JP2006229102A - Boiling cooler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boiling cooler in which heat radiation performance of a heat radiator can be prevented from being reduced, by suppressing a refrigerant from being stagnant inside a refrigerant channel even in a side heat attitude. <P>SOLUTION: A boiling cooler 1 comprises of a first refrigerant tub 4 to which a heating element 7 is attached; a second refrigerant tub 5 for forming a refrigerant circulation, and a heat radiator comprised of a plurality of flat tubes 3 communicating both the refrigerant tubs and a heat radiating fin 2 interposed between the flat tubes and in which the refrigerant of a predetermined quantity is sealed. In such a boiling cooler 1, each of the flat tubes is disposed between both the refrigerant tubs so that a lengthwise plane LP of the flat tube is inclined at a predetermined angle θ relative to a horizontal plane HP. In such a case, a tube axial center of the flat tube is horizontal. Thus, a refrigerant condensate can be suppressed from being stagnant inside the flat tubes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a boiling cooling device that cools a heating element by transferring boiling heat of a refrigerant, and is particularly suitable for a cooling device for an electronic device such as a computer chip (CPU).

  2. Description of the Related Art In recent years, heat generation elements such as CPUs have increased in calorific value, and the need for a high-performance cooling device using a refrigerant is increasing in order to keep the temperature of the elements optimal. In order to ensure the freedom of housing design, the cooling device can be used for both bottom heat (heating element is in close contact with the bottom surface of the cooling device) and side heat (with heating element in close contact with the bottom surface of the cooling device and rotating 90 degrees). Design is indispensable, and from the aspect of reducing the number of parts and effective use of the heat dissipation unit, a cooling device having a structure in which a refrigerant flow path is vertically formed from a refrigerant tank to which a heating element is attached has been proposed so far. (For example, see Patent Document 1)

  However, in this conventional cooling device, the refrigerant flow path of the heat radiating portion is horizontal with respect to the direction of gravity during the side heat posture. Here, since a flat tube is used for the refrigerant flow path, the refrigerant stays in the flow path and closes the flow path, resulting in poor circulation of the refrigerant, resulting in unstable heat dissipation performance or insufficient refrigerant. Sometimes.

  In order to solve such a problem of the clogging of the refrigerant flow path by the refrigerant, as shown in Patent Document 2, the tube is arranged so as to have a height difference between both ends of the tube connected between the two headers. Those arranged between the headers are known.

  However, since the cooling device disclosed in Patent Document 2 is inclined along the axial direction of the tube, there is a problem that a large wasted space is generated and the size of the device cannot be avoided. Further, the cost increases due to an increase in the number of parts.

JP 2003-28584 A JP 2002-206880 A

  The present invention has been made in view of the above problems, and its purpose is to allow common use of bottom heat and side heat, and to retain the refrigerant in the refrigerant flow path even in the side heat posture. Is to provide a boiling cooling device that can suppress the deterioration of the heat dissipation performance of the heat dissipation portion.

The present invention provides a boiling cooling device according to each of the claims as means for solving the problems.
The boiling cooling device according to claim 1 is interposed between each refrigerant flow path and a plurality of refrigerant flow paths 3 communicating between the first refrigerant tank 4, the second refrigerant tank 5, and both the refrigerant tanks 4 and 5. The heat radiation part is composed of a heat radiation fin 2 and a predetermined amount of refrigerant is sealed therein, the refrigerant flow path 3 is the flat tube 3, and the longitudinal surface LP of the flat tube is horizontal HP. The flat tube is arranged so as to be inclined at a predetermined angle θ, so that the amount of refrigerant staying in the flat tube (refrigerant flow path) 3 can be reduced even in the side heat posture. The flat tube is not blocked by the refrigerant, and the heat dissipation performance of the heat dissipation portion can be stably maintained.

In the boiling cooling device according to the second aspect, the radiating fin is a corrugated fin, and the corrugated fin is also inclined at a predetermined angle like the flat tube. In other words, a heat radiating portion formed by alternately stacking flat tubes and corrugated fins is disposed between both refrigerant tanks so that the longitudinal surface of the flat tubes is inclined at a predetermined angle θ with respect to the horizontal.
According to the third aspect of the present invention, since the flat plane LP of the flat tube 3 is inclined at a predetermined angle with respect to the horizontal plane HP, the boiling cooling device is arranged so that the surface on which the heating element is attached is the side surface. Even in the side heat posture, it is possible to prevent the flat tube from being blocked by the liquid refrigerant.
Further, the temperature of the cooling medium is increased as it becomes downstream in the flow direction of the cooling medium by exchanging heat with the refrigerant. According to the fourth aspect of the present invention, the flat tube is inclined so that the upstream side in the flow direction of the external fluid is upward, so that the portion through which the gas refrigerant passes in the flat tube and the low-temperature external fluid are heated. Can be exchanged.

  Hereinafter, a boiling cooling apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a boiling cooling apparatus according to an embodiment of the present invention, and FIG. 2 illustrates a comparison between (a) the present invention and (b) the prior art in the AA cross section of FIG. 3A is a perspective view of the refrigerant passage of the present invention, and FIG. 3B is a perspective view of the refrigerant passage of the prior art. The boiling cooling device 1 cools the heating element 7 by the boiling heat transfer of the refrigerant, and includes a pair of refrigerant tanks 4 and 5 and a heat radiating portion, and is manufactured by integral brazing. The heating element 7 is mainly an electronic device such as a computer chip (CPU), and is attached in close contact with the substantially central portion of the outer wall surface of the first refrigerant tank 4 on the heat receiving side. The boiling cooling device 1 of the present invention is suitable for use in a side heat posture as shown in FIG. 1, but the bottom heat of the first refrigerant tank 4 on the heat receiving side is on the lower side. Naturally it can also be used in posture.

  The boiling cooling device 1 is interposed between the first refrigerant tank 4 on the heat receiving side to which the heating element 7 is attached, the second refrigerant tank 5 that forms the refrigerant circulation, and the first and second refrigerant tanks 4 and 5. And a heat-radiating part that forms a kind of hermetically sealed container in which a predetermined amount of refrigerant is sealed, and forms a refrigerant circulation system in which vaporization and condensation of the refrigerant are repeated. Yes.

The heat radiating portion includes a plurality of refrigerant flow paths 3 communicating between the first and second refrigerant tanks 4 and 5, and heat radiating fins 2 interposed between the refrigerant flow paths 3 to increase the heat radiation area, In order to protect this fin 2, it is comprised from the fin holding member 6 provided in the both sides of a thermal radiation part. In FIG. 1, the radiation fins 2 are corrugated fins (corrugated fins), but are not limited thereto. Reference numeral 8 denotes a capillary member provided on the heat receiving side inside the first refrigerant tank 4.
These members (refrigerant tanks 4 and 5, refrigerant flow path 3, radiating fins 2, and fin restraining members 6) constituting the boiling cooling device 1 are preferably metal materials (for example, copper, aluminum, etc.) having excellent heat conductivity. It is formed by.

  Next, features of the present invention will be described. In the present invention, each refrigerant flow path 3 is composed of a flat tube 3. In the prior art, as shown in FIGS. 2 (b) and 3 (b), the refrigerant flow path (flat tube) 3 has both refrigerant tanks 4, 5 so that the longitudinal direction surface of the flat tube 3 is horizontal. In this case, there is a possibility that the refrigerant stays in the flat tube 3 and closes the flat tube 3 due to the surface tension. In the present invention, however, FIG. ) And FIG. 3A, the flat tube 3 is formed between the refrigerant tanks 4 and 5 so that the longitudinal surface (flat surface) LP of the flat tube 3 is inclined at a predetermined angle θ with respect to the horizontal HP. The tube axis C is disposed horizontally. The flat tube 3 is inclined so that the upstream side in the flow direction of the external fluid (cooling air) that exchanges heat with the refrigerant is upward. When the fin 2 is a corrugated fin, the fin 2 is also inclined by a predetermined angle θ along the inclination angle θ of the flat tube 3. In this way, the heat radiating portion composed of the flat tubes 3 and the fins 2 is installed at a predetermined angle θ along the flow direction of the external fluid.

  In this way, by arranging the flat tube 3 at an angle, the place where the refrigerant condensate is held is only at the bottom surface of one corner, so if the condensate stays to some extent, it flows down from both sides of the flat tube 3, The amount of the refrigerant condensate staying in the flat tube 3 can be reduced, and the flat tube 3 is not blocked.

The operation of the boiling cooling device 1 having the above configuration will be described.
A predetermined amount of refrigerant enclosed in the boiling cooling device 1 receives heat from the heating element 7 in the first refrigerant tank 4, boils and vaporizes, and flows into the flat tube (refrigerant flow path) 3. As the external fluid passes from the right side to the left side in FIG. 2 (a) through the heat radiating section, the boiling vaporized refrigerant vapor transfers heat to the flat tube 3 → radiation fin 2 → external fluid and dissipates heat. It condenses and liquefies, makes a U-turn from the second refrigerant tank 5 and returns to the first refrigerant tank 4.

  In the present embodiment, the flat tube 3 is disposed between the refrigerant tanks 4 and 5 so that the tube axis C of the flat tube 3 is kept horizontal while the longitudinal surface LP is inclined with respect to the horizontal HP. Therefore, the refrigerant condensate is suppressed from staying in the flat tube 3, the flat tube 3 can be prevented from being blocked, and stable heat dissipation performance can be maintained. In particular, since the flat tube 3 is inclined so that the upstream side in the flow direction of the external fluid is upward, the portion through which the gas refrigerant passes inside the flat tube 3 and the low-temperature external fluid can be heat-exchanged.

  In addition, the boiling cooling device 1 of this embodiment can be used also in the bottom heat attitude | position. The concept of the present invention can also be applied to other heat exchangers other than the boiling cooling device.

It is sectional drawing of the boiling cooling device in embodiment of this invention. 2A is a cross-sectional view taken along the line AA of FIG. 1 in the embodiment of the present invention, and FIG. 2B is a cross-sectional view of a boil cooling device in the prior art. FIG. 3A is a perspective view of the refrigerant passage in the embodiment of the present invention, and FIG. 3B is a perspective view of the refrigerant passage in the prior art.

Explanation of symbols

1 Boiling cooler 2 Heat transfer fin 3 Refrigerant passage (flat tube)
4, 5 Refrigerant tank 6 Fin restraining member 7 Heat generating element LP Longitudinal plane HP Horizontal θ Predetermined angle C Tube axis

Claims (4)

A first refrigerant tank (4) to which a heating element (7) is attached;
A second refrigerant tank (5) forming a refrigerant circulation;
A heat transfer section comprising a plurality of refrigerant flow paths (3) communicating between the refrigerant tanks (4, 5), and heat radiation fins (2) interposed between the refrigerant flow paths;
In the boiling cooling device (1) in which a predetermined amount of refrigerant is sealed inside,
The boiling cooling device, wherein the refrigerant flow path (3) is a flat tube, and the flat tube is disposed with a longitudinal plane LP of the flat tube inclined at a predetermined angle θ with respect to a horizontal HP.   The said cooling fin (2) is a corrugated fin, Comprising: The said corrugated fin is also arrange | positioned by the predetermined angle (theta) similarly to the said flat tube, The boiling cooling device of Claim 1 characterized by the above-mentioned. A first refrigerant tank (4) in which a heating element (7) is mounted and a refrigerant is enclosed therein, and a second refrigerant tank (5) disposed on the side opposite to the heating element of the first refrigerant tank (4) ) And a plurality of flat tubes (3) that are stacked and communicate with the first refrigerant tank (4) and the second refrigerant tank (5),
In the boiling cooling device that cools the heating element (7) by exchanging heat with an external fluid and condensing and liquefying the refrigerant that has evaporated and boiled by the heat of the heating element (7),
The boiling cooling device characterized in that the flat surface LP of the flat tube (3) is inclined at a predetermined angle with respect to the horizontal surface HP.   The boiling cooling device according to claim 3, wherein the flat tube is inclined so that the upstream side in the flow direction of the external fluid is upward.

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