JP2016173216A - Cooling device and electronic device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device which supplies a necessary amount of a refrigerant to a heat receiving part according to fluctuation of heat of a heating element to achieve stable cooling performance.SOLUTION: A cooling device 1 cools a heating element 2 with phase change of a refrigerant. In the cooling device 1, a heat receiving part 3 in which the heating element 2 is installed, a heat radiation passage 5, a heat radiation part 4, and a feedback path 6 are sequentially connected to form a circulation passage of the refrigerant. The feedback path includes a liquid tank. The liquid tank includes a first connection part and a second connection part. The liquid tank is detachably connected to the feedback path by the first connection part and the second connection part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling device for an electronic device in which electronic components such as a central processing unit (CPU), a large scale integrated circuit (LSI), and an insulated gate bipolar transistor (IGBT) are mounted, and an electronic device in which the electronic device is mounted. .

  Conventionally, this type of cooling device has the following configuration.

  That is, as shown in FIG. 3, the heat receiving portion 102 arranged along the heating element 101, the steam pipe 103 extending vertically upward from one end portion of the heat receiving portion 102, and the position higher than the heat receiving portion 102. And a heat radiating section 104 cooled by the outside air as a cooling medium and having the steam pipe 103 connected downward from above, and a liquid reflux pipe connecting the lower end of the heat radiating section 104 and the other end of the heat receiving section 102 105 in a loop type heat pipe having a sealed annular shape as a whole and having received a heat from the outside to evaporate and dissipates and condenses the working fluid 106 inside, the range from the liquid reflux tube 105 to the heat receiving portion 102 A reserve tank 107 storing a liquid-phase working fluid 106 is connected to a predetermined portion of the storage tank 107, and the reserve tank 107 is provided with a pressurizing unit 108. It has become a working fluid 106 and configured to be pressurized.

  In the loop heat pipe having such a configuration, the working fluid 106 evaporates in the heat receiving portion 102, and the steam flows upward through the steam pipe 103 toward the heat radiating portion 104, and the steam is heated in the heat radiating portion 104. Is deprived and condensed. Then, the condensed working fluid 106 flows back to the heat receiving unit 102 through the liquid recirculation pipe 105 due to a water head difference, and the heating element 101 is cooled.

  At this time, if the heat load of the heating element 101 increases, the working fluid 106 evaporates in the heat receiving portion 102 and the working fluid 106 condenses in the heat radiating portion 104, so the working fluid 106 is insufficient in the heat receiving portion 102. Dry out is likely to occur.

  However, in this configuration, since the working fluid 106 is additionally supplied from the reserve tank 107 to the liquid reflux pipe 105 and the heat receiving unit 102, the heat receiving unit 102 is not partially dry out. Further, since the working fluid 106 in the reserve tank 107 is pressurized by the pressurizing unit 108, the working fluid 106 is surely secured even when the pressure in the heat receiving unit 102 is high due to a large heat load. (See, for example, Patent Document 1).

Japanese Utility Model Publication No. 63-197982

In the cooling device disclosed in Patent Document 1, a valve 109, a gas cylinder 110, and a pressure gauge 111 are shown as the pressurizing unit 108, and the gas cylinder 110 is connected to the reserve tank 107 via the valve 109. The pressure gauge 111 is provided between the valve 109 and the reserve tank 107. The gas cylinder 110 is filled with an incompressible gas (for example, Ar or N ₂ ), and the reserve tank 107 and the gas cylinder 110 are separated by an elastic film so that the incompressible gas is not mixed into the working fluid 106. It has become.

  In the above configuration, it is necessary to open the valve 109 when the heat load becomes large, but the control is not described, and when the heat load suddenly increases, the additional supply of the working fluid 106 is not in time. There was a problem that dryout would occur.

  In addition, once the pressure is increased, the incompressible gas does not naturally return to the gas cylinder 110. Therefore, when the thermal load is reduced, the additionally supplied working fluid 106 becomes redundant, and the circulation of the working fluid 106 is obstructed. However, there is a problem that the cooling performance is lowered. In order to return the working fluid 106 to the reserve tank 107, the gas cylinder 110 is removed from the valve 109 when the connecting portion between the reserve tank 107 and the liquid reflux pipe 105 is filled with the liquid-phase working fluid 106, and the incompressible gas is discharged. It is necessary to take out the work, but it is a very complicated work.

  Accordingly, the present invention is to solve the above-described problems, and an object of the present invention is to provide a cooling device that supplies a necessary amount of a required working fluid even when a thermal load fluctuates and obtains a stable cooling performance. To do.

  Accordingly, in order to achieve this object, the present invention provides a cooling device that cools a heating element by a phase change of a working fluid, and includes a heat receiving portion, a heat dissipation path, a heat dissipation section, and a return path provided with a heat receiving plate on which the heating element is installed Are connected in order to form a circulation path for the working fluid, and the heat dissipating part includes a header part for temporarily storing the working fluid in a lower part, and the header part and the return path are connected to each other. The return path includes a liquid tank, the liquid tank includes a first connection portion and a second connection portion, and the liquid tank includes the first connection portion and the second connection portion in the return path. Thus, the cooling device is detachably connected to the return path, thereby achieving the initial purpose.

  As described above, in the cooling device of the present invention, by providing the liquid tank in the return path, the working fluid can be temporarily stored in the liquid tank, and the working fluid that can sufficiently cover the maximum heating value of the heating element is enclosed. Thus, even if the heat of the heating element suddenly increases, the necessary working fluid can be supplied to the heat receiving portion, so that dryout can be prevented.

  Further, by providing the liquid tank in the return path, the extra working fluid does not hinder the circulation of the steam generated in the heat receiving part in the heat dissipation path and does not deteriorate the cooling performance.

  In addition, since the liquid tank can be detached from the return path by the first connection part and the second connection part, the liquid tank can be removed if necessary, and can be replaced with a tank with a different volume. Maintenance workability is not impaired.

  According to the above, even when the heat fluctuates, the working fluid is supplied in a necessary amount, and a stable cooling performance can be obtained.

Schematic of an electronic device equipped with the cooling device of Embodiment 1 of the present invention Schematic of the electronic device carrying the cooling device of Embodiment 2 of this invention Configuration diagram of conventional cooling system

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram of an electronic device 30 on which the cooling device 1 according to Embodiment 1 of the present invention is mounted.

  As shown in FIG. 1, an electronic device 30 includes a power semiconductor element that becomes a heating element 2 and a cooling device 1 that cools the heating element 2 in a case 31.

  The cooling device 1 includes a heat receiving portion 3 having a heat receiving plate (not shown) to which the heat generating element 2 is attached, and a heat radiating portion 4. 4 is connected annularly and the inside of the cooling device 1 is a sealed space.

  The cooling device 1 is a boiling cooler in which the working fluid 7 is sealed after the pressure is reduced, and the heating element 2 can be cooled by the latent heat of evaporation. As the working fluid 7, for example, pure water, ethanol, fluorine-based solvents, chlorofluorocarbon refrigerant, or the like is used.

  In addition, the cooling device 1 includes a fan 8 that blows outside air to the heat radiating unit 4, and finally radiates heat transported by the working fluid 7 to the outside air. A header portion 9 that can temporarily store the working fluid 7 is provided below the heat radiating portion 4, and the return path 6 connects the header portion 9 and the heat receiving portion 3.

  Here, the heat radiating unit 4 is, for example, an aluminum radiator, and heat exchange between a flat medium that passes through the inside of the multi-tube having a large number of holes and outside air that has many corrugated fins and passes through the outside. It is designed to be done efficiently.

  The return path 6 is provided with a backflow prevention section 10 on the heat receiving section 3 side in order to prevent the backflow of the working fluid 7 from the heat receiving section 3 to the return path 6 side. Is provided with a liquid tank 11 that can sufficiently store the liquid-phase working fluid 7.

  The liquid tank 11 includes a first opening 12 and a second opening 13, and connects the first opening 12 and the header section 9 side of the return path 6 to be openable / closable and detachable; The opening 13 and the heat receiving part 3 side of the return path 6 are connected to each other, and a second connecting part 15 that can be opened and closed and detached is provided.

  That is, the liquid tank 11 communicates with the return path 6 via the first connection portion 14 and the first opening 12, and similarly communicates with the return path 6 via the second connection portion 15 and the second opening 13.

  For example, a ball valve, a gate valve, a needle valve, a globe valve, a stop valve, or the like is used for the first connection portion 14 and the second connection portion 15. When the liquid tank 11 is attached to or detached from the return path 6, the working fluid 7 is used. It is possible to prevent leakage and to ensure airtightness.

  Next, the basic operation of the cooling device 1 will be described.

  The cooling device 1 receives heat generated by driving the heating element 2 by the heat receiving unit 3, and this heat is transmitted to the internal working fluid 7 and boiled, so that the phase is changed to steam. You can take heat away from.

  The vapor of the working fluid 7 flows into the heat radiating section 4 due to the pressure difference, condenses in the heat radiating section 4 cooled by the outside air by the fan 8, and changes into the liquid phase. Is supplied again to the heat receiving section 3 through the return path 6 connected to the header section 9 and the backflow prevention section 10.

  Here, the action of the pressure difference means that the pressure of the working fluid 7 flows from the heat receiving portion 3 toward the heat radiating portion 4 because the pressure in the heat radiating portion 4 is relatively smaller than that in the heat receiving portion 3. Means. This is because the inside of the cooling device 1 is a single sealed space connected in an annular shape with a limited internal volume, so that the working fluid 7 exists in a saturated pressure state. The saturation pressure is smaller in the heat radiating section 4 cooled by the outside air than in the heat receiving section 3 warmed by the heating element 2.

  Here, the circulation direction of the working fluid 7 is defined in one direction by the backflow prevention unit 10. That is, the backflow prevention unit 10 uses, for example, a porous metal sintered body, a metal fiber sintered body, a reduced diameter reduced portion, a thin tube, a bent tube, a valve body, etc. 7 is urged to circulate to the heat radiating portion 4 side of the heat radiating path 5. The action of supplying the working fluid 7 to the heat receiving unit 3 is stored in the pressure difference generated between the heat receiving unit 3 and the heat radiating unit 4, the flow resistance of the backflow prevention unit 10, the return path 6 and the liquid tank 11. It is obtained by the head pressure of the liquid-phase working fluid 7 and the balance thereof.

  Thus, the heating fluid 2 is cooled by circulating the inside of the cooling device 1 in one direction with the phase change and radiating the heat of the heating element 2 to the outside air.

  Here, the working fluid 7 evaporates due to the heat of the heating element 2, that is, the circulation flow rate of the working fluid 7 is determined by the heat generation amount of the heating element 2. In a state where the calorific value is stable, the vapor amount of the working fluid 7 generated by the boiling of the working fluid 7 in the heat receiving portion 3 is equal to the liquid amount of the working fluid 7 that flows into the heat radiating portion 4 and condenses. In addition, since a sufficient amount of the liquid-phase working fluid 7 is stored in the liquid tank 11 and the return path 6, the circulation and cooling performance of the working fluid 7 is stable regardless of the amount of heat generated.

  Next, the liquid tank and its operation, which are the features of this embodiment, will be described.

  When the heat of the heating element 2 suddenly increases, more working fluid 7 boils in the heat receiving section 3 and the liquid-phase working fluid 7 in the return path 6 temporarily decreases greatly. If the liquid-phase working fluid 7 is not sufficiently stored as in the liquid tank 11, the head pressure in the operation of supplying the working fluid 7 to the heat receiving portion 3 is greatly reduced although it is temporary. The working fluid 7 in 3 is insufficient and it becomes easy to dry out.

  However, in the present embodiment, since the liquid tank 11 is provided and a sufficient amount of the working fluid 7 is stored, even if the heat of the heating element 2 suddenly increases, it is stored in the liquid tank 11. Since a sufficient amount of the working fluid 7 is supplied to the return path 6, there is no shortage of refrigerant in the return path 6 even temporarily, and the head pressure for supplying the working fluid 7 to the heat receiving unit 3 is sufficient. As a result, dryout can be prevented.

  The liquid tank 11 in the present embodiment is connected to the return path 6 by the first connecting portion 14 and the second connecting portion 15. Thereby, inflow and outflow of the working fluid 7 in the gas phase and the liquid phase stored in the liquid tank 11 becomes smooth.

  That is, for example, if the liquid-phase working fluid 7 has been stored up to about half of the internal volume of the liquid tank 11, the remaining half of the internal volume is filled with the gas-phase working fluid 7, and the heat dissipating part from the liquid tank 11. The four-side return path 6 is also filled with the gas-phase working fluid 7. At this time, when the heat of the heating element 2 suddenly increases, the liquid-phase working fluid 7 is temporarily supplied from the liquid tank 11 to the return path 6 via the second connection portion 15 and simultaneously the first connection. Since the gas-phase working fluid 7 flows in from the part 14 side, the liquid tank 11 has the same pressure as that in the return path 6, so that the working fluid 7 flows in and out smoothly.

  Thereafter, the liquid-phase working fluid 7 gradually condensed in the heat radiating section 4 flows into the return path 6 via the header section 9, and at this time, most of the working fluid 7 is connected to the first connection. The liquid flows into the liquid tank 11 from the portion 14. Since the gas-phase working fluid 7 in the liquid tank 11 flows out from the second connection portion 15 toward the return path 6, the working fluid 7 is stored in the liquid tank 11 again.

  The internal volume of the liquid tank 11 is preferably larger than the internal volume of the return path 6, and even if the heat of the heating element 2 fluctuates, the necessary amount of working fluid 7 is supplied to the heat receiving unit 3. Since the liquid-phase working fluid 7 is not lost from the liquid tank 11, the water head pressure necessary for supplying the working fluid 7 to the heat receiving section 3 can be stably obtained, and the cooling performance can be further stabilized. The reliability of the cooling device 1 can be improved.

  In the cooling device 1, the working fluid 7 that sufficiently covers the maximum value of the heat generation amount of the heating element 2 is sealed in advance, and the capacity thereof is adjusted by an amount that can be accommodated in the return path 6 and the liquid tank 11, The liquid level of the liquid-phase working fluid 7 is preferably adjusted so as to be in the liquid tank 11.

  In the present embodiment, the liquid tank 11 is detachable. That is, the liquid tank 11 is closed by closing the first connection portion 14, closing the second connection portion 15, removing the first connection portion 14 from the first opening 12, and removing the second connection portion 15 from the second opening 13. Can be removed from the return path 6. The reverse procedure is carried out at the time of wearing.

  As a result, the cooling device 1 can be easily assembled, inspected, and maintained, and the capacity of the liquid tank 11 can be changed. Therefore, the capacity of the liquid tank 11 is insufficient after the cooling apparatus 1 is installed. Can also be exchanged.

  The first connecting portion 14 may be a three-way valve. In that case, the first connecting portion 14 is connected to the return path 6 and the first opening 12, and in addition, there is a connecting port on the atmosphere opening side. The vacuum in the cooling device 1 can be increased and reduced by connecting a vacuum pump to the connection port and communicating the return path 6 with the vacuum pump. Further, the working fluid 7 can be additionally replenished by connecting a refrigerant tank to the connection port and communicating the liquid tank 11 and the refrigerant tank. Thereby, the maintenance work of the cooling device 1 can be facilitated.

  In this embodiment, the cooling is performed by the air cooling method using the fan 8, but a water cooling method or other methods may be used.

  The liquid tank 11 preferably has a cylindrical shape with excellent pressure resistance.

  The liquid tank 11 may be provided with a sight glass (not shown). In this case, the presence or absence of the liquid inside can be visually confirmed.

  Note that a charge valve (not shown) may be provided in the heat dissipation path 5, and in this case, the inside of the cooling device 1 can be additionally evacuated.

(Embodiment 2)
Embodiment 2 of the present invention will be described below with reference to the drawings.

  FIG. 2 is a schematic diagram of an electronic device 30 on which the cooling device 1 according to Embodiment 2 of the present invention is mounted.

  The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the liquid tank 11 communicates with the header portion 9 via the first connection portion 14 and communicates with the return path 6 via the second connection portion 15.

  In this configuration, since both the return path 6 and the liquid tank 11 communicate with the header section 9, the liquid-phase working fluid 7 condensed in the heat radiating section 4 can flow out to both the return path 6 and the liquid tank 11. The circulation of the working fluid 7 becomes smoother.

  Other functions and effects are the same as those of the first embodiment, and a description thereof will be omitted.

  As described above, the cooling device according to the present invention can supply a necessary amount of the refrigerant to the heat receiving portion in accordance with the fluctuation of the heat of the heating element, so that a stable cooling performance is obtained, and the reliability is high. It is useful as a cooling device for equipment.

DESCRIPTION OF SYMBOLS 1 Cooling device 2 Heat generating body 3 Heat receiving part 4 Heat radiation part 5 Heat radiation path 6 Return path 7 Working fluid 8 Fan 9 Header part 10 Backflow prevention part 11 Liquid tank 12 First opening 13 Second opening 14 First connection part 15 Second connection Part 30 Electronic equipment 31 Case

Claims (5)

In the cooling device that cools the heating element by the phase change of the working fluid,
A heat receiving part provided with a heat receiving plate for installing the heating element, a heat radiation path, a heat radiation part, and a return path are connected in order to form a circulation path for the working fluid,
The heat dissipating part includes a header part for temporarily storing a working fluid in a lower part,
The header part and the return path are connected to each other,
The return path includes a liquid tank,
The liquid tank includes a first connection portion and a second connection portion,
The cooling device, wherein the liquid tank is detachably connected to the return path through the first connection part and the second connection part in the return path. The cooling device according to claim 1, wherein the return path includes a backflow prevention unit, and the backflow prevention unit is disposed between the liquid tank and the heat receiving unit. The liquid tank is characterized in that the first connection portion and the header portion are connected between the header portion and the backflow prevention portion in the return path, and the second connection portion and the return path are connected. The cooling device according to 1 or 2. 4. The cooling device according to claim 1, wherein the internal volume of the liquid tank is larger than the internal volume of the return path. The cooling device according to any one of claims 1 to 4, wherein the first connection portion is a three-way valve.

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