JP2017072280A - heat pipe - Google Patents

Abstract

[PROBLEMS] Even if a heat pipe is installed and used in a state in which water as a working fluid is stored in a container, volume expansion due to freezing of the working fluid, particularly, freezing of water when the heat pipe is not operating. Provided is a heat pipe capable of preventing a container from being broken against volume expansion. A heat pipe having a cylindrical container and water sealed in the container, wherein the water is thermally connected to the container on at least one end surface inside the container. Heat pipe with a heat transfer section with higher thermal conductivity than that of the heat pipe. [Selection diagram] Fig. 1

Description

  The present invention relates to a heat pipe that can prevent destruction of a container due to freezing of a working fluid even when used in, for example, a cold region.

  Electronic parts such as semiconductor elements mounted on electric / electronic devices have increased in calorific value due to high-density mounting accompanying higher functionality, and in recent years, cooling has become more important. A heat pipe may be used as a cooling method for electronic components.

  Conventionally, a heat pipe is composed of a metal container in which water is enclosed under reduced pressure as a working fluid. Here, for example, when the heat pipe is installed in a state parallel to or substantially parallel to the direction of gravity, the working fluid is stored in the lower part of the heat pipe by gravity. When the ambient temperature drops below the freezing point of the working fluid in this state, the stored liquid-phase working fluid freezes from the contact portion with the container and the liquid surface side, and then the inside of the stored liquid-phase working fluid. Freezing progresses to the side. When the inside of the liquid-phase working fluid freezes and expands in volume, the stress generated by the volume expansion goes to the container because the liquid surface is solidified. According to such a principle, when the heat pipe is used in a cold region, depending on the posture in which the heat pipe is used, the hydraulic fluid stored in the container may expand in volume due to freezing and destroy the container. .

  Therefore, it has been proposed to insert a rubber having excellent cold resistance into the container as a buffer material to absorb the volume expansion of the working fluid by deformation of the buffer material to prevent the container from being destroyed (Patent Document 1). . However, in the deformation of the cushioning material of Patent Document 1, the cushioning material is hardened due to deterioration over time, excessive decrease in temperature, or the like, and may not absorb the volume expansion due to freezing of the working fluid, leading to destruction of the container. There was a problem.

JP 58-73563 A

  In view of the above circumstances, the object of the present invention is to expand the volume due to freezing of the working fluid, in particular, the heat pipe operates even when the heat pipe is installed and used in a state where water as the working fluid is stored in the container. An object of the present invention is to provide a heat pipe capable of preventing destruction of a container against volume expansion due to freezing of water in a state where it is not.

  An aspect of the present invention is a heat pipe having a cylindrical container and water sealed in the container, and is thermally connected to the container on at least one end face portion inside the container. It is a heat pipe provided with a heat transfer part having a higher thermal conductivity than water.

  In the above aspect, since the heat transfer part having a higher thermal conductivity than water (working fluid), which is thermally connected to the container, is provided on the end face part inside the container, from the vicinity of the heat transfer part, that is, It freezes from the inside of the liquid phase water (working fluid) stored in one end surface part. For this reason, when the water which remains inside freezes, volume expansion can be performed, and destruction of the container due to the stress applied to the container can be prevented.

  An aspect of the present invention is a heat pipe in which the heat transfer unit is provided in a state of being attached to one end surface of the container.

  In the said aspect, the said heat-transfer part is integrated with the one end surface part of the said container.

  The aspect of this invention is the convex part in which the said heat-transfer part was convexly formed in the wall surface of the one end surface part of the said container toward the direction of the other end surface part facing the said one end surface part. It is a heat pipe.

  In the above aspect, the heat transfer section is a part where the wall surface at one end surface portion of the container is formed in a convex shape toward the other end surface portion facing the one end surface portion. The water (working fluid) can be frozen more reliably from the inside.

  An aspect of the present invention is a heat pipe in which a top portion of the heat transfer portion is 1/2 or more of a depth of a liquid pool portion in which the water is stored and is on the other end surface portion side facing the one end surface portion. is there.

  In the present invention, the “liquid reservoir” means a portion where a liquid-phase working fluid is stored in a state where the heat pipe is not operating. In the present invention, “water” means pure water containing inevitable impurities and does not contain additives for preventing freezing.

  An aspect of the present invention is a heat pipe in which a reinforcing member having a higher thermal conductivity than the water is fitted to the outer surface of the convex portion outside the container.

  An aspect of the present invention is a heat pipe in which one end surface portion on which the convex portion is formed has a tapered portion.

  An aspect of the present invention is a heat pipe in which the tapered portion in the container is covered with a fluorine-based resin.

  An aspect of the present invention is a heat pipe in which a heat-shrinkable tube is wound around the outer surface of the tapered portion.

  According to the aspect of the present invention, the liquid phase water (working fluid) stored in one end portion is contacted with the side surface portion of the container and the liquid surface side by the heat transfer portion provided in the one end surface portion. As the volume of water expands due to freezing of liquid phase water, especially when the heat pipe is not in operation, the volume of water expands due to freezing of the liquid phase water. As a result, stress due to volume expansion on the container can be reduced. Thus, since the stress due to volume expansion to the container can be reduced, even in a cold district or the like, even if the container is installed and used in a state where water as a working fluid is stored, the container can be prevented from being broken.

  According to the aspect of the present invention, the position of the top portion of the heat transfer section is 1/2 or more of the depth of the liquid storage section in which the water is stored, and is on the other end face side, so that it is more than the liquid level side. From the inside of the stored liquid phase water, it can be frozen more reliably first. For this reason, the destruction of the container due to the volume expansion when the water inside the liquid reservoir is frozen can be more reliably prevented by freezing the outer periphery of the liquid reservoir (the contact portion and the liquid surface with the container) later. Can do.

  According to the aspect of the present invention, the reinforcing member having higher thermal conductivity than water is fitted to the outer surface of the convex portion, so that the mechanical end portion of the container is maintained while maintaining good thermal conductivity. Strength can be improved.

  According to the aspect of the present invention, the one end surface portion on which the convex portion is formed has a tapered portion, so that even if water freezes at one end surface portion of the container, along the tapered shape, Since the frozen water moves, the stress applied to the container can be reduced.

  According to the aspect of the present invention, the fluororesin is coated on the tapered portion, and / or the heat-shrinkable tube is wound around the outer surface of the tapered portion, so that the water frozen at the container end surface portion is Since it moves more smoothly along the tapered shape, the stress applied to the container can be reduced.

It is explanatory drawing by the side of the condensation part of the heat pipe which concerns on the example of 1st Embodiment of this invention. (A) A figure is explanatory drawing by the side of the condensation part of the heat pipe which concerns on 2nd Example of this invention, (b) figure is explanatory drawing of the reinforcement member attached to the condensation part side. It is explanatory drawing by the side of the condensation part of the heat pipe which concerns on the 3rd Example of this invention.

  The heat pipe according to the first embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the heat pipe 1 according to the first embodiment includes a container 10 made of a cylindrical tube material, a working fluid 11 enclosed in the container 10, and a wick provided on the inner surface of the container 10. (Not shown). The container 10 has a circular cross-sectional shape in the radial direction.

  Furthermore, a heat transfer portion having a higher thermal conductivity than the working fluid 11 is provided on the end surface portion 12 on the condensing portion side which is one end surface portion inside the container 10. In the heat pipe 1, a plurality (5 in FIG. 1) of rod-like bodies 13 are erected at the central portion of the end surface portion 12 on the condensing portion side as heat transfer portions. The rod-like body 13 is thermally connected to the end surface portion 12 on the condensation portion side of the container 10 and is fixed by attaching the end portion of the rod-like body 13 serving as the heat transfer portion to the end surface portion 12 on the condensation portion side. Has been. Moreover, since the rod-shaped body 13 is standingly arranged in the center part of the end surface part 12 by the side of a condensation part, it has become the aspect which is not contacting the side part 15 of the container 10. FIG.

  Although the installation interval of the rod-shaped bodies 13 is not particularly limited, in the heat pipe 1, the five rod-shaped bodies 13 are arranged at equal intervals in the radial direction of the container 10. Moreover, the attachment method to the end surface part 12 by the side of the condensation part of the rod-shaped body 13 is not specifically limited, For example, welding, soldering, etc. can be mentioned.

  In FIG. 1, the heat pipe 1 is installed in a position parallel to the gravity direction at a position where the evaporation section (not shown) is higher than the condensation section 16 (hereinafter, sometimes referred to as “top heat”). ing. As a result, the liquid-phase working fluid 11 is most easily stored in the condensing unit 16. The stored liquid-phase working fluid 11 becomes a maximum amount when the heat pipe 1 is not in operation, and the liquid reservoir 14 of the heat pipe 1 is filled with the liquid-phase working fluid 11. In the heat pipe 1, the position of the top portion of the rod-like body 13 is ½ or more of the depth of the liquid reservoir portion 14, the other end surface portion (end surface portion on the evaporation portion side) side facing the end surface portion 12 on the condensation portion side. It is. In FIG. 1, the position of the top portion of the rod-shaped body 13 is closer to the end surface portion 12 on the condensing portion side than the liquid surface of the liquid reservoir portion 14. Therefore, when the heat pipe 1 is installed in a direction parallel to the direction of gravity in the top heat and is not in operation, the top of the rod-like body 13 is the liquid phase working fluid 11 stored in the liquid reservoir 14. More than 1/2 of the depth, the liquid phase working fluid 11 stored in the liquid reservoir 14 is positioned closer to the end surface 12 on the condensing part side than the liquid surface of the liquid phase working fluid 11.

  Examples of the material of the container 10 include copper, a copper alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, and stainless steel. In addition, the working fluid to be sealed in the container 10 can be appropriately selected according to the compatibility with the material of the container 10, but water is used in the heat pipe 1. Furthermore, the rod-shaped body 13 provided as the heat transfer part is not particularly limited as long as it has a higher thermal conductivity than the working fluid 11. For example, the same material as the material of the container 10 may be used. Specific examples of the material include copper, copper alloy, aluminum, and aluminum alloy.

  The liquid-phase working fluid 11 stored in the end portion on the condensing unit 16 side by the rod-shaped body 13 is closer to the inside (that is, the rod-shaped body 13 that is the heat transfer unit) than the contact side and the liquid surface side with the side surface portion 15. As the frozen portion is formed from the contact portion and the vicinity of the rod-shaped body 13), even if the volume expansion due to freezing of the liquid-phase working fluid 11 occurs, the stress due to the volume expansion can be released from the liquid surface side. The stress due to the volume expansion on the container 10 can be reduced. Since the stress due to freezing of the liquid-phase working fluid 11 to the container 10 can be reduced, even if the working fluid 11 is installed and used in a cold region or the like in a state where the working fluid 11 is stored, the container 10 can be prevented from being broken. . Further, the position of the top of the rod-shaped body 13 is ½ or more of the depth of the liquid reservoir 14 where the liquid-phase working fluid 11 is stored, and the end of the condenser 16 side. From the inside of the liquid-phase working fluid 11 stored in the container, it can be more reliably frozen.

  Next, a heat pipe according to a second embodiment of the present invention will be described with reference to the drawings. In addition, about the same component as the heat pipe which concerns on 1st Embodiment, it demonstrates using the same code | symbol.

  As shown to Fig.2 (a), in the heat pipe 2 which concerns on 2nd Embodiment, it replaces with the heat-transfer part of a rod-shaped body, and is a convex part in the center part of the end surface part 12 by the side of a condensation part as a heat-transfer part. 23 is provided. The convex part 23 is formed by plastic deformation of the wall surface of the end face part 12 on the condensing part side in a convex manner in the direction of the other end face part (end face part on the evaporation part side) of the container 10. is there. The convex part 23 is thermally connected to the condensing part 16 of the container 10 because a part of the end surface part 12 on the condensing part side of the container 10 is plastically deformed into a convex shape.

  Moreover, since the convex part 23 is a thing by which the center part of the end surface part 12 by the side of a condensation part was plastically deformed, it has become the aspect which is not contacting the side part 15 inside the container 10. FIG. In the heat pipe 2, like the heat pipe 1 according to the first embodiment, the position of the top portion of the convex portion 23 is ½ or more of the depth of the liquid reservoir portion 14 and faces the end surface portion 12 on the condensing portion side. This is the other end surface portion (end surface portion on the evaporation portion side) side. Further, in FIG. 2A, the position of the top portion of the convex portion 23 is closer to the end surface portion 12 side on the condensing portion side than the liquid surface of the liquid reservoir portion 14. The number of protrusions 23 is not particularly limited, and may be one or more, but in the heat pipe 2, one protrusion 23 is provided.

  Furthermore, as shown in FIG. 2 (b), the outer surface side of the convex portion 23 which is the outside of the container 10, that is, the end surface portion 12 on the condensing portion side formed by providing the convex portion 23 as necessary. A reinforcing member 27 made of a material having a higher thermal conductivity than the working fluid 11 may be attached to the gap 29. In the heat pipe 2, the reinforcing member 27 has a protruding portion 28 corresponding to the shape and size of the outer surface side of the convex portion 23, that is, the shape and size of the gap 29, and the protruding portion 28 is fitted into the gap 29. Thus, the reinforcing member 27 is attached to the gap 29.

  The material of the reinforcing member 27 is not particularly limited as long as it has a higher thermal conductivity than that of the working fluid 11. For example, the same material as the material of the container 10 may be used. Examples thereof include copper, a copper alloy, aluminum, and an aluminum alloy. In the heat pipe 2, water is used as the working fluid 11.

  Even in the convex portion 23, the liquid-phase working fluid 11 stored at the end on the condensing unit 16 side is closer to the inside (that is, the convex portion 23 serving as the heat transfer unit) than the contact side and the liquid surface side with the side surface portion 15. Since the frozen portion is formed from the vicinity of the contact portion and the convex portion 23), even if the volume expansion due to freezing of the liquid-phase working fluid 11 occurs, the stress due to the volume expansion can be released from the liquid surface side. The stress due to the volume expansion on the container 10 can be reduced. Furthermore, the position of the top part of the convex part 23 is 1/2 or more of the depth of the liquid reservoir part 14 where the liquid-phase working fluid 11 is stored, and the end part on the side of the condensing part 16 side. From the inside of the liquid-phase working fluid 11 stored in the container, it can be more reliably frozen.

  Further, the reinforcing member 27 having a higher thermal conductivity than that of the working fluid 11 is attached to the air gap 29, so that the good thermal conductivity between the condensing unit 16 and the heat dissipating means is maintained, and the end of the condensing unit 16 side. The mechanical strength of can be improved.

  Next, a heat pipe according to a third embodiment of the present invention will be described with reference to the drawings. In addition, about the same component as the heat pipe which concerns on the 1st, 2nd embodiment, it demonstrates using the same code | symbol.

  As shown in FIG. 3, in the heat pipe 3 according to the third embodiment, the end surface portion 12 on the condensing portion side where the convex portion 23 is formed has a tapered portion 37. The tapered portion 37 is formed by reducing the diameter of the condensing part 16 of the container 10 toward the front end side of the condensing part 16 and increasing the width of the convex part 23 toward the front end side of the condensing part 16. The part where the diameter of the container 10 is reduced is not particularly limited, but in the heat pipe 3, the diameter of the container 10 is reduced from a position corresponding to the top of the convex part 23.

  Even in the aspect in which the end surface portion 12 on the condensing portion side where the convex portion 23 is formed has the tapered portion 37, the water that is the liquid phase working fluid 11 stored in the end portion on the condensing portion 16 side is the side surface portion 15. Since the frozen part is formed from the inside (that is, the contact part with the convex part 23 which is a heat transfer part and the vicinity of the convex part 23) rather than the contact side and the liquid surface side of the liquid, the liquid phase working fluid 11 is frozen. Even if the volume expansion due to is caused, the stress due to the volume expansion can be released from the liquid surface side, and as a result, the stress due to the volume expansion on the container 10 can be reduced.

  Further, the condensing part 16 of the container 10 has the tapered part 37, so that even if the liquid-phase working fluid 11 is frozen at the end surface part 12 on the condensing part side of the container 10, it follows the tapered part 37. Since the frozen working fluid 11 moves, the stress applied to the container 10 can be reduced.

  Moreover, as shown in FIG. 3, the fluorine-type resin 38, such as PTFE, may be coat | covered at the taper-shaped site | part 37 inside the container 10 as needed. Since the frozen working fluid 11 moves more smoothly along the tapered portion 37 by covering the tapered portion 37 with the fluororesin 38, the stress applied to the container 10 can be more reliably reduced. .

  Next, an example of how to use the heat pipe of the present invention will be described. Since the heat pipe of the present invention can prevent the container from being destroyed by freezing of the working fluid even in the top heat in a cold region, the heat pipe is used for cooling a heating element mounted on a cold region specification automobile, for example. be able to.

  Next, another embodiment of the heat pipe of the present invention will be described. In the heat pipe according to the first embodiment, a rod-like body is used as the heat transfer section, but the shape of the heat transfer section is not particularly limited, and may be, for example, a plate-like body or a spherical body. Further, in the heat pipe according to the first embodiment, the position of the top portion of the heat transfer section is 1/2 or more of the depth of the liquid reservoir, and is closer to the end face on the condensing part side than the liquid level of the liquid reservoir. However, it may be a position lower than the liquid level of the liquid-phase working fluid stored in the liquid reservoir, and may be less than ½ of the depth of the liquid reservoir. Moreover, in the heat pipe according to the first embodiment, the end of the heat transfer unit was attached to the end surface on the condensing unit side, but instead, the heat transfer unit on the end surface on the condensing unit side, It may be a mode of being mounted without being fixed. Moreover, in each said embodiment, although the heat-transfer part was provided in the end surface part by the side of a condensation part, you may provide in the end surface part by the side of an evaporation part further as needed.

  In the heat pipe according to the third embodiment, the fluororesin is coated on the tapered portion inside the container. Instead of or in addition to this, the outer surface of the tapered portion is subjected to heat shrinkage. A tube may be wound. Since the heat-shrinkable tube wound around the outer surface of the taper-shaped part heat-shrinks and deflects the taper-shaped part of the container, the frozen working fluid moves more smoothly along the taper-shaped part. The stress applied to the container can be reduced more reliably.

  Since the heat pipe of the present invention can prevent the destruction of the container due to freezing of the working fluid, it has a high utility value for cooling a heating element mounted on a device used in a cold region.

1, 2, 3 Heat pipe 10 Container 11 Working fluid 12 Condensing part side end face part 13 Rod-like body 14 Liquid reservoir part 23 Convex part 27 Reinforcement member 37 Tapered part

Claims (8)

  A heat pipe having a cylindrical container and water enclosed in the container, wherein the heat pipe is thermally connected to the container at least at one end surface inside the container and is more thermally conductive than the water. A heat pipe with a high rate heat transfer section.   The heat pipe according to claim 1, wherein the heat transfer section is provided in a state of being attached to one end face of the container.   The said heat-transfer part is a convex part formed in the wall surface of the one end surface part of the said container in the convex shape toward the direction of the other end surface part facing the said one end surface part. heat pipe.   The top part of the said heat-transfer part is 1/2 or more of the depth of the liquid pool part in which the said water is stored, The other end surface part side which opposes said one end surface part is any one of Claim 1 thru | or 3 The heat pipe according to item.   The heat pipe according to claim 3, wherein a reinforcing member having a higher thermal conductivity than that of the water is fitted to the outer surface of the convex portion outside the container.   The heat pipe according to claim 3, wherein one end surface portion on which the convex portion is formed has a tapered portion.   The heat pipe according to claim 6, wherein the taper-shaped portion inside the container is coated with a fluorine-based resin.   The heat pipe according to claim 6 or 7, wherein a heat-shrinkable tube is wound around an outer surface of the tapered portion.

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