JP2021055914A - heat pipe - Google Patents

Abstract

To provide a heat pipe having an excellent heat transport characteristic.SOLUTION: A heat pipe 1 comprises a tubular vessel 3 having an internal space S which is sealed with a working fluid F, and the tubular vessel 3 has an evaporation part 5 for making an air-phase F(g) working fluid change a phase by evaporating a liquid-phase working fluid F(L), and a condensing part 7 arranged apart from the evaporation part 5, condensing the air-phase working fluid F(g), and making the liquid-phase working fluid F(L) change a phase. The evaporation part 5 has a tubular wick structure 9 composed of a porous metal material, has an external peripheral face 11a which is located while opposing an internal peripheral face 3a of the tubular vessel 3 between the evaporation part 5 and the condensing part 7, and comprises an inner pipe member 11 composed of a non-porous metal material. A flow passage 13 in which the liquid-phase working fluid F(L) can flow along a longitudinal direction L of the tubular vessel 3 is formed in a boundary portion between the internal peripheral face 3a of the tubular vessel 3 and the external peripheral face 11a of the inner pipe member 11.SELECTED DRAWING: Figure 2

Description

The present invention relates to heat pipes having heat transport properties.

In recent years, electronic components such as semiconductor elements mounted on electric and electronic devices such as digital cameras and mobile phones, including notebook computers, tend to generate more heat due to high-density mounting due to higher functionality. Therefore, it is important to adopt a configuration that enables efficient cooling. As a means for cooling the electronic component, for example, a method of cooling using a heat pipe can be mentioned.

Here, the heat pipe includes a tubular container having an internal space in which a working fluid is sealed. The tubular container has an evaporating portion on one end side that evaporates the working fluid of the liquid phase to change the working fluid of the gas phase into a phase, and condenses the working fluid of the gas phase on the other end side of the liquid phase. It has a condensing part that changes the phase to the working fluid of. The working fluid whose phase is changed from the liquid phase to the gas phase in the evaporation part flows from the evaporation part to the condensing part. The working fluid whose phase is changed from the gas phase to the liquid phase in the condensing part flows from the condensing part to the evaporating part. In this way, the circulating flow of the working fluid is formed between the evaporating part and the condensing part in the tubular container, so that heat is transferred between the evaporating part and the condensing part in the tubular container.

As a conventional heat pipe, for example, a configuration in which a wick structure made of a sintered body of particulate metal powder (hereinafter, may be referred to as “wick structure (metal powder)”) is provided in the evaporation portion of the container. Can be mentioned. Since the wick structure (metal powder) constituting the evaporation part has excellent holding power of the working fluid of the liquid phase, the heat pipe is in a position where the evaporation part side is higher than the condensation part side, that is, the so-called top heat. Even if it is installed in the posture of, it is possible to prevent dryout (a phenomenon in which the working fluid is depleted).

Further, in Patent Document 1, the present inventor comprises a sintered body of metal fibers such that the intermediate portion between the evaporation portion and the condensing portion is connected to the wick structure (metal powder) of the evaporation portion. By forming a wick structure (hereinafter, sometimes referred to as "wick structure (metal fiber)") and further increasing the capillary force in the intermediate portion, the liquid phase from the condensing portion to the evaporating portion side. We proposed a heat pipe that promotes the reflux of the working fluid and improves the heat transport characteristics.

International Publication No. 2019/131790 (especially Fig. 6)

By the way, a part of the flow of the working fluid of the gas phase from the evaporating part to the condensing part is the flow of the working fluid of the liquid phase passing through the wick structure (metal fiber) near the end of the wick structure (metal fiber). When they collide with each other, so-called counterflow occurs, which may cause turbulence in the circulating flow of the working fluid. It is considered that the heat transport characteristics of the heat pipe will be further improved by suppressing the turbulence of the circulating flow of the working fluid.

An object of the present invention is to provide a heat pipe having excellent heat transport characteristics by suppressing turbulence of the circulating flow of the working fluid of the gas phase from the evaporation part to the condensing part.

The present inventors are premised on a configuration in which a tubular wick structure (metal powder) having excellent holding power of a working fluid in a liquid phase is provided in an evaporating part of a tubular container (container), and further heat transport characteristics are further provided. As a result of studies for improvement, by providing an inner tube member made of a non-porous structural material that does not allow the working fluid of the liquid phase to permeate so as to be connected (connected) to the wick structure (metal powder). We have found that the turbulence of the working fluid flow due to the counterflow as described above can be suppressed and a good circulating flow of the working fluid can be formed between the evaporating part and the condensing part in the tubular container. It came to be completed.

That is, the gist structure of the present invention is as follows.
(1) A tubular container having an internal space in which a working fluid is sealed is provided, and the tubular container is separated from an evaporating part that evaporates the working fluid of a liquid phase and changes the phase into a working fluid of a gas phase. In a heat pipe having a condensing portion that is arranged at a predetermined position and has a condensing portion that condenses the working fluid of the gas phase and changes the phase into the working fluid of the liquid phase, the evaporating portion is a tubular wick structure made of a porous metal material. The tubular container is provided with an inner tube member made of a non-porous metal material, having an outer peripheral surface facing the inner peripheral surface of the tubular container between the evaporating portion and the condensing portion. A flow path through which the working fluid of the liquid phase can flow is formed along the longitudinal direction of the tubular container at the boundary between the inner peripheral surface and the outer peripheral surface of the inner pipe member. heat pipe.
(2) The heat pipe according to (1) above, wherein the evaporation portion is located on one end side portion of the tubular container, and the condensing portion is located on the other end side portion of the tubular container.
(3) The heat pipe according to (1) above, wherein the evaporation portion is located in the central portion of the tubular container, and the condensing portion is located in both end portions of the tubular container.
(4) A plurality of grooves extending along the longitudinal direction of the tubular container are formed on the inner peripheral surface of the tubular container, and the flow paths formed at the boundary portion are the plurality of grooves and the inner pipe. The heat pipe according to (1), (2) or (3) above, which is partitioned from the outer peripheral surface of the member.
(5) The heat pipe according to any one of (1) to (4) above, wherein the wick structure is made of a sintered body of copper powder.
(6) The heat pipe according to any one of (1) to (5) above, wherein the inner pipe member is a copper pipe.

According to the present invention, a good circulating flow of the working fluid can be formed between the evaporating part and the condensing part in the tubular container, and the working fluid has excellent heat transport characteristics.

FIG. 1 is a diagram for explaining a flow of a working fluid generated inside a heat pipe (comparative example). 2 (a) to 2 (d) are views showing the internal structure of the heat pipe of the first embodiment according to the present invention, FIG. 2 (a) is a vertical sectional view, and FIG. 2 (b) is a view. 2 (a) bb cross-sectional view FIG. 2 (c) is a cc cross-sectional view of FIG. 2 (a), and FIG. 2 (d) is a dd cross-sectional view of FIG. 2 (a). FIG. 3 is a diagram for explaining the flow of the working fluid generated inside the heat pipe of FIG. FIG. 4 is a vertical cross-sectional view showing the internal structure of the heat pipe of the second embodiment. 5 (a) and 5 (b) are cross-sectional views showing two modified examples of the inner pipe member. FIG. 6 shows a modified example of the shape of a plurality of grooves formed on the inner peripheral surface of the tubular container, and is a cross section of the heat pipe bb when cut at the same position as in FIG. 2 (b). It is a figure.

Next, preferred embodiments of the present invention will be described below.

First, the flow of the working fluid generated inside the heat pipe (comparative example) will be described with reference to FIG. In FIGS. 1 and 3, the direction in which the working fluid F (L) of the liquid phase flows is indicated by a black arrow, and the direction in which the working fluid F (g) of the gas phase flows is indicated by a white arrow. ..

The heat pipe 100 has improved heat transport characteristics by increasing the capillary force in the intermediate portion located between the evaporation portion and the condensing portion. However, the wick structure (metal powder) 109 and the wick structure (metal fiber) 110 differ in the size and properties of the flow path through which the working fluid F (L) of the liquid phase passes, and the wick structure (metal powder) 109 The movement speed of the liquid phase working fluid F (L) tends to be slower than that of the wick structure (metal fiber) 110. Therefore, as shown in FIG. 1, the wick structure in which the working fluid F (L) of the liquid phase that has moved the wick structure (metal fiber) 110 due to the capillary force or the like is connected to the wick structure (metal powder) 109. Even if the end 110a of the body (metal fiber) 110 is reached, the wick structure (metal powder) 109 cannot immediately take in all of the working fluid F (L) of the liquid phase that has reached it. As a result, the working fluid F (L) of a part of the liquid phase accumulates at the end 110a of the wick structure (metal fiber) 110 connected to the wick structure (metal powder) 109.

Further, the vapor (gas phase working fluid F (g)) evaporated in the evaporation section 105 passes through the internal space S100 of the container 103 and heads for the condensation section. Here, as shown in FIG. 1, it is considered that a part of the working fluid F (g) of the gas phase invades the flow path (particularly near the end 110a) through which the working fluid F (L) of the liquid phase passes. In particular, as the amount of heat input to the evaporation section 105 increases, the momentum of the vapor generated from the evaporation section 105 increases, passes through the inner surface of the wick structure (metal fiber) 110, and the vapor passes through the liquid phase working fluid F ( It is considered that it invades the flow path through which L) passes.

Since the working fluid F (L) of a part of the liquid phase is accumulated near the end 110a, the working fluid F (L) of this liquid phase and the working fluid F (g) of the gas phase collide (counterflow CF). ) Is likely to occur. When the counterflow CF is generated, the inflow (supply) of the working fluid F (L) of the liquid phase into the evaporation section 105 is hindered, and the heat transport characteristics of the heat pipe 100 are deteriorated.

An object of the present invention is to provide a heat pipe having excellent heat transport characteristics by suppressing turbulence of the circulating flow of the working fluid of the gas phase from the evaporation part to the condensing part. The configuration of the heat pipe according to the present invention will be described below.

<First Embodiment>
2 (a) to 2 (d) are views showing the internal structure of the heat pipe of the first embodiment according to the present invention, FIG. 2 (a) is a vertical sectional view, and FIG. 2 (b) is a view. 2 (a) is a bb cross-sectional view, FIG. 2 (c) is a cc cross-sectional view of FIG. 2 (a), and FIG. 2 (d) is a dd cross-sectional view of FIG. 2 (a). In FIG. 2, the illustration of the working fluid sealed inside the heat pipe is omitted.

The heat pipe 1 shown in FIG. 2 includes a container 3 which is a tubular container having an internal space S in which a working fluid F is sealed.

The container 3 is arranged at a position separated from the evaporation unit 5 and the evaporation unit 5 that evaporates the working fluid F (L) of the liquid phase to change the phase to the working fluid F (g) of the gas phase, and is arranged in the gas phase. It has a condensing portion 7 that condenses the working fluid F (g) and changes the phase to the working fluid F (L) of the liquid phase. The container 3 shown in FIG. 2 has an evaporation portion 5 on one end side portion and a condensing portion 7 on the other end side portion, and is configured as a closed tube. The extending shape of the container 3 in the longitudinal direction is not particularly limited to the linear shape shown in FIG. 2A, the shape having a curved portion, and the like. The outer contour shape of the container when cut in the direction orthogonal to the longitudinal direction of the container 3 is not only the substantially circular shape shown in FIGS. 2 (b) to 2 (d), but also a flat shape, a polygonal shape such as a quadrangle, and the like. Not limited. The wall thickness of the container 3 is not particularly limited, but is, for example, 50 to 1000 μm. The outer diameter of the container 3 is not particularly limited, but for example, when the container 3 has a substantially circular outer surface contour shape, it is preferably in the range of 5 to 20 mm. Further, the container 3 may be a bare tube whose inner peripheral surface is formed of a smooth surface having no unevenness, but as will be described later, a plurality of containers extending along the longitudinal direction of the container 3 on the inner peripheral surface. A groove tube having a groove 15 formed therein is preferable in that it exerts a capillary force for transporting the working fluid of the liquid phase over the entire length of the container.

The material of the container 3 is not particularly limited. For the container 3, for example, copper, a copper alloy, or the like can be used because it has excellent thermal conductivity. From the viewpoint of weight reduction, for example, aluminum, an aluminum alloy, or the like can be used for the container 3. For the container 3, for example, stainless steel or the like can be used because of its high strength. In addition, for the container 3, for example, tin, tin alloy, titanium, titanium alloy, nickel, nickel alloy or the like may be used depending on the usage situation.

In FIG. 2, the evaporation unit 5 is formed on one end side of the container 3 and has a function of receiving (absorbing heat) heat from a thermally connected heating element (not shown). Specifically, the evaporation unit 5 absorbs the heat received from the heating element as latent heat of evaporation by evaporating the working fluid F (L) of the liquid phase and changing the phase to the working fluid F (g) of the gas phase. .. The evaporation unit 5 has a tubular wick structure 9 on the inner peripheral surface side of the container 3.

The wick structure 9 is made of a porous metal material and has a large number of pores through which the working fluid F (L) of the liquid phase can pass. The wick structure 9 is preferably made of a sintered body of copper powder. According to such a configuration, the wick structure 9 has high thermal conductivity, exhibits dryout resistance and the like, and has reverse operability. The reverse operability means a performance that exerts a function even when the position of the evaporation part 5 is higher than the position of the condensation part 7.

The metal type of the metal powder that is the raw material of the wick structure 9 is not particularly limited, and examples thereof include copper and copper alloys. The average primary particle size of the metal powder is not particularly limited, but is preferably in the range of 10 to 300 μm, for example.

In FIG. 2, the condensing portion 7 is formed on the other end side portion of the container 3, and the working fluid F (g) of the gas phase that has been transported by changing the phase in the evaporating portion 5 is exchanged with heat (FIG. 2). It has a function to dissipate heat by (not shown). Specifically, the condensing unit 7 condenses the working fluid F (g) in the gas phase and changes the phase to the working fluid F (L) in the liquid phase, so that the working fluid F (g) is transported as latent heat of condensation. Heat is released to the outside of the heat pipe 1.

Further, the heat pipe 1 of the present embodiment is provided with an inner pipe member 11 on the inner peripheral surface side of the container 3 between the evaporation portion 5 and the condensing portion 7 (intermediate portion).

The inner pipe member 11 has an outer peripheral surface 11a located opposite to the inner peripheral surface 3a of the container 3, and is made of a non-porous structural material through which the working fluid F (L) of the liquid phase cannot pass. The inner pipe member 11 is preferably made of a copper pipe. Further, a flow path for flowing the working fluid F (L) of the liquid phase along the longitudinal direction L of the container 3 at the boundary portion defined by the inner peripheral surface 3a of the container 3 and the outer peripheral surface 11a of the inner pipe member 11. 13 is formed.

The inner pipe member 11 is made of a non-porous structural material through which the working fluid F (L) of the liquid phase cannot pass. Therefore, the working fluid F (L) of the liquid phase cannot pass through the inner pipe member 11 in the radial direction, and is formed between the outer peripheral surface 11a of the inner pipe member 11 and the inner peripheral surface of the container 3. It moves through the flow path 13 to the end position of the wick structure 9 connected (connected) to the inner pipe member 11 by capillary force or the like.

Further, the connecting portion between the wick structure 9 and the inner pipe member 11 is connected (connected). Therefore, the working fluid F (L) of the liquid phase does not leak from the connecting portion to the internal space S, and can be reliably moved to the inside of the wick structure 9. As a result, the flow of the working fluid F (g) of the gas phase that has absorbed heat in the evaporation section 5 toward the condensing section 7 is not disturbed at the connecting section, and the evaporation section 5 and the condensing section 7 of the heat pipe 1 are not disturbed. A good circulating flow of the working fluid F can be formed between them.

Even if the inner pipe member 11 is thinner than the wick structure (metal fiber) 110 described in Patent Document 1 and FIG. 1, gas-liquid separation of the working fluid F can be reliably performed. The thickness of the inner tube member 11 is not particularly limited, but can be formed, for example, 0.1 to 1.0 mm. Further, since the inner pipe member can be easily mounted in the container 3 as compared with the wick structure (metal fiber) 110 described in Patent Document 1 and FIG. 1, productivity and yield can be increased.

It is preferable that a plurality of grooves 15 extending along the longitudinal direction L of the container 3 are formed on the inner peripheral surface 3a of the container 3. By forming the plurality of grooves 15, capillary force can be exerted when the working fluid F (L) of the liquid phase is transported inside the heat pipe 1. Therefore, even if the heat pipe 1 is installed in the top heat position, the working fluid F (L) of the liquid phase can be reliably transported from the condensing unit 7 to the evaporation unit 5.

Further, the flow path 13 formed at the boundary portion defined by the inner peripheral surface 3a of the container 3 and the outer peripheral surface 11a of the inner pipe member 11 is divided by a plurality of grooves 15 and the outer peripheral surface 11a of the inner pipe member 11. It is preferably formed. As a result, the capillary force in the intermediate portion located between the evaporation portion 5 and the condensing portion 7 is further increased, and the transport speed of the working fluid F (L) in the liquid phase can be increased.

In the heat pipe 1 of the present embodiment, the inner peripheral surface 3a of the container 3 is covered with the wick structure 9 at the portion where the evaporation portion 5 is formed, and is condensed with the portion where the evaporation portion 5 is formed. The space between (intermediate parts) where the portion 7 is formed is covered with the inner pipe member 11, and the inner peripheral surface of the container 3 remains exposed at the portion where the condensed portion 7 is formed. Existing.

<Second embodiment>
FIG. 4 is a vertical cross-sectional view showing the internal structure of the heat pipe 1A of the second embodiment. When the constituent members shown in FIG. 4 are the same as the constituent members shown in FIG. 2, they are designated by the same reference numerals.

The heat pipe 1A shown in FIG. 4 includes a container 3 which is a tubular container having an internal space S in which a working fluid F is sealed. In the container 3, the evaporation portion 5A is located in the central portion of the container 3, and the two condensing portions 7A and 7B are located at both ends of the container 3 and are formed between the evaporating portion 5A and the two condensing portions 7A and 7B. The middle part between the two places is configured as a heat insulating portion, and the container as a whole is configured as a closed pipe. The evaporation unit 5A has a tubular wick structure 9A on the inner peripheral surface side of the container 3.

Further, the heat pipe 1A of the present embodiment is located on the inner peripheral surface side of the container 3 at two intermediate portions (insulation portions) formed between the evaporation portion 5 and the condensation portions 7A and 7B, respectively. The inner pipe members 11A and 11B are provided.

Further, a flow path for flowing the working fluid F (L) of the liquid phase along the longitudinal direction L of the container 3 at the boundary portion defined by the inner peripheral surface 3a of the container 3 and the outer peripheral surface 11a of the inner pipe member 11. 13 is formed.

The inner pipe member 11 is made of a non-porous structural material through which the working fluid F (L) of the liquid phase cannot pass. Therefore, the working fluid F (L) of the liquid phase cannot pass through the inner pipe member 11 in the radial direction, and is between the outer peripheral surface 11a of the inner pipe member 11 and the inner peripheral surface 3a of the container 3. Through the formed flow path 13, it moves to the end position of the wick structure 9 connected (connected) to the inner tube member 11 by capillary force or the like.

Further, the connecting portion between the wick structure 9 and the inner pipe member 11 is connected (connected). Therefore, the working fluid F (L) of the liquid phase does not leak from the connecting portion to the internal space S, and can be reliably moved to the inside of the wick structure 9. As a result, the working fluid F (g) of the gas phase that has absorbed heat in the evaporation portion 5A located in the central portion of the container 3 is divided into both the condensing portions 7A and 7B located in both end portions of the container 3. The flow in two directions is not disturbed at the connecting portion, and two circulating flows that serve as different paths for the working fluid F are formed in good condition between the evaporation portion 5 and the condensing portions 7A and 7B of the heat pipe 1. can do.

<Other Embodiments>
As another embodiment, the inner pipe member 11 shows a case where a copper pipe is used in the first and second embodiments, but the configuration is not limited to this, and is, for example, as shown in FIG. 5 (a). The inner tube member 11A formed by rolling the copper foil into a C-shaped cross-sectional shape, and the inner tube member 11B formed into a circular cross-sectional shape in which both ends of the copper foil are overlapped as shown in FIG. 5 (b). It can be made into various aspects such as using. Further, although the cross-sectional shape of the groove 15 is substantially triangular in the first and second embodiments, the cross-sectional shape is not limited to such a configuration, and for example, in the other embodiments shown in FIG. In addition to the trapezoidal shape such as the groove 15A of the heater pipe 1B, various shapes such as a rectangular shape can be adopted.

<Heat transport mechanism of heat pipe>
Next, the mechanism of heat transport of the heat pipe 1 of the present invention will be described below using the heat pipe 1 of the first embodiment shown in FIGS. 2 and 3. First, when the evaporating part 5 of the heat pipe 1 receives heat from a thermally connected heating element (not shown), the evaporating part 5 evaporates the working fluid F (L) of the liquid phase to operate the gas phase. By changing the phase to the fluid F (g), the heat received from the heating element is absorbed as latent heat of evaporation. Next, the working fluid F (g) of the gas phase that has absorbed heat in the evaporation section 5 passes through the steam flow path that is the internal space S of the container 3, and the evaporation section (heat receiving section) 5 passes in the longitudinal direction L of the container 3. The heat received from the heating element is transported from the evaporation unit 5 to the condensing unit 7 by flowing from the evaporating unit (heat radiating unit) 7.

After that, the working fluid F (g) of the gas phase transported to the condensing unit 7 is phase-changed to the liquid phase by the heat exchange means (not shown) at the condensing unit 7. Further, the heat of the transported heating element is released to the outside of the heat pipe 1 as latent heat of condensation. Then, the working fluid F (L) of the liquid phase, which has changed to the liquid phase by releasing heat in the condensing portion 7, returns from the condensing portion 7 to the evaporating portion 5 along the inner peripheral surface of the container 3. , A circulating flow of working fluid can be formed between the evaporation unit 5 and the condensation unit 7. At this time, in the intermediate portion where the working fluid F (L) of the liquid phase is in the process of returning from the condensing portion 7 to the evaporating portion 5, the inner peripheral surface 3a of the container 3 and the outer peripheral surface 11a of the inner pipe member 11 are partitioned. A flow path 13 is formed at the boundary portion to be formed. By this flow path 13, the capillary force in the intermediate portion is further increased, and the transport speed of the working fluid F (L) in the liquid phase can be increased. Further, as compared with the case where the wick structure (metal fiber) is arranged in the intermediate portion as in the heat pipe described in Patent Document 1, the turbulence of the circulation flow of the working fluid F (L) can be suppressed, and as a result, the turbulence of the circulation flow can be suppressed. The heat transport characteristics can be significantly improved.

<Manufacturing method of heat pipe>
Hereinafter, a specific example of the method for manufacturing the heat pipe of the present invention will be described. First, a container base material is prepared. The shape of the container base material may be appropriately selected from pipe materials, plate materials, foil materials and the like according to the shape of the heat pipe. Dirt and the like adhering to the surface of the container base material may lead to a decrease in the heat transfer ability of the heat pipe, and therefore it is preferable to clean the heat pipe. The cleaning may be carried out by a general method, for example, solvent degreasing, electrolytic degreasing, etching, oxidation treatment and the like may be performed.

Next, a core rod having a predetermined shape (for example, a stainless steel core rod) is inserted and arranged at the inner center position of the container base material, and then formed between the inner surface of the container base material and the outer surface of the core rod. A metal powder (for example, copper powder), which is a raw material of the wick structure, is loaded into the gap.

Next, a step of sintering the metal powder (sintering step) and a step of loading the inner tube member into the container base material (loading step) are performed, but the order in which the steps are performed is in no particular order and is not particularly limited. do not.

For example, when the loading step is performed after the sintering step, first, the heat treatment is performed in a reducing atmosphere such as hydrogen gas or a hydrogen-containing gas of _{hydrogen gas and an inert gas (N 2, Ar, He, etc.).} A wick structure (metal powder) is produced by applying and sintering the metal powder. Next, the core rod in the container base material is pulled out and removed, and then the inner pipe member (for example, a copper pipe) is pushed into the container base material to a position where it abuts on the sintered body of the sintered metal powder and loaded.

When the sintering step is performed after the loading step, the inner tube member is first pushed into the container base material to a position where it abuts the metal powder loaded and loaded. At this time, the abutted end portion of the inner pipe member is strongly pushed into the metal powder so as to be embedded in the metal powder, for example, about 1 to 3 mm. It is preferable in that a strong bond with the pipe member can be obtained. _{After that, a wick structure (N 2} , Ar, He, etc.) is heat-treated in a reducing atmosphere such as hydrogen gas or a hydrogen-containing gas of hydrogen gas and an inert gas (N 2, Ar, He, etc.), and the metal powder is sintered to form a wick structure (N 2, Ar, He, etc.). Metal powder) is produced.

After loading the inner pipe member, only the other end of the container (tube material) is sealed, leaving the sealing port which is one end, and the working fluid is injected from the sealing port. After injecting the working fluid, the inside of the container is degassed by heating, vacuum degassing, etc. to reduce the pressure. After that, a heat pipe is manufactured by sealing the sealing port.

The sealing method is not particularly limited, and examples thereof include TIG welding, resistance welding, pressure welding, and soldering. The first sealing (sealing only the other end) is a step performed to seal the portion other than the portion where the gas inside escapes during the subsequent degassing, and the second sealing. Sealing (sealing of the sealing port) is a step performed to seal the portion where the gas inside escapes during degassing.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes all aspects included in the concept of the present invention and claims, and varies within the scope of the present invention. Can be modified to.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

(Example 1)
The heat pipe of the first embodiment is a cylindrical heat pipe 1 having an internal structure shown in FIG. The container 3 has, for example, a length of 400 mm and a diameter of 8 mm. On the inner peripheral surface 3a of the container 3, 60 grooves (groove width: 0.2 mm, groove depth: 0.2 mm) extending over the entire length of the container 3 and having a triangular cross section were formed. The wick structure (metal powder) 9 was heat-treated in a hydrogen gas atmosphere using copper powder having an average particle size of 0.1 mm as the metal powder. An annular copper sintered body having a length of 100 mm and a thickness of 1 mm is formed on one end side portion (evaporation portion 5) inside the container 3 so that a groove on the inner peripheral surface 3a of the container 3 is filled. did. Further, between the evaporation portion 5 and the condensing portion 7, a copper pipe (diameter 7 mm, length 100 mm, thickness) which is an inner pipe member 11 having an outer peripheral surface 11a facing the inner peripheral surface 3a of the container 3 is provided. 0.5 mm) was pushed into the container 3 until it hit one end of the wick structure (metal powder) 9 and loaded. At the boundary portion defined by the plurality of grooves 15 formed on the inner peripheral surface 3a of the container 3 and the outer peripheral surface 11a of the inner pipe member 11, the working fluid F of the liquid phase is formed along the longitudinal direction L of the container 3. (L) formed a flowable flow path 13. After loading the inner pipe member 11, only the other end of the container 3 is sealed, leaving the sealing port at one end, and water, which is the working fluid F (L), is injected from the sealing port, and then the container. The inside of No. 3 was degassed to reduce the pressure, and then the sealing port was sealed to prepare the heat pipe 1.

(Comparative Example 1)
The heat pipe 100 of Comparative Example 1 was produced so as to have the same configuration as the heat pipe of Example 1 except that the wick structure (metal fiber) 110 shown in FIG. 1 was arranged instead of the copper pipe. .. As the metal fiber, a copper fiber was used. The dimensions of the metal fibers were such that the fiber length was 1.4 mm and the fiber diameter was 30 μm, and the metal fibers were heat-treated together with the wick structure (metal powder) and sintered.

(Performance evaluation)
The performance of the heat pipe was evaluated under the following conditions.
1. 1. A heating element (heating amount 30W to 150W) was attached to the outer surface of the evaporation part (heat receiving part) which is one end side of the heat pipe.
2. A heat exchange means was attached to the condensing part (heat dissipation part), which is the other end of the heat pipe.
3. 3. A heat insulating material was attached to the intermediate part between the evaporation part and the condensing part to form a heat insulating part.
4. In the state of being installed in the horizontal direction, the amount of heat input at the evaporation part is increased by 10W from 30W, the magnitude of the amount of heat input just before the temperature of the evaporation part becomes unsteady is measured, and the measured amount of heat input is measured. The maximum heat transport amount was Qmax (W).

As a result, it was found that the heat pipe 1 of Example 1 had a maximum heat transport amount increased by 10% as compared with the heat pipe of Comparative Example 1, and the performance of the heat pipe was improved.

1,1A, 1B heat pipe 3,3A Tubular container (or container)
5, 5A Evaporation part 7, 7A, 7B Condensing part 9, 9A, 9B Wick structure 11, 11A, 11B Inner pipe member (or copper pipe)
13 Flow path 15, 15A Groove F Working fluid F (L) Liquid phase working fluid F (g) Gas phase working fluid L Longitudinal direction of tubular container S Internal space

Claims (6)

It has a tubular container with an internal space filled with working fluid.
The tubular container is
An evaporating part that evaporates the working fluid of the liquid phase and changes the phase to the working fluid of the gas phase,
In a heat pipe provided at a position separated from the evaporation portion and having a condensing portion that condenses the working fluid of the gas phase and changes the phase into the working fluid of the liquid phase.
The evaporation portion has a tubular wick structure made of a porous metal material and has a tubular wick structure.
An inner tube member having an outer peripheral surface facing the inner peripheral surface of the tubular container and made of a non-porous metal material is provided between the evaporation portion and the condensing portion.
At the boundary between the inner peripheral surface of the tubular container and the outer peripheral surface of the inner pipe member, a flow path through which the working fluid of the liquid phase can flow is formed along the longitudinal direction of the tubular container. The characteristic heat pipe. The heat pipe according to claim 1, wherein the evaporation portion is located on one end side portion of the tubular container, and the condensing portion is located on the other end side portion of the tubular container. The heat pipe according to claim 1, wherein the evaporation portion is located in a central portion of the tubular container, and the condensing portion is located in both end portions of the tubular container. A plurality of grooves extending along the longitudinal direction of the tubular container are formed on the inner peripheral surface of the tubular container.
The heat pipe according to claim 1, 2 or 3, wherein the flow path formed at the boundary portion is partitioned by the plurality of grooves and the outer peripheral surface of the inner pipe member. The heat pipe according to any one of claims 1 to 4, wherein the wick structure is made of a sintered body of copper powder. The heat pipe according to any one of claims 1 to 5, wherein the inner pipe member is a copper pipe.

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