WO2011145618A1

WO2011145618A1 - Ebullient cooling device

Info

Publication number: WO2011145618A1
Application number: PCT/JP2011/061320
Authority: WO
Inventors: 有仁松永; 吉川　実; 坂本　仁
Original assignee: 日本電気株式会社
Priority date: 2010-05-19
Filing date: 2011-05-17
Publication date: 2011-11-24
Also published as: CN102869943A; JPWO2011145618A1; US20130056178A1

Abstract

Disclosed is an ebullient cooling device which comprises a chamber, a heat sink, a heat receiving member, and a heat release member. The chamber comprises a heat transfer plate and an airtight space. A heating element is disposed on the outer surface of the heat transfer plate, and the airtight space is formed inside the heat transfer plate and is filled with a refrigerant, the phase of which changes between a liquid and a gas. The heat sink is disposed on the outer surface of the heat transfer plate. The heat receiving member is disposed on the inner surface of the heat transfer plate in a manner such that the heat receiving member faces the heating element with the heat transfer plate therebetween, and the heat receiving member transfers heat generated by the heating element to the refrigerant. The heat release member is disposed on the inner surface of the heat transfer plate and receives heat transferred from the refrigerant to release the heat to the heat sink. The heat receiving member and the heat release member are spaced apart from each other in the surface direction of the heat transfer plate. The heat receiving member is immersed in the liquid refrigerant.

Description

Boiling cooler

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiling cooler that suppresses heat generation of an LSI or IC by utilizing a phase change phenomenon of a refrigerant such as boiling or liquefaction, particularly in an electronic device equipped with an LSI or IC.

LSIs and ICs used in electronic devices such as computers are acceleratingly increasing with each generation. Furthermore, in recent years, there has been an increasing demand for smaller and thinner devices. For this reason, the heat generation density of LSI and IC tends to increase further in the future. In order to operate these LSIs and ICs stably at high speed, it is necessary to control the operating temperature below a certain temperature. A cooling method is employed in accordance with the heat generation amount of these LSIs and ICs. However, when a device is reduced in size and thickness, a cooler such as a heat sink mounted on an LSI or IC cannot secure a size corresponding to the amount of heat generated.

Therefore, a boiling cooler including a heat receiving plate 3, a heat transfer means 4, and a heat sink 5 as shown in FIG. 11 has been proposed. The small heat receiving plate 3 is disposed on a heating element 2 such as an LSI or an IC installed on the substrate 1 and absorbs heat from the heating element 2. The heat absorbed by the heat receiving plate 3 is transported via the heat transfer means 4 to the heat sink 5 mounted on the board 1 wider than the heating element 2.

As the heat transfer means 4, a metal having high thermal conductivity such as aluminum or copper may be used. However, it is preferable to use the heat pipe 6 having better heat transfer performance as the heat transfer means 4. The heat pipe 6 utilizes a phase change phenomenon in which the refrigerant is vaporized by the heat receiving plate 3 in contact with the heating element 2, and the vaporized refrigerant is liquefied by the heat radiating plate 7 provided below the heat sink 5. The heat pipe 6 uses this phase change phenomenon to transfer heat generated in the heating element 2 such as an LSI or an IC to the heat sink 5.

The structure of the heat pipe 6 will be described with reference to a schematic sectional view of FIG. The heat pipe 6 includes a hollow tubular container 8 made of a metal having high thermal conductivity such as aluminum and copper, and a refrigerant sealed in the container 8. One end of the heat pipe 6 is connected to a heat receiving plate 3 that is in contact with the heating element 2 such as an LSI or an IC. A heat radiating plate 7 in contact with the heat sink 5 serving as a cooler is connected to the other end of the heat pipe 6.

In the heat receiving plate 3, the refrigerant changes phase from liquid to gas, while in the heat sink 7, the refrigerant changes phase from gas to liquid. For this reason, in such a heat pipe 6, the pressure on the heat receiving plate 3 side becomes high, and the vaporized refrigerant generated in the heat receiving plate 3 moves to the heat radiating plate 7 side. Further, the liquid refrigerant generated on the heat radiating plate 7 side returns to the heat receiving plate 3 by passing through a fine mesh called a wick 9 attached to the inner surface of the heat pipe 6. The mesh gap is very narrow. By utilizing the surface tension of the liquid refrigerant, the refrigerant passes through the mesh gap and is returned to the heat receiving plate 3 side. By repeating these phenomena, heat transport by the heat pipe 6 is enabled. By utilizing the phase change of the refrigerant in this way, the heat pipe 6 can realize much higher heat conduction than metals such as aluminum and copper having high heat conductivity.

However, in the heat pipe 6, when the liquefied refrigerant generated in the heat radiating plate 7 is returned to the heat receiving plate 3, the heat pipe 6 passes through the fine mesh-like wick 9, so that the heat transport amount cannot be increased. Therefore, it is difficult to cool the heating element 2 having a large amount of heat.

For this reason, Patent Document 1 proposes a boiling cooler in which a refrigerant is boiled by a heat receiving plate, and a liquid generated by the heat radiating plate is refluxed by gravity. This heat transport using boiling is characterized by a large heat transport capability because it uses more refrigerant than the heat pipe and recirculates by gravity. In patent document 1, the loop-shaped flow path is formed in the flat plate. With this configuration, the flow path through which the gaseous refrigerant passes and the liquid refrigerant generated in the heat radiating plate recirculate, so that the flow path is separated, reducing pressure loss due to collision between the two and increasing the equivalent thermal conductivity.

In Patent Document 2, the area where the heat receiving plate comes into contact with the refrigerant is increased by placing a boiling promoting structure on the heat receiving plate, the boiling is promoted by improving the heat transfer coefficient transmitted from the heat generating part to the refrigerant, and the equivalent thermal conductivity. Is increasing.

In Patent Document 3, the heat radiation wall is provided with a fin having a notch partially, and the equivalent thermal conductivity is increased by increasing the surface area for condensation and enhancing the condensation effect.

Patent Document 4 shows a configuration in which corrugated fins having low heights are arranged in two stages (or three or more stages), and the corrugated fins are joined with their positions aligned so that heat can be transferred to each other. Has been.

In Patent Document 5, chevron-shaped first fins are arranged on the inner sides of the heat receiving plate and the heat radiating plate, respectively, and chevron-shaped second fins are arranged on the inner side of the first fins through a support member such as a wire mesh. The configuration shown is shown.

Japanese Unexamined Patent Publication No. 2006-344636 Japanese Unexamined Patent Publication No. 07-161888 Japanese Unexamined Patent Publication No. 2000-74536 Japanese Unexamined Patent Publication No. 01-209356 Japanese Unexamined Patent Publication No. 11-31768

However, as shown in Patent Document 1, if a structure in which the flow path of the boiling cooling gas and the liquid refrigerant is divided as a method for improving the equivalent thermal conductivity of the flat plate boiling cooler, the flat cooling plate using boiling cooling is adopted. There is a problem that the design becomes complicated. That is, if it is going to divide a flow path, it will be necessary to adjust a flow path finely for every apparatus, and versatility will be impaired.

In addition, as shown in Patent Documents 2 to 5, in the method of increasing the area in contact with the refrigerant through the fins on the heat receiving plate or the heat radiating plate, the region where boiling condensation occurs is increased only by increasing the area. Cannot be expected, and a large improvement in equivalent thermal conductivity cannot be expected.
Further, in the techniques disclosed in Patent Documents 2 to 5, the fins (heat receiving member, heat radiating member) installed on the heat receiving plate and the heat radiating plate are in a positional relationship where they interfere with each other. As a result, there is a problem that the efficiency of boiling and condensing of the refrigerant is lowered.

This invention was made in view of the above-mentioned circumstances. An example of the object of the present invention is to provide a boiling cooler that can efficiently dissipate heat with a simple configuration and can be applied to LSIs and ICs that generate large amounts of heat.

In order to solve the above problems, the boiling cooler of the present invention includes a chamber, a heat sink, a heat receiving member, and a heat radiating member. The chamber includes a heat conduction plate in which a heating element is provided on the outer surface, and a sealed space that is provided inside the heat conduction plate and is filled with a refrigerant that changes phase between liquid and gas. The heat sink is provided on the outer surface of the heat conducting plate. The heat receiving member is provided on an inner surface of the heat conducting plate so as to face the heat generating member with the heat conducting plate interposed therebetween, and transmits heat generated by the heat generating member to the refrigerant. The heat dissipating member is provided on the inner surface of the heat conducting plate, receives heat transferred by the refrigerant, and dissipates heat to the heat sink. The heat receiving member and the heat radiating member are spaced apart from each other in the surface direction of the heat conducting plate. The heat receiving member is immersed in the liquid coolant.

According to the present invention, the heat generated in the heating element is transported to the heat sink by changing the phase of the refrigerant sealed in the sealed space of the chamber to a liquid / gas between the heat receiving member and the heat radiating member gas. Can do. Further, the heat receiving member and the heat radiating member are disposed apart from each other in the surface direction of the heat conducting plate. That is, the heat receiving member and the heat radiating member are disposed in a positional relationship that does not face each other. Therefore, the movement of the refrigerant that is a gas in the heat receiving member is not hindered, and the heat conduction efficiency can be maintained high. Therefore, it is possible to efficiently dissipate heat with a simple configuration, and it is possible to deal with LSIs and ICs that generate a large amount of heat.

It is a disassembled perspective view of the boiling cooler concerning a 1st embodiment of the present invention. It is the disassembled perspective view which looked at the boiling cooler shown in FIG. 1 from the back side. It is a longitudinal cross-sectional view of the boiling cooler which concerns on 1st Embodiment of this invention. It is a disassembled perspective view of the boiling cooler which concerns on 2nd Embodiment of this invention. It is a disassembled perspective view of the boiling cooler which concerns on 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the boiling cooler which concerns on 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the boiling cooler which concerns on 5th Embodiment of this invention. It is a perspective view of the boiling cooler concerning a 6th embodiment of the present invention. It is a longitudinal cross-sectional view of the boiling cooler which concerns on 6th Embodiment of this invention. It is a permeation | transmission front view explaining the flow of the refrigerant | coolant in the boiling cooler which concerns on 6th Embodiment of this invention. It is a perspective view of the conventional boiling cooler. It is a cutaway view showing the internal structure of the heat pipe.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
1 to 3 show a boiling cooler 20 according to a first embodiment of the present invention. For example, a heating element 10 such as an LSI or an IC is joined to the boiling cooler 20. More specifically, the heating element 10 is joined to the heat receiving plate 22 of the boiling cooler 20 with a heat conductive grease or a heat conductive sheet. At this time, the heating element 10 may be welded with solder.

The boiling cooler 20 has a hollow chamber 24 having a flat plate shape. The chamber 24 includes a side wall portion 21 formed in a rectangular frame shape, a heat receiving plate (heat conducting plate) 22 covering the upper opening 21A of the side wall portion 21, and a heat radiating plate (heat conducting plate) covering the lower opening 21B of the side wall portion 21. Plate) 23.

The heat receiving plate 22 and the heat radiating plate 23 are made of metal such as copper or aluminum having high thermal conductivity. The heat receiving plate 22 and the heat radiating plate 23 are arranged to face each other in the thickness direction of the chamber 24. The upper opening 21 </ b> A and the lower opening 21 </ b> B of the side wall 21 are closed by the heat receiving plate 22 and the heat radiating plate 23, thereby forming a sealed space inside the side wall 21. This sealed space is filled with the refrigerant C. As the refrigerant C, a liquid refrigerant C1 and a gas refrigerant C2 coexist in the sealed space. The refrigerant C can be phase-changed into liquid / gas.

The side wall 21 of the chamber 24 is provided with a refrigerant inlet 21C for injecting the refrigerant C into the sealed space.
The chamber 24 may be formed by separately manufacturing the side wall portion 21, the heat receiving plate 22, and the heat radiating plate 23 and then bonding them by brazing or the like. Alternatively, the chamber 24 may be formed by integrally molding either the heat receiving plate 22 or the heat radiating plate 23 with the side wall portion 21. The O-ring 25 may be disposed around the upper opening 21A and the lower opening 21B of the side wall portion 21. The upper opening 21A and the lower opening 21B may be blocked by the heat radiating plate 23 and the heat receiving plate 22 via the O-ring 25, and the heat radiating plate 23 and the heat receiving plate 22 may be attached to the side wall portion 21 with screws or the like. Thus, when the O-ring 25 is used, the heat receiving plate 22 and the heat radiating plate 23 can be easily detached. As a result, it is possible to improve workability when mounting a heating element 22 and a heat sink 28 described later.

On the outer surface of the sealed space of the heat receiving plate 22, a heating element 10 such as an LSI or an IC serving as a heat source is disposed. A heat receiving member 26 is fixed to the inner surface of the heat receiving plate 22 where the heating element 10 is disposed. The heat receiving member 26 transmits the heat generated in the heating element 10 to the refrigerant C.

The heat receiving member 26 includes a plurality of fins arranged and fixed on the inner surface of the heat receiving plate 22 at regular intervals. The plurality of fins (in this embodiment, pin fins) are rectangular parallelepiped rectangular fins or pin fins whose surface is roughened to promote boiling.

When a plurality of heating elements 10 are installed on the outer surface of the heat receiving plate 22, the heat receiving member 26 is disposed at a location that matches the heating element 10 or in the vicinity thereof. The heat receiving member 26 is desirably integrally formed with the heat receiving plate 22 by cutting, forging or the like in order to reduce the thermal resistance. On the other hand, from the viewpoint of productivity, it is preferable to separately produce a plurality of fins constituting the heat receiving member 26 and braze them to the heat sink 23.

In the heat receiving member 26 made of pin fins, a plurality of pin fins are arranged in a matrix so as not to inhibit the flow of the vaporized refrigerant C1 and the refrigerant C2 liquefied and refluxed as much as possible. It is preferable to secure the gap between the pin fins from 1 mm to several mm so that the heat receiving member 26 does not disturb the separation of bubbles generated at the time of boiling. In the case of using rectangular fins made of a rectangular parallelepiped member, it is conceivable to install more fins by reducing the thickness from the viewpoint of increasing the surface area. On the other hand, if the fins are thin, the heat capacity of the fins is small, which is not preferable from the viewpoint of cooling efficiency. Furthermore, when the fin is thin, processing becomes difficult. Therefore, it is desirable that at least the fin has a thickness of 1 mm to several mm.

The height of the fin, that is, the height from the inner surface of the heat receiving plate 22 in the heat receiving member 26 is the thickness of the chamber 24, that is, the facing distance between the heat receiving plate 22 and the heat radiating plate 23 (the heat receiving plate 22 and the heat radiating plate 23. It is preferable to set the dimension to approximately one half of the distance between the two. This is because the entire heat receiving member 26 is immersed in the liquid refrigerant C1 and the entire surface of the fin is utilized for boiling.

It is preferable that each fin of the heat receiving member 26 has been subjected to a surface roughening process having a surface roughness in the range of 1 μm to 100 μm. Thereby, many acute-angled shapes used as the nucleus when a bubble generate | occur | produces by the heat receiving of the refrigerant | coolant C1 can be formed in the surface of the heat receiving member 26. FIG. As a result, boiling of the liquid refrigerant C on the surface of the heat receiving member 26 can be promoted.

Inside the heat radiating plate 23, a heat radiating member 27 for removing heat from the vaporized refrigerant C2 is provided. The heat radiating member 27 is disposed away from the heat receiving member 26 in the surface direction of the heat receiving plate 22 and the heat radiating plate 23 (that is, the direction perpendicular to the thickness direction of the heat receiving plate 22 and the heat radiating plate 23). . That is, the heat dissipation member 27 is disposed so as not to face the heat receiving member 26. A heat sink 28 as a cooler is provided on the outer surface of the heat radiating plate 23 where the heat radiating member 27 is disposed.

The heat sink 28 may be integrally formed with the heat sink 23 by cutting or forging. Alternatively, the heat sink 28 may be manufactured separately from the heat radiating plate 23 and then connected to each other by a heat conductive grease or a heat conductive sheet.

The heat dissipation member 27 is composed of a plurality of fins arranged at regular intervals. The plurality of pins includes a plurality of rectangular parallelepiped members or pin fins (pin fins in the present embodiment) whose surfaces are roughened in order to promote condensation of the refrigerant C2 that has become gas. In the heat receiving member 26 made of this pin fin, in order to improve the fluidity of the refrigerant C, it is preferable to arrange a plurality of pin fins in a matrix.

The coolant C filled in the chamber 24 may be easily available water. When used in an electronic device or the like, it is preferable to use an organic refrigerant having insulation as the refrigerant C. This is because, when the refrigerant C leaks, etc., when the refrigerant C touches the electronic component or the substrate, the electronic component or the substrate is not affected and can be reused. Furthermore, many organic refrigerants have a surface tension smaller than that of water and a boiling point smaller than that of water. For this reason, it is possible to suppress the heat generating body 10 to temperature lower than the boiling point of water.

After injecting the refrigerant C into the chamber 24, the inside of the chamber 24 is evacuated to lower the boiling point. As a result, the temperature of the heating element can be maintained at a lower temperature. After evacuating the chamber 24, the refrigerant inlet 21C is caulked and sealed. Alternatively, the inside may be sealed by closing with a mounting plug of the refrigerant inlet 21C.

Regarding the arrangement relationship between the heat receiving member 26 and the heat radiating member 27, as described above, the heat receiving member 26 and the heat radiating member 27 are separated from each other in the surface direction of the heat receiving plate 22 and the heat radiating plate 23. That is, the heat radiating member 27 is not provided immediately above the heat receiving member 26. The reason is that if the heat receiving member 26 and the heat radiating member 27 are close to each other, the gas generated in the heat receiving member 26 is immediately deprived of heat by the heat radiating plate, and droplets are generated. This is because the movement of the gas generated in the heat receiving member 26 is hindered. The distance between the heat receiving member 26 and the heat radiating member 27 is preferably at least the width of the heat generating element 10.
The height of the heat receiving member 26 is preferably set so as to be 1 mm or more away from the facing surface of the heat radiating plate 23 at the opposite position in consideration of the heat transfer efficiency to the refrigerant C. Similarly, considering the heat transfer efficiency to the refrigerant C, the height of the heat radiating member 27 is preferably set to be 1 mm or more away from the facing surface of the heat receiving plate 22 at the opposite position.

Next, the effect | action of the boiling cooler 20 of this embodiment is demonstrated in detail.
The refrigerant C sealed in the chamber 24 is saturated vapor pressure by being evacuated, and has a boiling point in a normal temperature environment. The saturated vapor pressure is a maximum pressure generated in a space at a certain temperature in a sealed space where only a substance such as water exists. Thus, the liquid refrigerant C1 and the gas refrigerant C2 coexist in the sealed space in the chamber 24. The liquid refrigerant C1 exists in the lower part of the sealed space, and the gas refrigerant C2 exists in the upper part of the sealed space.

When the heating element 10 such as LSI or IC generates heat, the heat reaches the heat receiving member 26 in the chamber 24 via the heat receiving plate 22 and heats the liquid refrigerant C1 around the heat receiving member 26. When the heated refrigerant C1 reaches the boiling point, bubbles are formed with an acute shape as a nucleus.

When heat is further applied from the heat receiving member 26 to the liquid refrigerant C1, bubbles develop. When the bubbles become a certain size, the buoyancy of the bubbles becomes larger than the suction force on the surface of the heat receiving member 26 due to the surface tension. As a result, the bubbles are detached. At this time, since the space in the area where the bubbles existed is released, the surrounding liquid refrigerant C1 flows into the area and new boiling begins to occur.

As described above, since the surface of the heat receiving member 26 is roughened, a large number of acute shapes are present, so that boiling occurs on the entire fin surface of the heat receiving member 26. Due to this boiling, the liquid refrigerant C1 changes into a gaseous refrigerant C2. At this time, since the volume of the refrigerant C is several hundred times, the pressure of the sealed space in the chamber 24 increases. Thereby, gaseous refrigerant | coolant C2 moves to the upper radiation member 27 side. In this way, the gaseous refrigerant C <b> 2 that has moved to the heat radiating member 27 is brought into contact with the fins of the heat radiating member 27 so that heat is taken away and condensed. As a result, a droplet centering on the nucleus is generated in an acute shape formed on the surface of the fin.

When the droplet grows and the gravity of the droplet becomes larger than the adsorption force due to the surface tension of the heat radiating member 27, the droplet is detached from the heat radiating member 27 downward. Since the region where the droplets are attached is released by this separation, the gaseous refrigerant C comes into contact with the fin surface of the heat radiating member 27 and new condensation occurs. Since the fin surface constituting the heat radiating member 27 is roughened to have a large number of acute shapes, condensation occurs on the entire fin of the heat radiating member 27.

The droplets generated by the condensation in the heat radiating member 27 are recirculated to the liquid refrigerant C1 existing below the heat radiating member 27 and further transported to the heat receiving member 26, so that the liquid refrigerant C1 becomes the gaseous refrigerant C2 again. And phase change. On the other hand, the heat taken away from the gaseous refrigerant C1 by the heat radiating member 27 is radiated to the air or the like via the heat sink 28 attached to the outer surface of the chamber 24.

In this way, by using the phase change and volume change of the refrigerant C, the refrigerant C is moved while causing a pressure difference between the heat receiving member 26 and the heat radiating member 27, so that copper, which is a metal having good thermal conductivity, is obtained. Compared to several times to several tens of times the heat transport capability can be obtained.

Also, the heat receiving member 26 and the heat radiating member 27 are arranged apart from each other in the surface direction of the heat receiving plate 22 and the heat radiating plate 23, that is, they are in a positional relationship that does not face each other. For this reason, the heat receiving member 26 and the heat radiating member 27 are not affected by each other, and it is possible to set an optimum and free contact position and contact area with the refrigerant.

When the heat receiving member 26 and the heat radiating member 27 are close to each other, the gas generated in the heat receiving member 26 may be deprived of heat by the heat radiating member 27 present in the immediate vicinity to generate droplets.
On the other hand, in the boiling cooler 20 of the present embodiment, the heat receiving member 26 and the heat radiating member 27 are arranged in a positional relationship that does not face each other. For this reason, the movement of the gas generated in the heat receiving member 26 is not hindered, and as a result, a decrease in heat conduction efficiency can be prevented.

As described above in detail, in the boiling cooler 20 shown in the present embodiment, the refrigerant C sealed in the sealed space of the chamber 24 is changed into a liquid / gas phase between the heat receiving member 26 and the heat radiating member 27. I am letting. Thereby, the heat generated in the heating element 10 can be efficiently transported to the heat sink 28. Further, the heat receiving member 26 and the heat radiating member 27 are spaced apart from each other in the surface direction of the heat receiving plate 22 and the heat radiating plate 23. That is, the heat receiving member 26 and the heat radiating member 27 are arranged in a positional relationship that does not face each other. With this configuration, the movement of the refrigerant C1 that is a gas in the heat receiving member 26 is not hindered, and the heat conduction efficiency can be maintained high. Therefore, it is possible to efficiently dissipate heat with a simple configuration, and it is possible to deal with the heating element 10 having a large calorific value.

Further, the heat receiving plate 22 and the heat radiating plate 23 are arranged to face each other, the heat generating plate 10 and the heat receiving member 26 are provided on the heat receiving plate 22, and the heat radiating member 27 and the heat sink 28 are provided on the heat radiating plate 23. With this configuration, it is possible to reliably change the phase of the refrigerant C to liquid / gas between the heat receiving member 22 and the heat radiating member 23.

The heating element 10 such as LSI, IC, etc. mounted at a high heat generation density will become a high temperature and malfunction if it does not immediately transport the generated heat, resulting in failure of operation. In this regard, in the present embodiment, the heat generated in the heating element 10 can be quickly transported by improving the equivalent thermal conductivity. Therefore, even if the heating element 10 is mounted at a high heat generation density, the heat is efficiently diffused without staying at a specific place, and the temperature of the heating element 10 can be lowered.

Further, it is not necessary to divide the flow path of the refrigerant C1 in which the phase change is performed between the heat receiving plate 22 and the heat radiating plate 23. That is, there is no need to consider the refrigerant movement path from the heat receiving plate 22 toward the heat radiating plate 23 and the refrigerant movement path from the heat radiating plate 23 to the heat receiving plate 22. When such a refrigerant moving flow path is considered, fine fine adjustment is required every time the design is changed, but in the present embodiment, it is only necessary to consider the arrangement of the heat receiving plate 22 and the heat radiating plate 23. Therefore, design difficulties do not occur, and the overall configuration can be simplified.

In the boiling cooler 20, heat transport from a plurality of heating elements 10 can be simultaneously performed by using a heat transporter on a flat plate. This eliminates the need for a plurality of parts for transporting heat. Furthermore, it becomes possible to integrate a plurality of required coolers such as a heat sink into one, and heat sinks and fans can be reduced. As a result, the entire apparatus can be reduced in size and thickness.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
In the boiling cooler 20 of the said 1st Embodiment, the heat receiving member 26 was comprised with the several columnar pin fin which was provided in the heat receiving plate 22 with which the heat generating body 10 is arrange | positioned, and made the surface rough. As shown in FIG. 4, the heat receiving member 26 may be configured by rectangular fins 30 in which a plurality of rectangular parallelepiped members are arranged at regular intervals.
The heat receiving member 26 constituted by the rectangular fins is constituted by a rectangular parallelepiped member having a rough surface, and the whole is formed in a comb shape.

The heat receiving member 26 preferably has a large surface area in contact with the refrigerant C, but the surface area in contact with the liquid refrigerant C is not necessarily proportional to the boiling performance. It has been confirmed that when the pin fins of the first embodiment are rectangular fins 30, the surface area in contact with the refrigerant C is reduced, but the boiling performance is not significantly reduced. In terms of productivity, the rectangular fin 30 is more advantageous than the pin fin. The rectangular fin 30 may be formed integrally with the heat receiving plate 22 by cutting or forging. Alternatively, a rectangular parallelepiped member of the rectangular fin 30 may be separately manufactured and then welded to the heat receiving plate 22 by brazing or the like, and then the surface may be roughened from about 1 μm to several hundreds of μm. Such a rectangular fin 30 may also be applied to the heat radiating member 27 connected to the heat sink 28.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
In the boiling cooler 20 of the first embodiment, the heat receiving member 26 is a plurality of columnar pin fins having a rough surface on the heat receiving plate 22 on which the heating element 10 is disposed. As shown in FIG. 5, the heat receiving member 26 may be constituted by a rectangular parallelepiped heat radiation block 31 having a rough surface.

Even if the heat receiving member 26 is formed in a block shape, the boiling performance is not significantly lowered.
Considering productivity, the block shape is easier to manufacture than a pin fin or a rectangular fin, and is advantageous in manufacturing. The heat receiving member 26 may be formed integrally with the heat receiving plate 22 by cutting or forging. Alternatively, a separately manufactured block may be welded to the heat receiving plate 22 by brazing or the like, and then the surface may be roughened from 1 μm to 100 μm.
Such a heat dissipation block 31 may also be applied to the heat dissipation member 27 connected to the heat sink 28.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG.
In the boiling cooler 20 of the first embodiment, the chamber 24 is arranged to be horizontal, but the invention is not limited to this. The boiling cooler 20 may be arranged vertically as shown in FIG. That is, the heat receiving member 26 and the heat radiating member 27 may be positioned so that the normal lines of the heat receiving member 26 and the heat radiating member 27 are orthogonal to the heat receiving plate 22 and the heat radiating plate 23 in the vertical direction. Also in this case, at least the heat receiving member 26 of the heat receiving member 26 and the heat radiating member 27 is immersed in the liquid refrigerant C1. With such a configuration, the degree of freedom in design can be increased.

In the example of the boiling cooler 20 shown in FIG. 6, the heat receiving member 26 connected to the heating element 10 is provided below the heat radiating member 27 connected to the heat sink 28 in the vertical direction. With such a configuration, the heat receiving member 26 that has received the heat of the heating element 10 transfers heat to the liquid refrigerant C1 to change the phase of the refrigerant C1 to generate bubbles. The bubbles generated here move upward in the vertical direction by buoyancy, and come into contact with the heat radiating member 27 connected to the heat sink 28 serving as a cooler, and heat is taken away. As a result, the gaseous refrigerant C2 is condensed into droplets.

The positional relationship between the heat receiving member 26 and the heat radiating member 27 may be that the heat radiating member 27 is below the heat receiving member 26 or the heat radiating member 27 is above the heat receiving member 26.
However, it is necessary to inject the refrigerant C up to at least the height of the heat receiving member 26 so that the heat receiving member 26 is immersed in the liquid refrigerant C1. As a result, regardless of the positional relationship, the heat receiving member 26 on which the heating element 10 is mounted is immersed in the liquid refrigerant C. Boiling occurs by the heat receiving member 26 and circulation using the phase change occurs, and heat is transmitted to the entire chamber 24 and is radiated by the heat sink 28.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG.
In the boiling cooler 20 of the first embodiment, the heat receiving member 26 is arranged on the heat receiving plate 22 constituting the chamber 24, and the heat radiating member 27 is arranged on the heat radiating plate 23 facing the heat receiving plate 22. In the fifth embodiment, as shown in FIG. 7, the heat receiving member 26 and the heat radiating member 27 may be arranged on one heat conducting plate 32.

By adopting the heat conductive plate 32, the number of parts can be reduced and productivity can be improved by sharing the members. The heat conductive plate 32 is made of, for example, metal. The heat of the heating element 10 is transferred from the heat receiving member 26 to the heat radiating member 27 by transferring the metal, and a synergistic effect combined with heat transport through the refrigerant C can be exhibited.

The heat receiving and radiating member 32 may be manufactured by cutting or forging. Or you may attach the heat-receiving member 26 and the fin of the heat radiating member 27 which were produced separately by brazing. The sealing plate 33 disposed so as to face the heat conductive plate 32 may be made of aluminum or copper having good heat conductivity, or may be made of a resin such as acrylic in consideration of productivity.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIGS.
In the boiling cooler 20 of the first embodiment, the chamber 24 is arranged to be horizontal, but the invention is not limited to this. As shown in FIGS. 8 to 10, in the sixth embodiment, the boiling cooler 10 is arranged vertically as shown in FIGS. 9 and 10, and the buffer tank 40 is arranged in the upper position thereof. Also good.

That is, when the heating element 10 is installed in the vicinity of the upper end of the heat sink 28 in the vertical direction, the heat receiving member 26 connected to the heating element 10 must be immersed in the liquid refrigerant C1. As a result, most of the interior of the chamber 24 is occupied by the liquid refrigerant C1. However, when the liquid refrigerant C1 is mostly occupied in the internal space of the chamber 24, the volume of the liquid refrigerant C1 is increased by vaporizing the liquid refrigerant C1 into the gas refrigerant C2 due to the phase change in the heat receiving member 26. . As a result, there is no space in which the refrigerant C can be stored, and the pressure in the chamber 24 rises more than necessary. In this case, since the boiling point of the refrigerant C increases, the heating element 10 may not be cooled to a predetermined temperature.

In order to suppress such an increase in internal pressure, the buffer tank 40 shown in FIGS. 8 to 10 serves as an evacuation site for the gaseous refrigerant C2. The buffer tank 40 is disposed so as to protrude above the heat sink 23. A buffer space for accommodating the gaseous refrigerant C2 is formed inside the buffer tank 40. The buffer tank 40 is arranged above the heat sink 23 in the vertical direction and above the heat sink 28. On the other hand, the heat receiving member 26 connected to the heating element 10 is disposed at a position facing the buffer tank 40.

FIG. 10 shows an operation diagram of the refrigerant C at this time. In the heat receiving member 26 connected to the heating element 10, the liquid refrigerant C1 boils and bubbles are generated. When the bubbles are detached from the heat receiving member 26, the space occupied by the bubbles (gaseous refrigerant C1) is opened, and the liquid refrigerant C2 flows into the space to cause circulation. Thereby, the heat of the heating element 10 is diffused throughout the chamber 24 and is radiated in the air by the heat sink 28 mounted on the heat radiating member 27 at the lower part in the vertical direction.

At this time, the gas generated by the heat receiving member 26 can be stored in the internal space of the buffer tank 40 installed on the upper part of the heat sink 23. As a result, an increase in internal pressure in the chamber 24 can be suppressed, and a cooling effect can be brought out even for the heating element 10 installed on the upper portion of the chamber 24. Further, when the amount of heat of the heating element 10 is large, it is necessary that a large amount of liquid refrigerant C2 exists near the heat receiving member 26 because the amount of boiling liquid refrigerant C2 is large. In that case, by storing the refrigerant C in a part of the buffer tank 40 to supplement the insufficient refrigerant C, it is possible to cope with the heating element 10 having a large calorific value.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included.

This application claims priority based on Japanese Patent Application No. 2010-115539 filed on May 19, 2010, the entire disclosure of which is incorporated herein.

The present invention can be applied to a boiling cooler. According to this boiling cooler, heat generation of LSI and IC can be suppressed by utilizing a phase change phenomenon of refrigerant such as boiling and liquefaction.

10 Heating element 20 Boiling cooler
21 Side plate
22 Heat receiving plate
23 Heat sink
24 chambers
26 Heat receiving member
27 Heat dissipation member
28 Heat sink
32 Heat conduction plate
C1 (C) Liquid refrigerant
C2 (C) Gaseous refrigerant

Claims

A heat conduction plate provided with an exothermic body on the outer surface, and a chamber having a sealed space provided inside the heat conduction plate and filled with a refrigerant that changes phase between liquid and gas;
A heat sink provided on the outer surface of the heat conducting plate;
A heat receiving member that is provided on an inner surface of the heat conductive plate so as to face the heat generating member across the heat conductive plate, and that transfers heat generated by the heat generating member to the refrigerant;
A heat dissipating member that is provided on the inner surface of the heat conducting plate, receives heat transferred by the refrigerant, and dissipates heat to the heat sink;
The heat receiving member and the heat radiating member are arranged apart from each other in the surface direction of the heat conducting plate,
A boiling cooler in which the heat receiving member is immersed in the liquid refrigerant.
The heat conducting plate is a heat receiving plate and a heat radiating plate arranged to face each other across the sealed space,
The heating element and the heat receiving member are provided on the heat receiving plate,
The boiling cooler according to claim 1, wherein the heat sink and the heat radiating member are provided on the heat radiating plate.
The height of the heat receiving member from the heat receiving plate and the height of the heat radiating member from the heat radiating plate are set to approximately one-half the distance between the heat receiving plate and the heat radiating plate, respectively. The boiling cooler according to claim 2.
The heat receiving member is separated from the inner surface of the heat sink by at least 1 mm,
4. The boiling cooler according to claim 2, wherein the heat radiating member is separated from the inner surface of the heat receiving plate by at least 1 mm or more. 5.
The boiling cooler according to any one of claims 1 to 4, wherein the heat receiving member and the heat radiating member are formed of a plurality of fins erected on an inner surface of the heat conducting plate.
The boiling cooler according to any one of claims 1 to 4, wherein the heat receiving member and the heat radiating member are cuboid blocks fixed to an inner surface of the heat conducting plate.
The boiling cooler according to any one of claims 1 to 6, wherein the surface of the heat receiving member and the heat radiating member is subjected to a surface roughening process having a surface roughness in a range of 1 µm to 100 µm.
The boiling cooler according to any one of claims 1 to 7, wherein the chamber includes a buffer tank into which the gaseous refrigerant enters.
The boiling cooler according to claim 1, wherein the heat receiving member and the heat radiating member are immersed in the liquid refrigerant.