JP5532816B2 - Loop type heat pipe and electronic device equipped with the same - Google Patents

Description

  The present invention relates to a loop heat pipe used for cooling a heating element or the like and an electronic apparatus including the same.

  In recent years, the heat generation amount and heat generation density of electronic devices such as computers have increased, and improvement in cooling performance has been demanded. For this reason, a method is widely used in which a heat sink is disposed in a location suitable for cooling, such as in the vicinity of a cooling fan, and an electronic component having a large amount of heat, such as a CPU, and the heat sink are thermally connected by a heat pipe. Conventionally, as a heat pipe for thermally connecting a heat sink and an electronic component, a single-tube heat pipe having a simple structure has been used. However, the heat transport capacity of the single-tube heat pipe is as low as about 30 to 50 W, and may not be sufficient for cooling the electronic device. On the other hand, loop type heat pipes have better heat transport capability than single pipe type heat pipes, so development aimed at mounting on electronic devices is underway.

  The loop heat pipe temporarily stores an evaporating unit that evaporates the working fluid (liquid phase working fluid), a condensing unit that condenses the vapor (gas phase working fluid), and the working fluid supplied to the evaporating unit. A compensation chamber. The evaporating part and the condensing part are connected by a steam pipe that guides the steam, and the condensing part and the compensation chamber are connected by a liquid pipe that guides the working fluid. Inside the evaporation section, a porous member called a wick is provided that separates the working liquid flow path communicating with the liquid pipe and the vapor flow path communicating with the steam pipe. This wick has a function of sucking up the hydraulic fluid in the hydraulic fluid flow path with a capillary force and transporting it to the vapor flow path side, and a function of preventing the vapor in the vapor flow path from flowing backward to the hydraulic fluid flow path side. Circulates the working fluid between the gas and the condenser.

  By the way, electronic devices such as computers are arranged in various directions depending on installation, transportation, storage, and the like. Therefore, it is assumed that the loop heat pipe mounted on the electronic device has a so-called top heat arrangement in which the evaporation portion (high temperature portion) is located above the condensation portion (low temperature portion). In this case, when the operation is stopped, the hydraulic fluid flows out of the compensation chamber and the evaporation section due to gravity, and the function of transporting the hydraulic fluid by the wick to the vapor flow path side and the function of preventing the vapor from flowing back to the hydraulic liquid flow path side do not work. This makes it impossible to start the loop heat pipe.

  In order to prevent the above problems, a porous filter and a heating device were provided in the piping on the condensation side of the loop heat pipe, and a part of the working fluid collected in the condensation portion at the start was evaporated by the heating device. There is a method in which hydraulic fluid is pushed up to the evaporation section by vapor pressure and supplied to the wick.

JP 2009-168273 A JP 2009-115396 A Japanese Patent Laid-Open No. 2002-340489

  However, in the above-described method, it is necessary to provide a porous filter in the flow path of the working fluid, which increases the flow resistance of the working fluid and reduces the heat transport capability.

  Then, it aims at providing the loop type heat pipe excellent in startability and heat transport capability, and an electronic device provided with the same.

According to one aspect, an evaporation unit that receives heat from the outside and evaporates the working fluid, a condensing unit that radiates heat to the outside and condenses the vapor of the working fluid, and a compensation for storing the working fluid supplied to the evaporation unit a liquid pipe for guiding a chamber, a steam pipe for guiding the vapor of the working fluid generated in the evaporation section to the condensing section, the working fluid condensed by the condensing unit to the compensation chamber, disposed within said evaporator section And a wick made of a porous material that separates the working fluid passage communicating with the compensation chamber and the steam passage communicating with the steam pipe, and is disposed in the compensation chamber and operates when the temperature is lower than a predetermined temperature. There is provided a loop heat pipe having a hydraulic fluid absorbing member that absorbs fluid and expands, and contracts when the temperature is higher than the predetermined temperature to release the hydraulic fluid.

  In the above aspect, the working fluid absorbing member that absorbs the working fluid when the temperature is lower than the predetermined temperature and expands in the compensation chamber and contracts and discharges the working fluid when the temperature is higher than the predetermined temperature. Provided. The hydraulic fluid absorbing member absorbs the hydraulic fluid when the loop heat pipe is stopped, that is, when the temperature of the electronic component to be cooled is low, and releases the hydraulic fluid when the temperature of the electronic component becomes high. For this reason, even when the loop heat pipe is in a top heat arrangement and the working fluid flows out of the evaporation section, the wick can be reliably wetted by the working fluid supplied from the working fluid absorbing member, and the loop heat The startability of the pipe can be improved. Further, since it is not necessary to provide a porous filter having a large flow resistance in the flow path of the hydraulic fluid, the heat transport capability is also excellent.

Fig.1 (a) is a figure which shows the state which stopped the loop type heat pipe which concerns on embodiment in top heat arrangement | positioning, FIG.1 (b) is a compensation chamber and evaporation part in the state of Fig.1 (a) FIG. FIG. 2A is a cross-sectional view showing the evaporation part of the loop heat pipe according to the embodiment cut along a plane perpendicular to the wick axis, and FIG. It is a perspective view which decomposes | disassembles and shows a chamber. FIG. 3 is a cross-sectional view illustrating a connection structure between the evaporation unit and the compensation chamber of the loop heat pipe and the electronic component according to the embodiment. 4A and 4B are schematic diagrams showing changes in the molecular structure of the temperature-responsive polymer with temperature. FIG. 5 is a cross-sectional view illustrating a state at the start of the compensation chamber and the evaporation unit of the loop heat pipe according to the embodiment. 6A is a diagram illustrating a state in which the loop heat pipe according to the embodiment is operated in a top heat arrangement, and FIG. 6B is a cross-sectional view illustrating the compensation chamber and the evaporation unit in FIG. 6A. FIG. FIG. 7 is a perspective view illustrating a computer in which the loop heat pipe according to the embodiment is mounted.

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

  Fig.1 (a) is a figure which shows the state which stopped the loop type heat pipe which concerns on embodiment in top heat arrangement | positioning, FIG.1 (b) is a compensation chamber and evaporation part in the state of Fig.1 (a) FIG. FIG. 2A is a cross-sectional view showing the evaporation part of the loop heat pipe according to the embodiment cut along a plane perpendicular to the wick axis, and FIG. It is a perspective view which shows a chamber. FIG. 3 is a cross-sectional view illustrating a connection structure between the evaporation unit and the compensation chamber of the loop heat pipe and the electronic component according to the embodiment. In FIG. 1, an arrow A indicates a vertically upward direction, and the same applies to other drawings.

  As shown in FIG. 1A, the loop heat pipe 10 of the present embodiment includes a compensation chamber 11, an evaporation unit 12, a vapor pipe 13, a condenser pipe (condensing part) 14, and a liquid pipe 15, and inside. The working fluid 18 is enclosed together with steam having a saturated vapor pressure. Here, water is used as the working fluid 18. Note that methanol, ethanol, or the like may be used as the working fluid 18.

  As shown in FIG. 1B, the compensation chamber 11 is disposed adjacent to the evaporation unit 12 and temporarily stores the working fluid 18 supplied to the evaporation unit 12. A working fluid absorbing member 16 is disposed inside the compensation chamber 11. The hydraulic fluid absorbing member 16 has a structure in which support layers 16a and absorbent layers 16b are alternately stacked. The support layer 16a is made of a material having low chemical reactivity and solubility with respect to the working fluid 18, such as a nonwoven fabric made of polypropylene.

  In addition, the material of the support layer 16a is not limited to the above-mentioned example, For example, metal materials, such as platinum, platinum black, gold | metal | money, palladium, rhodium, silver, mercury, tungsten and copper, or these alloys , Carbon materials such as graphite and carbon fiber, semiconductor materials such as single crystal silicon, amorphous silicon, silicon carbide, silicon oxide, silicon nitride and SOI (silicon on insulator), glass, quartz glass, alumina, sapphire, various ceramics Inorganic materials such as forsterite and photosensitive glass, and various polymer materials can be used.

  The absorption layer 16b is made of a resin material that absorbs the hydraulic fluid 18 at a temperature lower than a predetermined phase transition temperature and expands, and releases the hydraulic fluid 18 at a temperature higher than the phase transition temperature to contract. Here, it is assumed that poly N-isopropylacrylamide, which is a kind of stimulus-responsive polymer (temperature-responsive polymer) that absorbs and releases hydraulic fluid depending on temperature, is used for the absorption layer 16b. Poly-N-isopropylacrylamide has a phase transition temperature of about 32 ° C., and at a temperature higher than 32 ° C., the acrylamide portion of the side chain is dehydrated and the polymer chain contracts to reduce its volume. At a temperature lower than 32 ° C., the acrylamide portion in the side chain absorbs moisture and the molecular chain expands, increasing its volume.

  In addition, the temperature-responsive polymer used for the absorption layer 16b is not limited to the above-described example. For example, poly (N-substituted acrylamide), poly (N-substituted methacrylamide), poly (N, N -Disubstituted acrylamide), poly (N, N-disubstituted methacrylamide), polyvinyl ether (which may be partially substituted), and the like can be used. Here, the substituent of the above-described material is a linear or branched alkyl group having 1 to 20 carbon atoms, more preferably 1 to 6 carbon atoms, and a cyclohexane having 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms. It shall be selected from any one or more of alkyl groups.

  More specifically, poly (N-methylacrylamide), poly (N-ethylacrylamide), poly (N-cyclopropylacrylamide), poly (N-isopropylacrylamide), poly (Nn-propylacrylamide), N-methyl-N-ethylacrylamide, N-methyl-N-isopropylacrylamide, N-methyl-Nn-propylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, poly (N-methylmethacrylamide) ), Poly (N-ethylmethacrylamide), poly (N-cyclopropylmethacrylamide), poly (N-isopropylmethacrylamide), poly (Nn-propylmethacrylamide), N-methyl-N-ethylmethacrylamide N-methyl-N-isopropylmeta Riruamido, N- methyl -N-n-propyl methacrylamide, N, N- dimethyl methacrylamide, N, N- diethyl methacrylamide, polyvinyl methyl ether and polyvinyl ether or the like can be used in the absorbent layer 16b.

  Further, not only the above-described polymer homopolymer, but also a copolymer obtained by combining two or more types of monomers constituting the polymer, or other types of monomers and monomers contained in the polymer described above. A combined copolymer may be used. In addition, any one of the above polymers may be used alone, or a plurality of types may be used in combination.

  Furthermore, in the above-mentioned example, the example in which the absorption layer 16b is a temperature-responsive polymer has been shown, but in addition, the absorption layer 16b has a resin that swells by absorbing hydraulic fluid and a predetermined phase transition temperature or higher. It is good also as composite resin which mixed two types of resin with resin which shrink | contracts and volume decreases. Even with such a composite resin, the same function as the above-described temperature-responsive polymer can be obtained.

  The absorption layer 16b is chemically bonded to the surface of the support layer 16a in order to prevent it from dissolving and disappearing in the working fluid 18. When a polymer material is used as the support layer 16a, the surface of the support layer 16a and the polymer constituting the absorption layer 16b are graft-bonded.

  As shown in FIG. 1B, FIG. 2A, and FIG. 2B, the evaporation unit 12 includes a heat block 20, an evaporation tube 21, and a wick 22.

  The heat block 20 is a metal plate that is filled with contents. The heat block 20 diffuses heat received from the outside throughout the heat block 20.

  A cylindrical evaporation tube 21 is accommodated in the center of the heat block 21. The evaporation pipe 21 is made of, for example, a copper pipe or the like, and a plurality of groove grooves (steam passages) 21 a extending in a direction parallel to the central axis of the evaporation pipe 21 are formed on the inner peripheral side thereof. These steam flow paths 21 a communicate with the steam pipe 13 via the steam converging part 23.

  The wick 22 is a tubular porous member whose end on the side of the steam pipe 13 is closed, and the outer peripheral surface of the wick 22 is in contact with the inner peripheral surface of the evaporation pipe 21 (excluding the steam channel 21a). 21. A hollow portion on the inner peripheral side of the wick 22 serves as a hydraulic fluid channel 22 a, and the hydraulic fluid channel 22 a communicates with the compensation chamber 11. The hydraulic fluid passage 22 a is separated from the vapor passage 21 a by the wick 22.

  As shown in FIG. 1A, the steam pipe 13 connects the evaporator 12 and the condenser pipe 14, and guides the steam generated in the evaporator pipe 21 of the evaporator 12 to the condenser pipe 14. The condenser tube 14 includes a heat sink (not shown), and heat is radiated by the heat sink to condense the vapor and generate the working liquid 18. The liquid pipe 15 connects the condenser pipe 14 and the compensation chamber 11, and guides the hydraulic fluid 18 generated by the condenser pipe 14 to the compensation chamber 11.

  As shown in FIG. 3, an electronic component 85 is joined to the heat block 20 of the present embodiment via thermal grease (not shown) or the like. One end of the auxiliary heat pipe 17 is joined to the portion of the compensation chamber 11 where the hydraulic fluid absorbing member 16 is provided. The other end of the auxiliary heat pipe 17 is thermally joined to the electronic component 85, and the auxiliary heat pipe 17 transmits the heat of the electronic component 85 to the working fluid absorbing member 16 in the compensation chamber 11.

  The hydraulic fluid absorbing member 16 can be produced as follows. Here, an example will be described in which a polypropylene nonwoven fabric is used as the support layer 16a, and poly-N-isopropylacrylamide is grafted to the surface of the support layer 16a as the temperature-responsive polymer of the absorption layer 16b.

  First, as the support layer 16a, for example, a polypropylene nonwoven fabric having an average pore diameter of about 10 μm is prepared. Next, the surface of the support layer 16a is irradiated with plasma in an argon atmosphere to generate active species on the surface of the support layer 16a. The method of generating active species on the surface of the support layer 16a may be performed by radiation irradiation, electron beam irradiation, or the like in addition to plasma irradiation.

  Thereafter, the support layer 16a is immersed in a degassed 3% N-isopropylacrylamide aqueous solution having a temperature of about 60 ° C. Thereby, N-isopropylacrylamide is polymerized on the support layer 16a using the active species on the surface of the support layer 16a as a starting point, and the absorption layer 16b grafted to the support layer 16a is formed.

  Next, the support layer 16a and the absorption layer 16b are taken out from the 3% N-isopropylacrylamide aqueous solution, washed with, for example, a cleaning solution in which water and methanol are mixed at a ratio of 1: 1, and vacuum dried. The hydraulic fluid absorbing member 16 of the present embodiment is completed by laminating a plurality of support layers 16a and absorbent layers 16b produced as described above.

  Instead of the method for generating active species on the surface of the support layer 16a described above, a functional group capable of reacting with the functional group by generating a reactive functional group by chemically treating the surface of the support layer 16a. A temperature-responsive polymer having In this case, the functional groups generated on the surface of the support layer 16a include carboxyl group, aldehyde group, amino group, imino group, sulfonic acid group, epoxy group, isocyanate group, acid chloride group, hydroxy group, thiol group, and disulfide. Groups and the like. Further, instead of performing chemical treatment on the support layer 16a, the support layer 16a may be formed of a polymer material having any of the functional groups listed above.

  In addition, the other structure of the loop type heat pipe 10 can be produced by a known method using a metal material such as copper, for example.

  Hereinafter, starting when the loop heat pipe 10 according to the present embodiment is in the top heat arrangement will be described. Here, FIGS. 4A and 4B are schematic diagrams showing changes in the temperature-responsive polymer. FIG. 5 is a cross-sectional view illustrating a state at the start of the compensation chamber and the evaporation unit of the loop heat pipe according to the embodiment. In FIG. 4, the symbol B indicates the polymer chain of the temperature-responsive polymer, and the symbol C indicates the molecule of the hydraulic fluid 18.

  As shown in FIGS. 1 (a) and 1 (b), when the operation of the loop heat pipe 10 is stopped with the top heat arrangement, the temperature of the loop heat pipe 10 decreases and the temperature at which the absorption layer 16b is formed. It becomes below the phase transition temperature of the responsive polymer. At this time, as shown in FIG. 4A, the acrylamide portion of the side chain of the temperature-responsive polymer absorbs water (the working fluid 18), the polymer chain extends, and the absorption layer 16b swells. Further, as shown in FIG. 1B, the hydraulic fluid absorbing member 16 of the present embodiment closes the gap between the support layers 16a when the absorbent layer 16b swells, and wicks 22 the space in the compensation chamber 11. This is divided into a region on the side and a region on the liquid tube 15 side. As a result, the working fluid 18 can be held in the compensation chamber 11 by preventing the working fluid 18 from moving when the operation of the loop heat pipe 10 is stopped.

  Next, when power is supplied to the electronic component (for example, CPU) 85, the electronic component 85 generates heat, and this heat is transmitted to the hydraulic fluid absorbing member 16 via the auxiliary heat pipe 17 and the evaporation unit 12. As a result, the working fluid absorbing member 16 is heated and reaches a temperature higher than the phase transition temperature of the absorbing layer 16b, and the absorbing layer 16b releases the liquid working fluid 18 and contracts as shown in FIG. 4B.

  The hydraulic fluid 18 released at this time is supplied to the wick 22 to wet the wick 22 as shown in FIG. Further, the gap between the support layers 16 a is opened by the contraction of the absorption layer 16 b, and the working fluid 18 held in the compensation chamber 11 is supplied to the wick 22. In this way, almost the entire wick 22 is wetted with the hydraulic fluid 18.

  Further, the heat of the electronic component 85 is transmitted from the outer periphery side of the wick 22 through the heat block 20 and the evaporation tube 21, and the working fluid 18 evaporates on the outer periphery side of the wick 22. At this time, since the holes of the wick 22 are blocked by the hydraulic fluid 18, the generated vapor cannot pass through the holes of the wick 22 and flow backward to the hydraulic fluid channel 22a. The concentration difference due to the evaporation of the working fluid on the outer peripheral side of the wick 22 becomes a driving force, the working fluid 18 is supplied from the working fluid flow path 22a side, and the circulation of the working fluid in the loop heat pipe 10 starts. 10 starts.

  Next, the operation after the start of starting of the loop heat pipe 10 will be described. FIG. 6A is a view showing a state in which the loop heat pipe according to the embodiment is operated in the top heat arrangement, and FIG. 6B is a diagram illustrating the compensation chamber and the evaporation unit in FIG. FIG.

  As shown in FIG. 6A, during the operation of the loop heat pipe 10, the working fluid 18 flows into the compensation chamber 11 through the liquid pipe 15. As shown in FIG. 6B, the hydraulic fluid 18 is temporarily stored in the compensation chamber 11. During the operation of the loop heat pipe 10, the temperature of the working fluid 18 is higher than the phase transition temperature of the working fluid absorbing member 16, so that the absorbing layer 16 b is contracted and a gap is generated between the support layers 16 a. For this reason, the hydraulic fluid 18 can move into the hydraulic fluid flow path 22a through the gap of the support layer 16a. During operation, since the gap between the support layers 16a is as large as several hundred μm to several mm, the hydraulic fluid absorbing member 16 can pass the hydraulic fluid 18 with a relatively small flow resistance.

  The hydraulic fluid 18 that has moved into the hydraulic fluid flow path 22 a is carried to the outer peripheral side of the wick 22 by the capillary force of the wick 22, and is evaporated via the heat block 20 to evaporate on the outer peripheral side of the wick 22. The steam generated on the outer peripheral side of the wick 22 is collected in the steam converging part 23 through the steam flow path 21 a and then flows out from the evaporation part 12. The steam that has flowed out of the evaporator 12 is guided to the condenser pipe 14 by the steam pipe 13, condensed in the condenser pipe 14, and returned to the working liquid 18. Thereafter, the hydraulic fluid 18 generated in the condenser pipe 14 is pushed up in the liquid pipe 15 by the pressure difference between the vapor channel 21 a and the hydraulic fluid channel 22 b and moves into the compensation chamber 11.

  As described above, the loop heat pipe 10 circulates the working fluid while repeating evaporation and condensation, thereby transporting the heat on the evaporation unit 12 side to the condenser tube 14 side.

  Note that the loop heat pipe 10 of the present embodiment has the top described with reference to FIG. 6, even in the bottom heat arrangement in which the evaporation section 12 is arranged in a lower state than the condenser pipe (condensing section) 14. It operates in the same manner as the heat placement operation.

  As described above, the loop heat pipe 10 according to the present embodiment absorbs moisture at a temperature lower than the phase transition temperature in the compensation chamber 11 and releases the water at a temperature higher than the phase transition temperature. A hydraulic fluid absorbing member 16 including (absorbing layer 16) and an auxiliary heat pipe 17 for heating the hydraulic fluid absorbing member 16 are provided. For this reason, even when the loop heat pipe 10 is in a top heat arrangement, the working fluid 18 can be released from the absorbing layer 16 at the start-up to wet the wick 22 and start circulation of the working fluid. . Further, when the loop heat pipe 10 is operated, the absorption layer 16 contracts, so that an increase in the flow resistance of the working fluid can be suppressed. For this reason, the loop heat pipe 10 of this embodiment is also excellent in heat transport characteristics.

  Hereinafter, an example in which the loop heat pipe 10 according to the present embodiment is mounted on an electronic device will be described. FIG. 7 is a perspective view illustrating a computer in which the loop heat pipe according to the embodiment is mounted.

  As shown in FIG. 7, an electronic device (computer) 80 includes an electronic component 85 having a large heat generation amount such as a CPU, a wiring board 81 on which the electronic component 85 is mounted, a cooling fan 82 for taking in outside air, and an auxiliary device. A hard disk drive 83 as a storage device and a power supply unit 84 are provided. The loop heat pipe 10 is mounted on the wiring board 81, and the capacitor tube 14 (and the heat sink) is disposed in the vicinity of the cooling fan 82. The evaporation unit 12 of the loop heat pipe 10 is joined to the upper surface of the electronic component 85 via thermal grease (not shown). Further, as shown in FIG. 3, the compensation chamber 11 and the electronic component 86 are thermally connected by an auxiliary heat pipe 17.

  As described above, since the electronic device 80 according to the present embodiment has the loop heat pipe 10 mounted thereon, for example, the electronic device 80 is arranged so that the direction indicated by the arrow Y1 in FIG. Even if it becomes top heat arrangement | positioning, it can cool. Furthermore, since the loop heat pipe 10 of the present embodiment has a high heat transport capability, efficient cooling is possible, and the air volume of the cooling fan 82 is suppressed to reduce the noise of the electronic device 80 and drive the cooling fan 82. Power consumption can be reduced.

  Regarding the above embodiment, the following additional notes are disclosed.

(Supplementary note 1) an evaporation unit that receives heat from outside and evaporates the working fluid;
A condensing part that radiates heat to the outside and condenses the vapor of the hydraulic fluid;
A compensation chamber for storing the hydraulic fluid to be supplied to the evaporation unit;
A steam pipe for guiding the vapor of the hydraulic fluid generated in the evaporation section to the condensation section;
A liquid pipe for guiding the hydraulic fluid condensed in the condensing unit to the compensation chamber;
A wick made of a porous material disposed in the steam pipe and separating a working fluid flow path communicating with the compensation chamber and a steam flow path communicating with the steam pipe;
A hydraulic fluid absorbing member that is disposed in the compensation chamber and absorbs and expands when the temperature is lower than a predetermined temperature, and contracts and releases the hydraulic fluid when the temperature is higher than the predetermined temperature;
A loop-type heat pipe characterized by comprising:

  (Supplementary note 2) The loop heat pipe according to supplementary note 1, wherein the hydraulic fluid absorbing member includes a temperature-responsive polymer.

  (Additional remark 3) The said hydraulic fluid absorption member has the structure where the support layer which consists of a material which is not melt | dissolved in the said hydraulic fluid, and the absorption layer which consists of the said temperature-responsive polymer chemically bonded to the said support layer surface were laminated | stacked two or more. The loop-type heat pipe according to Supplementary Note 2, wherein

  (Supplementary note 4) The supplementary note 1 further includes an auxiliary heat pipe having one end portion thermally joined to the heat generating component and the other end portion thermally joined to the compensation chamber. Loop type heat pipe.

  (Supplementary Note 5) When the hydraulic fluid absorbing member reaches a temperature lower than the phase transition temperature, the hydraulic fluid absorbing member absorbs the hydraulic fluid and expands, and the space in the compensation chamber is separated from the hydraulic fluid channel side region and the liquid pipe side. The loop type heat pipe according to any one of appendices 1 to 4, wherein the loop type heat pipe is divided into two regions.

  (Additional remark 6) The said hydraulic fluid is water, The said temperature-responsive polymer is poly N-substituted acrylamide, poly N-substituted methacrylamide, poly NN-disubstituted acrylamide, poly NN-disubstituted methacrylamide, and polyvinyl. The loop heat pipe according to appendix 2, which is made of any homopolymer of ether or a copolymer thereof.

  (Supplementary note 7) The loop heat pipe according to supplementary note 6, wherein the temperature-responsive polymer is made of poly-N-isopropylacrylamide.

  (Supplementary note 8) The loop heat pipe according to supplementary note 3, wherein the support layer is made of a polymer material, and the temperature-responsive polymer is graft-bonded to the support layer.

(Supplementary Note 9) An evaporation unit that receives heat from the outside and evaporates the working fluid;
A condensing part that radiates heat to the outside and condenses the vapor of the hydraulic fluid;
A compensation chamber for storing the hydraulic fluid to be supplied to the evaporation unit;
A steam pipe for guiding the vapor of the hydraulic fluid generated in the evaporation section to the condensation section;
A liquid pipe for guiding the hydraulic fluid condensed in the condensing unit to the compensation chamber;
A wick made of a porous material disposed in the steam pipe and separating a working fluid flow path communicating with the compensation chamber and a steam flow path communicating with the steam pipe;
A hydraulic fluid absorbing member that is disposed in the compensation chamber and absorbs and expands when the temperature is lower than a predetermined temperature, and contracts and releases the hydraulic fluid when the temperature is higher than the predetermined temperature;
An electronic device equipped with a loop heat pipe having
The electronic device is characterized in that the evaporation unit is thermally connected to an electronic component that generates heat.

  (Additional remark 10) The said condensation part is provided in the vicinity of the cooling fan, The electronic device of Additional remark 9 characterized by the above-mentioned.

  DESCRIPTION OF SYMBOLS 10 ... Loop type heat pipe, 11 ... Compensation chamber, 12 ... Evaporating part, 13 ... Steam pipe, 14 ... Condenser pipe (condensing part), 15 ... Liquid pipe, 16 ... Hydraulic fluid absorption member, 16a ... Support layer, 16b ... Absorbing layer, 17 ... auxiliary heat pipe, 18 ... working fluid, 20 ... heat block, 21 ... evaporating tube, 21a ... steam channel, 22 ... wick, 22a ... working fluid channel, 23 ... steam converging unit, 80 ... electron Equipment: 81 ... Wiring board, 82 ... Cooling fan, 83 ... Hard disk drive, 84 ... Power supply unit, 85 ... Electronic component.

Claims (6)

An evaporating section that receives heat from outside and evaporates the working fluid;
A condensing part that radiates heat to the outside and condenses the vapor of the hydraulic fluid;
A compensation chamber for storing the hydraulic fluid to be supplied to the evaporation unit;
A steam pipe for guiding the vapor of the hydraulic fluid generated in the evaporation section to the condensation section;
A liquid pipe for guiding the hydraulic fluid condensed in the condensing unit to the compensation chamber;
Wherein disposed in the evaporation section, a wick made of a porous material that separates the hydraulic fluid flow path and a steam flow path in communication with the steam pipe in communication with the compensation chamber,
A hydraulic fluid absorbing member that is disposed in the compensation chamber and absorbs and expands when the temperature is lower than a predetermined temperature, and contracts and releases the hydraulic fluid when the temperature is higher than the predetermined temperature;
A loop-type heat pipe characterized by comprising:   The loop type heat pipe according to claim 1, wherein the hydraulic fluid absorbing member includes a temperature-responsive polymer.   The hydraulic fluid absorbing member has a structure in which a plurality of support layers made of a material that does not dissolve in the hydraulic fluid and a plurality of absorption layers made of the temperature-responsive polymer chemically bonded to the surface of the support layer are laminated. The loop heat pipe according to claim 1.   The loop heat according to claim 1, further comprising an auxiliary heat pipe having one end thermally joined to the heat generating component and the other end thermally joined to the compensation chamber. pipe.   The working fluid is water, and the temperature-responsive polymer is any one of poly N-substituted acrylamide, poly N-substituted methacrylamide, polyNN-disubstituted acrylamide, polyNN-disubstituted methacrylamide, and polyvinyl ether. The loop type heat pipe according to claim 2, wherein the loop type heat pipe is made of a homopolymer of the above or a copolymer thereof. An evaporating section that receives heat from outside and evaporates the working fluid;
A condensing part that radiates heat to the outside and condenses the vapor of the hydraulic fluid;
A compensation chamber for storing the hydraulic fluid to be supplied to the evaporation unit;
A steam pipe for guiding the vapor of the hydraulic fluid generated in the evaporation section to the condensation section;
A liquid pipe for guiding the hydraulic fluid condensed in the condensing unit to the compensation chamber;
Wherein disposed in the evaporation section, a wick made of a porous material that separates the hydraulic fluid flow path and a steam flow path in communication with the steam pipe in communication with the compensation chamber,
A hydraulic fluid absorbing member that is disposed in the compensation chamber and absorbs and expands when the temperature is lower than a predetermined temperature, and contracts and releases the hydraulic fluid when the temperature is higher than the predetermined temperature;
An electronic device equipped with a loop heat pipe having
The electronic device is characterized in that the evaporation unit is thermally connected to an electronic component that generates heat.

Images