JP2012047103A - Actuator and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator that produces drive force by phase-change between liquid and gas, and has characteristics less dependent on the attitude, and to provide an electronic device having the actuator.SOLUTION: The actuator 20 has a tubular cylinder 21, and a supporting member 22 inserted inside the cylinder 21 and movably supporting the cylinder 21 in a direction parallel to the center axis thereof. Between the cylinder 21 and the supporting member 22, as a driving medium 23, for example, chlorofluorocarbon is filled, and a liquid absorbing member 22a having many bores is provided at a tip of the supporting member 22. As heat is transmitted from a heating element to the driving medium 23 via the supporting member 22, the driving medium is phase-changed form liquid to gas, and the cylinder 21 is driven. As the liquefied driving medium 23 is absorbed to a liquid absorbing part 22a by capillarity, the actuator 20, even if arranged horizontally, exhibits characteristics almost the same as a case where it is arranged vertically.

Description

  The present invention relates to an actuator using a phase change of a substance and an electronic device including the actuator.

  Conventionally, an actuator has been proposed in which a liquid is sealed in a sealed space and a change in volume accompanying a phase change between the liquid and gas is used as a driving force. For example, an actuator has been proposed in which a liquid and a heating element are enclosed in a hollow elastic member, and a driving force is generated by changing the phase of the liquid to a gas by heat generated by the heating element.

  An actuator using such a phase change can be easily miniaturized, and is expected to be used for various devices such as portable electronic devices. Hereinafter, the substance that is sealed in the actuator and changes in phase between the liquid and the gas is referred to as a drive medium.

JP-A-5-248345 JP 2003-206909 A

  A conventional actuator using a phase change between a liquid and a gas changes its characteristics depending on its posture (tilt).

  Accordingly, it is an object of the present invention to provide an actuator that generates a driving force due to a phase change between a liquid and a gas and whose characteristics do not depend on the posture, and an electronic device including the actuator.

  According to one aspect, a cylindrical cylinder having one end closed and the other end opened, a support member inserted into the cylinder and movably supported, and the cylinder and the support member And a drive medium that changes phase between a liquid phase and a gas phase according to temperature. A liquid medium is provided on one of the front end surface of the support member and the closed surface of the cylinder. An actuator provided with a liquid absorbing portion for absorbing the driving medium is provided.

  In the actuator according to the above aspect, a liquid absorbing portion that absorbs the liquid driving medium is provided on one of the front end surface of the support member and the closed surface of the cylinder. Thereby, the change of the characteristic by the attitude | position (inclination) of an actuator is suppressed.

FIGS. 1A and 1B are cross-sectional views (schematic diagrams) for explaining an example of an actuator using a phase change between a liquid and a gas. FIGS. 2A and 2B are explanatory views for explaining the operation when the actuators of FIGS. 1A and 1B are horizontally arranged. FIGS. 3A and 3B are explanatory views for explaining the operation when the actuators of FIGS. 1A and 1B are arranged upside down. 4A and 4B are cross-sectional views (schematic diagrams) of the actuator according to the first embodiment. FIGS. 5A and 5B are explanatory diagrams for explaining the operation when the actuators according to the first embodiment are horizontally arranged. FIGS. 6A and 6B are explanatory diagrams illustrating an example in which the actuator according to the first embodiment is used in a server cooling system. FIGS. 7A and 7B are schematic views showing the operation of the shutter provided on the front side of the server housing. FIG. 8 is a diagram describing a chemical formula and a boiling point for each refrigerant number of Freon. FIGS. 9A and 9B are cross-sectional views (schematic diagrams) of the actuator according to the second embodiment. FIGS. 10A and 10B are explanatory views for explaining the operation when the actuators according to the second embodiment are horizontally arranged. FIGS. 11A and 11B are explanatory diagrams for explaining the operation when the actuator according to the second embodiment is arranged upside down. FIGS. 12A and 12B are schematic views (cross-sectional views) of the actuator of the first modification. FIGS. 13A and 13B are schematic views (cross-sectional views) of the actuator of the second modification. 14A and 14B are schematic views (cross-sectional views) of actuators according to other embodiments.

  Hereinafter, before describing the embodiment, a preliminary matter for facilitating understanding of the embodiment will be described.

  FIGS. 1A and 1B are cross-sectional views (schematic diagrams) for explaining an example of an actuator using a phase change between a liquid and a gas.

  The actuator 10 has a cylindrical cylinder 11 whose one end is closed and the other end is opened, and a columnar support which is inserted inside the cylinder 11 and movably supports the cylinder 11 in a direction parallel to the central axis. Member 12. Further, in the space between the support member 12 and the cylinder 11, for example, chlorofluorocarbon is sealed as the drive medium 13.

  Further, a lubricant (not shown) is filled between the peripheral surface of the support member 12 and the inner wall surface of the cylinder 11. With this lubricant, the airtightness of the space in the cylinder 11 is maintained, and the frictional resistance between the cylinder 11 and the support member 12 is reduced.

  In such an actuator 10, the support member 12 is thermally connected to a heating element such as a CPU (Central Processing Unit) in the electronic device, for example. Here, it is assumed that the actuator 10 is arranged with the central axis of the cylinder 11 vertical (parallel to the direction of gravity: hereinafter the same).

  When the heating element is not generating heat, the drive medium 13 is in a liquid state as shown in FIG. 1A, the volume of the space between the cylinder 11 and the support member 12 is small, and the actuator 10 is contracted. It becomes.

  When the heating element generates heat, the heat generated by the heating element is transmitted to the drive medium 13 via the support member 12. As a result, the drive medium 13 evaporates into a gas, and the volume expands. Then, due to the expansion of the volume of the drive medium 13, the cylinder 11 moves relative to the support member 12 as shown in FIG. 1B, and the actuator 10 is extended.

  By the way, when this actuator 10 is arranged horizontally (right angle to the direction of gravity: the same applies hereinafter) as shown in FIG. 2A, the drive medium 13 evaporates and the cylinder 11 moves, so that FIG. As described above, the contact area between the support member 12 and the liquid drive medium 13 changes (decreases). For this reason, even if the temperature of the support member 12 is the same, the evaporation speed of the driving medium 13 changes, and the characteristics of the actuator 10 (for example, the operating speed and the strength of the driving force) are different from the case where they are arranged vertically. End up.

  Further, when the actuator 10 is arranged upside down as shown in FIG. 3A, the support member 12 moves away from the liquid drive medium 13 as shown in FIG. End up. This makes it difficult for heat to be transferred from the support member 12 to the liquid drive medium 13, and the characteristics of the actuator 10 are significantly different from those shown in FIGS. 1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b). .

  In other words, the characteristics of the actuator 10 described above depend on its posture (tilt). For this reason, it is necessary to design the actuator in consideration of the posture, and the versatility is low.

  Hereinafter, embodiments will be described.

(First embodiment)
4A and 4B are cross-sectional views (schematic diagrams) of the actuator according to the first embodiment.

  The actuator 20 according to the present embodiment includes a cylindrical cylinder 21 whose one end is closed and the other end is opened, and is inserted inside the cylinder 21 to support the cylinder 21 so as to be movable in a direction parallel to the central axis. And a support member 22. The cylinder 21 is formed of, for example, stainless steel, an aluminum alloy, or a copper alloy, and the support member 22 is formed of an aluminum alloy, a copper alloy, or the like that has good thermal conductivity.

  A drive medium 23 is enclosed in a space between the cylinder 21 and the support member 22. In the present embodiment, chlorofluorocarbon (chlorofluorocarbon, hydrochlorofluorocarbon, hydrofluorocarbon or the like) is used as the drive medium 23. However, the drive medium 23 may be any medium that causes a phase change between a liquid and a gas in the temperature range during use, and a compound other than Freon may be used as the drive medium 23.

  A liquid absorbing portion 22 a is provided at the distal end portion of the support member 22. The liquid absorbing portion 22a is formed of, for example, a resin such as fluororesin, polyethylene, polypropylene, or polycarbonate, a metal such as titanium or stainless steel, or a ceramic such as silica, alumina, or titanium oxide. The liquid absorbing portion 22a is provided with a large number of small holes connected to each other. In addition, the liquid absorption part 22a should just absorb the liquid drive medium 23 by a capillary phenomenon so that it may mention later, and is not limited to the above-mentioned material and structure. However, it is important that the liquid absorbing portion 22 a is formed of a material that is chemically stable with respect to the driving medium 23.

  A lubricant (not shown) is filled between the peripheral surface of the support member 22 and the inner wall surface of the cylinder 21. With this lubricant, the airtightness of the space in the cylinder 21 is maintained, and the frictional resistance between the cylinder 21 and the support member 22 is reduced.

  Hereinafter, the operation of the actuator 20 of the present embodiment will be described.

  Here, it is assumed that the support member 22 is thermally connected to a heating element such as a CPU in the electronic device. Further, as shown in FIG. 4A, the center axis of the cylinder 21 is assumed to be arranged vertically (parallel to the direction of gravity).

  When the temperature of the support member 22 is low, that is, when the heating element is not generating heat, the drive medium 23 is in a liquid state, and the actuator 20 is contracted. In this case, the space between the cylinder 21 and the support member 22 is filled with the liquid driving medium 23, and the liquid driving medium 23 enters the liquid absorbing portion 22a.

  When the heating element generates heat, the heat of the heating element is transmitted to the liquid driving medium 23 via the support member 22. Thereby, the drive medium 23 evaporates to become a gas, and the volume expands. As the volume of the drive medium 23 expands, the cylinder 21 moves relative to the support member 22 as shown in FIG. 4B, and the actuator 20 extends.

  When the heat generation from the heating element stops and the temperature of the support member 22 decreases, the drive medium 23 becomes liquid and the volume is reduced. As a result, the cylinder 21 moves relative to the support member 22, and the actuator 20 returns to the contracted state as shown in FIG.

  It is assumed that the actuator 20 is disposed horizontally as shown in FIG. In this case, when the temperature of the support member 22 is low, the drive medium 23 is in a liquid state and the actuator 20 is in a contracted state. At this time, the space between the cylinder 21 and the support member 22 is filled with the liquid drive medium 23.

  When the heating element generates heat, the heat of the heating element is transmitted to the liquid driving medium 23 through the support member 22, and the driving medium 23 evaporates to become a gas, and the volume expands. Thereby, as shown in FIG. 4B, the cylinder 21 moves relative to the support member 22, and the actuator 20 extends.

  At this time, the liquid level of the drive medium 23 moves downward as it evaporates. However, while the liquid drive medium 23 is in contact with the liquid absorption part 22a, the liquid drive medium 23 becomes liquid absorption part by capillary action. 22a is absorbed. As a result, the reduction of the contact area between the support member 22 and the liquid drive medium 23 is suppressed, and substantially the same characteristics as in the case where the support members 22 are arranged vertically are obtained.

  The actuator 20 of the present embodiment expands and contracts using the phase change of the drive medium 23 due to a temperature change as a driving force, so that no power source is required. Further, the actuator 20 of the present embodiment has a simple structure, can be easily downsized, and has a low risk of failure.

  Furthermore, since the actuator 20 of the present embodiment is provided with a liquid absorbing portion 22a that absorbs the liquid drive medium 23 by capillary action, the support member material 22 and the liquid drive medium 23 are arranged even when arranged horizontally. It is almost the same as when the contact area is arranged vertically. For this reason, even if the actuator 20 according to the present embodiment is arranged horizontally, almost the same characteristics as those obtained when arranged vertically are obtained.

  The liquid absorbing portion 22a is preferably subjected to a hydrophilic treatment so that the driving medium 23 can be easily absorbed. As the hydrophilic treatment, there is a method of coating the surface of the liquid absorbing portion 22a with polyethylene glycol or polyvinyl alcohol.

  An example in which the actuator according to the present embodiment is used in a cooling system of a server (an example of an electronic device) will be described with reference to FIGS.

  A plurality of servers 31 are stored in the server rack 30 side by side in the height direction. Each server 31 is mounted with heat-generating components that generate heat during operation, such as a CPU 38, a memory, and a hard disk drive. The server 31 takes in indoor air from the front side (left side in FIG. 6B) and cools the heat-generating components, and discharges the hot air from the rear side (right side in FIG. 6B). To do.

  An exhaust passage 32 and a fan (blower) 33 are provided on the back side of the server rack 30, and the air discharged from the server 31 is discharged out of the server rack 30 through the exhaust passage 32 and the fan 33. Is done.

  FIGS. 7A and 7B are schematic views illustrating the operation of the shutter provided on the front side of the housing of the server 31. FIG. As shown in FIGS. 7A and 7B, a shutter 35 is provided on the front side of the server 31. The shutter 35 includes a fixed plate 35 a fixed to the housing of the server 31 and a movable plate 35 b that can move in the horizontal direction. Each of the fixed plate 35a and the movable plate 35b is provided with an opening (ventilation opening).

  A heat transfer plate 36 is disposed on the side (left side in the figure) of the shutter 35, and two actuators 20a and 20b are connected in parallel between the heat transfer plate 36 and the movable plate 35b. . These actuators 20a and 20b both have the structure shown in FIG.

  Here, as shown in FIG. 6B, the heat transfer plate 36 is assumed to be thermally connected to a CPU (heat generating component) 38 via a heat pipe 37. The support members 22 of the actuators 20a and 20b are fixed to the heat transfer plate 36, and the cylinder 23 is connected to the movable plate 35b.

  In the cooling system having such a structure, when the temperature of the CPU 38 is low, the temperature of the heat transfer plate 36 is also low, and the actuators 20a and 20b are contracted as shown in FIG. In this case, the overlapping width of the opening of the fixed plate 35a and the opening of the movable plate 35b is small, and the aperture ratio of the shutter 35 is in a preset minimum state. In this state, the amount of air introduced into the server 31 where the temperature of the CPU 38 is low decreases, and the amount of air introduced into the server 31 where the temperature of the CPU 38 is high correspondingly increases.

  When the temperature of the CPU 38 in the server 31 increases, the temperature of the heat transfer plate 36 also increases, the drive medium 23 in the actuators 20a and 20b evaporates, and the actuators 20a and 20b extend. As a result, as shown in FIG. 7B, the movable plate 35b moves in the lateral direction, the opening of the fixed plate 35a and the opening of the movable plate 35b are almost completely overlapped, and the shutter 35 is fully opened. A large amount of air is introduced into the housing of the server 31 to cool the CPU 38 and other heat generating components.

  Thus, by controlling the amount of air introduced into the server 31 using the actuators 20a and 20b, air is preferentially introduced into the server 31 where the temperature of the CPU 38 is high. Thereby, the server 31 in the rack 30 can be efficiently cooled, and the power consumption can be reduced.

  In the above example, the CPU 38 and the heat transfer plate 36 are thermally connected by the heat pipe 37. However, the current flowing in the CPU 38 is branched to heat the heater, and the actuators 20a and 20b are driven by the heat. You may do it.

  By the way, when the drive medium 23 enclosed in the actuators 20a and 20b is made of a single compound, the aperture ratio of the shutter 35 is minimized when the temperature of the heat transfer plate 36 is lower than the boiling point of the compound. When the temperature of the heat transfer plate 36 is higher than the boiling point of the compound, the aperture ratio of the shutter 35 is maximized. However, when a mixture of a plurality of compounds having different boiling points is used as the driving medium 23, the aperture ratio of the shutter 35 can be changed stepwise according to the temperature.

  FIG. 8 shows the chemical formula and boiling point for each refrigerant number of CFCs. For example, the aperture ratio of the shutter 35 can be changed stepwise in accordance with the temperature by appropriately mixing and using a plurality of chlorofluorocarbons shown in FIG.

(Second Embodiment)
FIGS. 9A and 9B are cross-sectional views (schematic diagrams) of the actuator according to the second embodiment.

  The actuator 40 according to this embodiment includes a cylindrical cylinder 41 whose one end is closed and the other end is open, and is inserted inside the cylinder 41 so as to be movable in a direction parallel to the central axis thereof. And a supporting member 42 to be used. The cylinder 41 is made of stainless steel, aluminum alloy, copper alloy, or the like, and the support member 42 is made of aluminum alloy or copper alloy. Hereinafter, for convenience of description, the closed surface on one end side of the cylinder 41 is referred to as a bottom surface.

  As in the first embodiment, a liquid absorbing portion 42a formed of resin, metal, or ceramic having a large number of holes connected to each other is provided at the distal end portion of the support member 42. In the present embodiment, a plurality of porous elastic members 45 are disposed along the inner wall surface of the cylinder 41 to connect the liquid absorbing portion 42 a and the bottom surface of the cylinder 41 in an elastic manner. Further, a drive medium 43 such as Freon is enclosed in the cylinder 41.

  The porous elastic member 45 is formed by folding a flexible sheet-like resin such as a fluororesin, polyethylene, polypropylene, or polycarbonate into a bellows shape. The porous elastic member 45 is provided with a large number of small holes connected to each other, like the liquid absorbing portion 42. Both ends of the porous elastic member 45 may be bonded to the liquid absorbing portion 42a and the bottom surface of the cylinder 41, or may be in contact with the liquid absorbing portion 42a and the bottom surface of the cylinder 41 by elastic force. In addition, you may give the hydrophilic process to the liquid absorption part 42a and the porous elastic member 45. FIG.

  A lubricant (not shown) is filled between the peripheral surface of the support member 42 and the inner wall surface of the cylinder 41. With this lubricant, the airtightness of the space in the cylinder 41 is maintained, and the frictional resistance between the cylinder 42 and the support member 42 is reduced.

  Hereinafter, the operation of the actuator 40 of the present embodiment will be described.

  Here, it is assumed that the support member 42 is thermally connected to a heating element such as a CPU in the electronic device. Further, as shown in FIG. 9A, the cylinder 41 has a central axis arranged vertically (parallel to the direction of gravity).

  When the temperature of the support member 42 is low, that is, when the heating element does not generate heat, the drive medium 43 is in a liquid state and the actuator 40 is contracted. Moreover, the porous elastic member 45 will be in the folded state. In this case, the space between the cylinder 41 and the support member 42 is filled with the liquid drive medium 43.

  When the heating element generates heat, the heat of the heating element is transmitted to the liquid driving medium 43 through the support member 42, and the driving medium 43 becomes a gas and the volume expands. As a result, as shown in FIG. 9B, the cylinder 41 moves relative to the support member 42, and the actuator 40 extends. As the actuator 40 extends, the porous elastic member 45 also extends.

  When the heat generation from the heating element stops and the temperature of the support member 42 decreases, the drive medium 43 becomes liquid and the volume is reduced. As a result, the cylinder 41 moves relative to the support member 42, and the actuator 40 returns to the contracted state as shown in FIG. As the actuator 40 contracts, the porous elastic member 45 returns to the folded state.

  It is assumed that the actuator 40 is disposed horizontally as shown in FIG. In this case, when the temperature of the support member 42 is low, the drive medium 43 is in a liquid state, and the actuator 40 is contracted. At this time, the space between the cylinder 41 and the support member 42 is filled with the liquid drive medium 43.

  When the heating element generates heat, the heat of the heating element is transmitted to the drive medium 43 via the support member 42. Then, the drive medium 43 evaporates to become gas, and the volume expands. Accordingly, as shown in FIG. 10B, the cylinder 41 moves relative to the support member 42, and the actuator 40 extends. As the actuator 40 extends, the porous elastic member 45 also extends.

  At this time, the liquid level of the drive medium 43 moves downward along with evaporation, but while the liquid drive medium 43 is in contact with the liquid absorbing portion 42a and the porous elastic member 45, the liquid drive medium 43 is It is absorbed by the liquid absorption part 42a and the porous elastic member 45 by capillary action. As a result, the reduction in the contact area between the support member 42 and the drive medium 43 is suppressed, and substantially the same characteristics as when arranged vertically are obtained.

  The actuator 40 is arranged in an inverted state as shown in FIG. In this case, when the temperature of the support member 22 is low, the drive medium 43 is in a liquid state and the actuator 40 is in a contracted state. At this time, the space between the cylinder 41 and the support member 42 is filled with the liquid drive medium 43.

  When the heating element generates heat, the heat of the heating element is transmitted to the liquid driving medium 43 via the support member 42. And the drive medium 43 becomes gas and a volume expand | swells. As a result, as shown in FIG. 11B, the cylinder 41 moves relative to the support member 42 and the actuator 40 extends. As the actuator 40 extends, the porous elastic member 45 also extends.

  At this time, as the actuator 40 extends, the support member 42 moves away from the liquid surface of the drive medium 43 as shown in FIG. However, in this embodiment, since the porous elastic member 45 is disposed between the support member 42 and the bottom surface of the cylinder 41 so as to expand and contract, the liquid drive medium 43 is absorbed by the porous elastic member 45 by capillary action. Then, it is further absorbed by the liquid absorption part 42a. Therefore, when the liquid absorbing portion 42a is maintained in a state where it is filled with the liquid driving medium 43 and the contact area between the support member 42 and the liquid driving medium 43 is arranged vertically (FIGS. 9A and 9B). It is almost the same as b). For this reason, even if the actuator 40 according to the present embodiment is arranged upside down, almost the same characteristics as those obtained when arranged vertically are obtained.

  In the present embodiment, chlorofluorocarbon is used as the drive medium 43. Fluorocarbon generally has a low surface tension, for example, the surface tension of water is about 0.0728 N / m, whereas the surface tension of HFC-43-10mee is as low as about 0.0141 N / m. The capillary force (height rising height) h (m) of HFC-43-10mee can be calculated by the following equation (1), where r is the radius of the hole and 20 ° is the contact angle.

h≈1.71 × 10 ⁻⁶ / r (1)
From this equation (1), when the pore diameter of the liquid absorbing portion 42a is smaller than the pore diameter of the porous elastic member 45, the liquid absorbing ability of the liquid absorbing portion 42a becomes larger than the liquid absorbing ability of the porous elastic member 45. I understand that.

  That is, when the pore diameter of the liquid absorbing portion 42a is smaller than the pore diameter of the porous elastic member 45, the driving medium 43 absorbed by the porous elastic member 45 is easily moved to the liquid absorbing portion 42a. For this reason, it is preferable that the hole diameter of the liquid absorption part 42a is made smaller than the hole diameter of the porous elastic member 45. For example, when the maximum movement amount of the cylinder 41 is about 10 cm, the hole radius of the liquid absorbing portion 42a may be 10 μm or less, and the hole radius of the porous elastic member 45 may be 10 μm to 20 μm.

(Modification 1)
12A and 12B are schematic views (cross-sectional views) of an actuator according to the first modification. 12 (a) and 12 (b), the same components as those in FIGS. 11 (a) and 11 (b) are denoted by the same reference numerals, and detailed description thereof is omitted.

  The actuator 50 of the first modification has a curved shape in which the bottom surface of the cylinder 51 protrudes inward. Therefore, the liquid drive medium 43 is arranged in an inverted state as shown in FIGS. 12A and 12B, and the liquid drive medium 43 gathers at the edge of the bottom surface of the cylinder 51 even if the liquid drive medium 43 is reduced by evaporation. The porous elastic member 45 is efficiently absorbed.

  Thereby, the actuator 50 of the modified example 1 has an advantage that the characteristics are less likely to change compared to the actuator 20 of FIGS. 11A and 11B even when the amount of the liquid drive medium 43 is reduced.

(Modification 2)
FIGS. 13A and 13B are sectional views of the actuator of the second modification. 13 (a) and 13 (b), the same components as those in FIGS. 11 (a) and 11 (b) are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the actuator 52 of the second modification, a water repellent treatment is applied to the central portion (portion indicated by an arrow A in FIGS. 13A and 13B) of the bottom surface of the cylinder 53. As the water repellent treatment, there is a method such as coating with a fluororesin. When the actuator 51 of the second modification is placed upside down, the liquid drive medium 43 gathers at the edge of the bottom surface of the cylinder 53 even if the liquid drive medium 43 decreases due to evaporation, as in the first modification. The porous elastic member 45 is efficiently absorbed. In this case, it is preferable to apply a hydrophilic treatment to the edge of the bottom surface of the cylinder 53.

(Other embodiments)
In both the first and second embodiments, heat is transmitted from the heat source to the support members 22 and 42, and the liquid absorbing portions 22 a and 42 a are disposed at the tip portions of the support members 22 and 42. However, heat may be transferred from the heat source to the cylinders 21 and 41. In this case, for example, as illustrated in FIGS. 14A and 14B, the liquid absorbing portion 41 a may be disposed on the bottom surface side of the cylinder 41.

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

(Supplementary note 1) A cylindrical cylinder with one end closed and the other end open;
A support member inserted into the cylinder and movably supporting the cylinder;
A drive medium enclosed between the cylinder and the support member and having a phase change between a liquid phase and a gas phase according to temperature;
An actuator characterized in that a liquid absorbing portion that absorbs the liquid driving medium is provided on one of a front end surface of the support member and a closed surface of the cylinder.

  (Additional remark 2) The said liquid absorption part absorbs the said liquid drive medium by a capillary phenomenon, The actuator of Additional remark 1 characterized by the above-mentioned.

  (Supplementary note 3) The supplementary note 1 or 2, wherein the liquid drive medium is formed so as to be able to absorb, and has a stretchable member that expands and contracts while being in contact with the liquid absorbing portion and the closed surface of the cylinder. Actuator.

  (Additional remark 4) The said expansion-contraction member is formed by folding a sheet-like member, The actuator of Additional remark 3 characterized by the above-mentioned.

  (Additional remark 5) The liquid absorption capability of the said liquid absorption part is higher than the liquid absorption capability of the said expansion-contraction member, The actuator of Additional remark 3 characterized by the above-mentioned.

  (Supplementary note 6) The actuator according to supplementary note 3, wherein a hole diameter of the liquid absorbing portion is smaller than a hole diameter of the expandable member.

  (Supplementary note 7) The actuator according to any one of supplementary notes 1 to 3, wherein the driving medium includes a plurality of compounds having different boiling points.

  (Appendix 8) The actuator according to any one of appendices 1 to 3, wherein a surface on the closing side of the cylinder is curved inward.

(Supplementary Note 9) Heat-generating parts,
An actuator to which heat generated from the heat generating component is transmitted;
A drive unit driven by the actuator,
The actuator is
A cylindrical cylinder closed at one end and opened at the other end;
A support member inserted into the cylinder and movably supporting the cylinder;
A drive medium enclosed between the cylinder and the support member and changing phase between a liquid phase and a gas phase according to temperature; Any one of the electronic devices is provided with a liquid absorbing portion that absorbs the liquid driving medium.

  10, 20, 20a, 20b, 40, 50, 52 ... Actuator, 11, 21, 41, 51, 53 ... Cylinder, 12, 22, 42 ... Support member, 13, 23, 43 ... Drive medium, 22a, 41a, 42a ... Liquid absorber, 30 ... Server rack, 31 ... Server, 32 ... Exhaust flow path, 33 ... Fan, 35 ... Shutter, 35a ... Fixed plate, 35b ... Movable plate, 36 ... Heat transfer plate, 37 ... Heat pipe, 38 ... CPU, 45 ... porous elastic member.

Claims (6)

A cylindrical cylinder closed at one end and opened at the other end;
A support member inserted into the cylinder and movably supporting the cylinder;
A drive medium enclosed between the cylinder and the support member and having a phase change between a liquid phase and a gas phase according to temperature;
An actuator characterized in that a liquid absorbing portion that absorbs the liquid driving medium is provided on one of a front end surface of the support member and a closed surface of the cylinder.   The actuator according to claim 1, wherein the liquid absorption unit absorbs the liquid driving medium by a capillary phenomenon.   3. The actuator according to claim 1, further comprising an expansion / contraction member formed so as to be able to absorb the liquid driving medium and extending and contracting while being in contact with the liquid absorption portion and the closed surface of the cylinder. .   4. The actuator according to claim 3, wherein a liquid absorption capacity of the liquid absorption section is higher than a liquid absorption capacity of the expansion and contraction member.   The actuator according to claim 3, wherein a hole diameter of the liquid absorbing portion is smaller than a hole diameter of the expandable member. Heat-generating parts,
An actuator to which heat generated from the heat generating component is transmitted;
A drive unit driven by the actuator,
The actuator is
A cylindrical cylinder closed at one end and opened at the other end;
A support member inserted into the cylinder and movably supporting the cylinder;
A drive medium enclosed between the cylinder and the support member and changing phase between a liquid phase and a gas phase according to temperature; Any one of the electronic devices is provided with a liquid absorbing portion that absorbs the liquid driving medium.

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