JP2010199371A - Heat sink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forced air-cooled heat sink which can reduce the load on an air-exchange means, such as, fan and which can be manufactured at low cost. <P>SOLUTION: In an interdigital heat sink, a plurality of planar fins are arranged into an interdigital shape, in a planar base plate 11. A part of the fins is a fixed fin 12, which is fixed to the base plate, and another part of the fins, is a movable fin 13. The fixed fin 12 and the movable fin 13 are connected by a bimetal 14. While a chip is at a relatively low temperature, the movable fin 13 is moved to the vicinity of the fixed fin, to avoid load on an air exchange means. Meanwhile, at a high temperature, the movable fin 13 is moved to the vicinity of a center between the fixed fins 12 and the movable fin 13, and the fin is set in a state with narrowed air circulation path and enhanced the heat dissipation efficiency. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a heat sink for the purpose of efficiently cooling electronic parts having a high calorific value.

When a semiconductor element for an electronic computer represented by a CPU (hereinafter referred to as a chip) is used, it is necessary to take measures against heat according to the amount of heat generated. There are various ways of heat dissipation, such as those using the Peltier effect and combinations of heat pipes, but all of them finally dissipate heat to cooling fluids such as air and water. And liquid cooling. The air-cooling type uses a metal (aluminum or copper) having excellent thermal conductivity and radiates heat into the air through fins formed in a shape that increases the contact area with the surrounding air. In the liquid cooling method, heat is radiated to the liquid flowing in a pipe or the like installed at a position very close to the heating element. The latter has a higher cooling capacity than the former, but the former is generally selected as much as possible because it is expensive and requires labor for maintenance.
Among air-cooled types, the air around the heat sink is exchanged by free convection heat transfer (hereinafter referred to as natural air cooling), which is left to natural convection, and forced convection heat transfer (hereinafter, forced air cooling) that is forcibly switched by a fan or the like. The latter has a higher heat dissipation performance.
In the case of forced air cooling, the air exchange means such as fans reduce the load when there are few obstacles around the air circulation around the air. growing. If it continues to be used in a state where the load is large, the life of the air exchange means such as a fan will be shortened.
For example, as long as the chip is not too hot immediately after power is turned on and heat dissipation from the heat sink is not necessary, air exchange means by adjusting the number and orientation of the fins of the heat sink itself, which becomes an obstacle to air circulation If the load is applied to the air exchange means when the chip gets hot, the life of the air exchange means such as a fan can be extended.
Patent Document 1 describes a technique in which a movable fin is provided on the exhaust port side of the heat sink and the angle thereof is adjusted in order to adjust the air volume guided to the heat sink.
However, although the movable fin of Patent Document 1 is controlled by a control mechanism and is considered to be suitable for applications such as the high-temperature test apparatus of Patent Document 1, it is used in actual products such as electronic computers. It is desirable that such a heat sink can be manufactured at a low cost with a simpler mechanism.

Japanese Patent No. 3339484

The present invention has been made in view of the above problems, and an object of the present invention is to provide a forced air-cooling heat sink that can reduce the load of air exchange means such as a fan and can be manufactured at low cost.

In order to solve the above problem, in claim 1 of the present invention,
A comb heat sink in which a plurality of flat fins are arranged in a comb shape on one of the main surfaces of a flat base plate,
A part of the flat fins is a fixed fin fixed to the base plate,
Another part of the flat fins is a movable fin,
A heat sink, wherein the fixed fin and the movable fin are connected via a connection plate that changes a distance between the fixed fin and the movable fin according to temperature;
It is what. In addition, as such a connection plate, a thin plate of bimetal or shape memory alloy can be used.

According to the heat sink of the present invention, while the chip is not yet very hot, and the entire heat sink and the connection plate are relatively cold, moving the movable fins in the vicinity of the fixed fins reduces the air circulation path. It can be made wide so that the air exchange means is not so heavily loaded. For this reason, the noise is also small.
Also, if the chip becomes hot and therefore the heat sink and the connection plate become hot, moving the movable fins near the center between the fixed fins narrows the air circulation path and places a load on the air exchange means. The heat dissipation efficiency can be increased.

The schematic diagram which shows the state of comparatively low temperature in the 1st Embodiment of this invention The schematic diagram which shows the state of high temperature in the 1st Embodiment of this invention Schematic diagram showing a relatively low temperature state in the second embodiment of the present invention The schematic diagram which shows a high temperature state in the 2nd Embodiment of this invention.

Hereinafter, embodiments of the heat sink of the present invention will be described.
1 and 2 are schematic views showing an example of the first embodiment of the heat sink of the present invention. FIG. 1 shows a state where the heat sink is at a relatively low temperature. FIG. 1 (A) is a top view and FIG. 1 (B) is a side view. FIG. 2 shows a state when the heat sink becomes hot. FIG. 2 (A) is a top view and FIG. 2 (B) is a side view.
In the heat sink 10 of this embodiment, a plurality of fixed fins 12 are integrally formed on one surface of a base plate 11 in the same manner as a normal comb heat sink, and the fixed fins 12 are movable via a connection plate 14. Fins 13 are connected.
In order to improve the air circulation efficiency, it is desirable to arrange the fixed fins 12 and the movable fins 13 so as to be substantially parallel to each other. Therefore, it is desirable that there are two or more connecting plates 14 for connecting the fixed fins 12 and the movable fins 13 per group.
The movable fins 13 have a rectangular plate shape similar to that of the fixed fins 12 and are arranged with their side surfaces in contact with the surface of the base plate 11. This is for transferring heat to the movable fins 13 well.
The connection plate 14 is a thin plate made of a bimetal or a shape memory alloy. One end of the connection plate 14 is fixed to the fixed fin 12 and the other end is fixed to the movable fin 13 in a bent state. When the heat sink 10 is at a relatively low temperature, the movable fin 13 is held at a position close to the fixed fin 12 while being bent strongly as shown in FIG.
On the other hand, when the heat sink 10 reaches a high temperature, as shown in FIG. 2, the connection plate 14 is opened, and the movable fin 13 is held at a position far from the fixed fin 12. At this time, it is desirable to adjust the length of the connecting plate 14 and the degree of opening so that the movable fin 13 comes to substantially the center between the adjacent fixed fins.
1 and 2, the connection plate 14 is shown as being bent with a crease, but a connection with a crease may also be used. Moreover, although the case where the connection plate 14 is folded inside the heat sink 10 is shown, it may be outside the heat sink 10 if there is a margin around the installation space.
1 and 2 show the case where the connection plate 14 is attached to the end of the fin on the side surface of each fin of the heat sink 10, but the upper surface of each fin of the heat sink 10 is the end of the hook. It may be attached to the part.
3 and 4 are schematic views showing an example of the second embodiment of the heat sink of the present invention. FIG. 3 shows a state where the heat sink is at a relatively low temperature. FIG. 3 (A) is a top view and FIG. 3 (B) is a side view. FIG. 4 shows a state when the heat sink becomes hot. FIG. 4 (A) is a top view and FIG. 4 (B) is a side view.
Each of the movable fins 13 is connected to a common overall connection plate 18 by an individual connection plate 17. The end of the overall connection plate 18 is connected to the movable connection plate 15, and the movable connection plate 15 is further connected to a predetermined fixed fin 12 a by a fixed connection plate 16. The movable connection plate 15 is made of a stretchable elastic body such as a spring or rubber. On the other hand, the individual connection plate 17, the overall connection plate 18, and the fixed connection plate 16 are rigid materials that are substantially non-stretchable. It is composed of
And the fixed fin 12a to which the fixed connection plate 16 is connected is connected to a predetermined movable fin 13 via a connection plate 14 made of bimetal. As the connection plate 14, as described above, a shape memory alloy or the like can be used in addition to the bimetal.
In this embodiment, when the heat sink 10 is at a relatively low temperature, the connection plate 14 is strongly bent as shown in FIG. For this reason, the movable fin 13 connected to the fixed fin 12 a is held at a position close to the fixed fin 12.
On the other hand, when the heat sink 10 reaches a high temperature, as shown in FIG. 4, the connection plate 14 is opened, and the movable fin 13 connected to the fixed fin 12 a is moved to a position far from the fixed fin 12.

  The movable fins 13 are connected to the common overall connection plate 18 by the individual connection plates 17, and the other movable fins 13 are also connected to the common overall connection plate 18, so that they are connected to the fixed fins 12a. As the movable fins 13 move, all the movable fins 13 move to positions far from the fixed fins 12a. At this time, since the movable connecting plate 15 expands and contracts, the movable fin 13 can move smoothly without applying an excessive force.

DESCRIPTION OF SYMBOLS 10 Comb-shaped heat sink 11 Comb-shaped heat sink base plates 12, 12a Fixed fin 13 for comb-shaped heat sink 13 Movable fin 14 Connection plate 15 Movable connection plate 16 Individual connection plate 18 Overall connection plate

Claims (1)

A comb heat sink in which a plurality of flat fins are arranged in a comb shape on one of the main surfaces of a flat base plate,
A part of the flat fins is a fixed fin fixed to the base plate,
Another part of the flat fins is a movable fin,
The heat sink, wherein the fixed fin and the movable fin are connected via a connection plate that changes a distance between them according to temperature.

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