low melting point metal becomes liquid during operation, it is possible to improve the adhesion between the bellows and electronic components, and to improve the thermal conductivity compared to conventional heat transfer sheets. can be increased.

Furthermore, when the printed circuit board is removed during a stop, the low melting point metal is condensed and becomes solid, so that it can be removed freely and easily.

〔Example〕

The present invention will be explained in detail below with reference to FIG.
FIG. 2 is an explanatory diagram of an embodiment according to the present invention, in which a is a sectional view and b is an enlarged view of the main part. The same reference numerals indicate the same objects throughout the figures.

As shown in FIG.
is secured to the cooling plate 3 by being fixed using an O-ring 13, and the heat sink head 7 is provided with a low melting point metal 6.

Further, a packing 8 is fixedly formed at a portion where the heat sink head 7 comes into contact with the surface of the electronic component 2.

This low melting point metal 6 is made of an alloy such as gallium (Ga), indium (In), tin (Sn), etc., so that it is solid at low temperatures without cooling and becomes liquid at high temperatures with cooling. formed by
It is melted in the range of 40°C to 120°C.

The heat sink head 7 is made of a material with good thermal conductivity, holds the low melting point metal 6, and uses the spring force of the bellows 5 to hold the electronic component 2.
A low melting point metal 6 is pressed onto the surface of the metal.

Therefore, when the electronic component 2 generates heat, the low melting point metal 6
becomes a liquid, and the heat is transferred to the coolant 4 via the heat sink head 7 by convection, and cooling is performed by the circulation of the coolant 4.

In this case, a packing 8 is fixed to the heat sink head 7 to prevent the liquefied low melting point metal 6 from flowing out from the surface of the electronic component 2.

Therefore, when cooled, the low melting point metal 6 becomes liquid, so it has better adhesion to the surface of the electronic component 2 than the heat transfer sheet 12 described above, and has higher thermal conductivity.

The refrigerant 4 is circulated from one circulation path 3A of the cooling plate 3 to the nozzle 3B as shown by the arrow A11, as described above, and from the nozzle 3B to the nozzle 3B as shown by the arrow A12.
This is performed by ejecting the refrigerant 4 as shown in FIG.

Further, since the low melting point metal 6 is solid when not cooled, when the printed circuit board 1 is removed, it is held by the heat sink head 7 and can be easily removed.

Since the volume of such a low melting point metal 6 expands when it is liquefied, in order to absorb this expansion, it is preferable to provide a cavity or to configure it as shown in FIG. 2b.

In b, an extensible member 9 made of rubber or the like is fixed to the outer periphery of the heat sink head 7, so that when the low melting point metal 6 expands, it protrudes in the direction of the arrow H as shown by the dotted line.

With this configuration, pressure due to expansion can be prevented from being applied to the electronic component 2 in the direction of arrow P, and it is possible to prevent adverse effects on the electronic component 2.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a low melting point metal that becomes liquid when cooling and becomes solid when not cooling, it is possible to improve the adhesion between the refrigerant and electronic components during cooling. Furthermore, when cooling is not performed, the printed circuit board can be easily attached and detached.

Therefore, stable pressure contact between the bellows and electronic components can be obtained, and cooling efficiency can be improved.Furthermore, it is easier to attach and detach the printed circuit board to the cooling plate due to obstacles, which has a great practical effect. It is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the principle of the present invention, FIG. 2 is an explanatory diagram of an embodiment according to the present invention, where a is a sectional view, b is an enlarged view of main parts, and FIG. 3 is a perspective view showing an outline of the cooling structure.
FIG. 4 shows a conventional sectional view. In the figure, 1 is a printed circuit board, 2 is an electronic component, 3 is a cooling plate, 4 is a refrigerant, 5 is a bellows, 6 is a low melting point metal, 7 is a heat sink head, and 8 is a packing.

Claims (1)

[Claims] 1. A cooling plate 3 through which a refrigerant 4 is circulated, a flexible bellows 5 secured to a predetermined position of the cooling plate 3, and an electronic component 2 mounted on a printed circuit board 1. A cooling structure in which the tip of the bellows 5 and the surface of the electronic component 2 are pressed together, and the tip includes a low melting point metal 6 that is melted by heat generated by the electronic component 2; A cooling structure comprising: a heat sink head 7 for holding a low melting point metal 6; and a packing 8 fixed to the heat sink head 7 to prevent the melted low melting point metal 6 from flowing out.