Heat transport element and method for manufacturing heat transport element

Abstract

This heat transport element includes: a heat exchange part extending in a first direction; and a vapor chamber connected to a first end of the heat exchange part and having a contact surface in contact with a heating element. The vapor chamber includes: a first container communicating with an internal space of the heat exchange part to form a storage chamber in which a working fluid is stored; and a first wick disposed in the storage chamber and capable of holding the working fluid. The first container has a lower wall, an upper wall, and a column in contact with the lower wall and the upper wall. The heat exchange part has a second container forming the internal space, and at least a portion of the column is disposed at a location overlapping the second container when viewed in the first direction.

Description

Heat transport element and method for manufacturing the same

[0001] The present invention relates to a heat transport element and a method for manufacturing a heat transport element.This application claims priority to Japanese Patent Application No. 2024-064566, filed on April 12, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a cooler for cooling a heat-generating element such as an electronic component, which includes a heat receiving part on which the heat-generating element is mounted, a heat pipe joined to the heat receiving part and containing a working fluid, and heat dissipation fins on the surface of the heat pipe. In this cooler, heat from the heat-generating element is transferred to the heat pipe via the heat receiving part, and when the working fluid in the heat pipe is heated to a temperature above its saturation temperature, the working fluid vaporizes. The vaporized working fluid condenses by dissipating heat to the outside via the heat pipe and the heat dissipation fins.

[0003] Japanese Patent Application Publication No. 2004-44966

[0004] Incidentally, a storage chamber for storing a working fluid may be provided within the heat receiving section, which is connected to the internal space of the heat exchange section (e.g., a heat pipe). Furthermore, if the storage chamber is provided with a wick capable of capturing and retaining the working fluid by capillary force, it is desirable for the wick in the storage chamber to smoothly recover the working fluid that condenses within the heat exchange section. However, due to the surface tension of the working fluid, etc., the liquid working fluid flowing toward the heat receiving section on the inner circumferential surface of the heat exchange section may accumulate at the connection between the heat exchange section and the heat receiving section, making it impossible to smoothly recover the working fluid with the wick in the storage chamber.

[0005] The present invention has been made in consideration of these circumstances, and aims to provide a heat transport element and a method for manufacturing a heat transport element that can smoothly recover working fluid condensed in the heat exchange section using a wick in the storage chamber.

[0006] In order to solve the above problem, a heat transport element of aspect 1 of the present invention comprises a heat exchanger extending in a first direction, and a vapor chamber connected to a first end of the heat exchanger and having a contact surface that contacts a heating element, wherein the vapor chamber comprises a first container that is connected to the internal space of the heat exchanger and forms a storage chamber in which a working fluid is stored, and a first wick that is arranged in the storage chamber and is capable of holding the working fluid, wherein the first container has a lower wall, an upper wall, and pillars that contact the lower wall and the upper wall, and the heat exchanger has a second container that forms the internal space, and at least a portion of the pillars is arranged in a position that overlaps with the second container when viewed from the first direction.

[0007] A second aspect of the present invention is the heat transport element according to the first aspect, further comprising a pillar wick provided on an outer peripheral surface of the pillar.

[0008] Aspect 3 of the present invention is a heat transport element according to aspect 1 or 2, further comprising a second wick provided in the internal space and capable of holding the working fluid, the second wicks being spaced apart circumferentially around the central axis of the second container.

[0009] Aspect 4 of the present invention is a heat transport element according to any one of aspects 1 to 3, further comprising a second wick provided in the internal space and capable of holding the working fluid, the second wick comprising an extended wick protruding toward the first wick within the storage chamber.

[0010] Aspect 5 of the present invention is a heat transport element according to aspect 3 or 4, wherein, when viewed from the first direction, a plurality of the pillars and a plurality of the second wicks are arranged alternately in the circumferential direction around the central axis of the second container.

[0011] A sixth aspect of the present invention is the heat transport element according to any one of the first to fifth aspects, further comprising a heat dissipation fin joined to the outer peripheral surface of the heat exchange portion.

[0012] A seventh aspect of the present invention is a method for manufacturing a heat transport element, comprising: a vapor chamber preparation step of preparing a first container having an upper wall with a through hole formed therein, a lower wall, and a pillar that contacts the lower wall and the upper wall and is positioned so as to overlap at least partially with the through hole; a heat exchanger preparation step of preparing a heat exchanger having a second container with an open first end; and a connection step of inserting the first end of the heat exchanger into the through hole, wherein in the connection step, the second container is abutted against the pillar.

[0013] According to the above aspect of the present invention, the working fluid condensed in the heat exchange section can be smoothly collected by the wick in the storage chamber.

[0014] FIG. 1 is a cross-sectional view of a heat transport element according to a first embodiment. FIG. 2 is a cross-sectional view taken along the arrows II-II of the heat transport element shown in FIG. 1. FIG. 3 is a diagram illustrating the flow of working fluid at a junction between a first container and a second container of the heat transport element shown in FIG. 1. FIG. 4 is a diagram illustrating the flow of working fluid at a junction between a first container and a second container of a conventional heat transport element. FIG. 5 is a diagram illustrating the flow of working fluid at a junction between a first container and a second container of a conventional heat transport element. FIG. 6 is a partial cross-sectional view of a heat transport element according to a second embodiment. FIG. 7 is a cross-sectional view taken along the arrows V-V of the heat transport element shown in FIG. 4. FIG. 8 is a partial cross-sectional view of a heat transport element according to a third embodiment. FIG. 9 is a cross-sectional view taken along the arrows VII-VII of the heat transport element shown in FIG. 6. FIG. 10 is a cross-sectional view of heat transport elements according to other modified examples of the first to third embodiments.

[0015] Hereinafter, a heat transport element according to this embodiment will be described with reference to the drawings. (First Embodiment) As shown in Fig. 1, the heat transport element 1 includes a vapor chamber 2, a plurality of heat exchange units 3, and a plurality of heat dissipation fins 4. The number of heat exchange units 3 may be one. Furthermore, the heat transport element 1 does not need to include the heat dissipation fins 4. The heat exchange unit 3 in this embodiment is a heat pipe. However, a component other than a heat pipe (for example, a flat vapor chamber) may also be used as the heat exchange unit 3.

[0016] (Directional Definition) In this specification, the direction in which the heat exchange unit 3 extends is referred to as the first direction D1. In the first direction D1, the direction from the vapor chamber 2 toward the heat exchange unit 3 is referred to as the +D1 direction, and the direction from the heat exchange unit 3 toward the vapor chamber 2 is referred to as the -D1 direction. A direction perpendicular to the first direction D1 is referred to as the second direction D2. A direction perpendicular to both the first direction D1 and the second direction D2 is referred to as the third direction D3. Furthermore, in each heat exchange unit 3, the direction around the central axis of the heat exchange unit 3 is referred to as the circumferential direction.

[0017] The vapor chamber 2 includes a first container 21 and a first wick 22. The first container 21 is made of, for example, copper, a copper alloy, aluminum, an aluminum alloy, etc. The first container 21 may also be made of a material other than those listed above.

[0018] The first container 21 has a hollow box shape. The first container 21 is formed in a flat shape, with the outer dimensions in the second direction D2 and the third direction D3 being larger than the thickness dimension in the first direction D1. The first container 21 integrally includes a bottom wall 23, an outer peripheral wall portion 24, and an top wall 25. The bottom wall 23 is disposed in the −D1 direction (downward in FIG. 1 ) relative to the top wall 25. When viewed from the first direction D1, the bottom wall 23 has, for example, a rectangular shape. The bottom wall 23 extends along a plane including the second direction D2 and the third direction D3. The bottom wall 23 has a contact surface 23f facing the −D1 direction. The contact surface 23f is in direct or indirect contact with the heating element 100. Heat generating elements 100 such as various semiconductor elements including a CPU and a GPU are in thermal contact with the contact surface 23f via, for example, thermally conductive grease 101 containing a material with high thermal conductivity.

[0019] The outer peripheral wall portion 24 rises in the +D1 direction from the outer periphery of the lower wall 23. The upper wall 25 is disposed on the +D1 direction side of the lower wall 23, and the upper wall 25 and the lower wall 23 are spaced apart. The upper wall 25 has, for example, a rectangular shape when viewed from the first direction D1. The upper wall 25 extends along a plane including the second direction D2 and the third direction D3. The upper wall 25 is provided so as to cover the space inside the outer peripheral wall portion 24 from the +D1 direction side.

[0020] A plurality of pillars 27 are provided between the lower wall 23 and the upper wall 25. Each of the pillars 27 has a cylindrical shape extending along the first direction D1. The pillars 27 extending in the first direction D1 are connected to the lower wall 23 and the upper wall 25. More specifically, the pillars 27 are connected to the inner surface of the lower wall 23 facing the +D1 direction and the inner surface of the upper wall 25 facing the −D1 direction. The plurality of pillars 27 are arranged at intervals in the second direction D2 and the third direction D3. The pillars 27 may be joined to the lower wall 23 and the upper wall 25 by brazing, welding, adhesive bonding, or the like. The shape of the pillars 27 is not limited to a cylindrical shape, and may be an ellipse or a polygon when viewed from the first direction D1.

[0021] A storage chamber 28 is formed within the first container 21 and is surrounded by a lower wall 23, an outer peripheral wall portion 24, and an upper wall 25. The storage chamber 28 extends along a second direction D2 and a third direction D3. The dimension of the pillar 27 in the first direction D1 is equal to the dimension of the storage chamber 28 in the first direction D1. The storage chamber 28 stores a working fluid.

[0022] The working fluid is a heat transport medium made of a known phase change material, and changes between a liquid phase and a gas phase within the heat transport element 1. For example, water (pure water), alcohol, ammonia, etc. can be used as the working fluid. The working fluid may be described as a "liquid" when in the liquid phase and as a "vapor" when in the gas phase. When no particular distinction is made between the liquid phase and the gas phase, the working fluid may be described as a working fluid. The working fluid is not shown.

[0023] The first wick 22 is provided in the storage chamber 28. The first wick 22 is disposed within the storage chamber 28 along the lower wall 23. The first wick 22 has a predetermined thickness in the first direction D1. The first wick 22 is disposed away from the upper wall 25 in the −D1 direction. The first wick 22 may be formed of a powder wick made of a porous material sintered with metal powder such as copper, a wire wick made of a braided material made of multiple metal wires such as copper, or the like. The first wick 22 can capture and retain the working fluid within the first container 21 by its capillary force. In the first direction D1, the first wick 22 may have a recess recessed in the −D1 direction at a position overlapping with the heating element 100. Furthermore, a portion of the working fluid retained in the first wick 22 may be exposed within the recess.

[0024] The heat exchange units 3 are arranged at intervals in the second direction D2 and the third direction D3. In this embodiment, two heat exchange units 3 are arranged side by side at an interval in the second direction D2. Two heat exchange units 3 are arranged side by side at an interval in the third direction D3. Thus, in this embodiment, a total of four second containers 31 are provided. The number of second containers 31 may be one, two, three, or five or more. A first end 31s of each heat exchange unit 3 on the -D1 direction side is joined to the vapor chamber 2. The heat exchange unit 3 extends from the upper wall 25 of the vapor chamber 2, protruding in the +D1 direction.

[0025] The heat exchange unit 3 includes a cylindrical second container 31 and a second wick 32. The second container 31 is made of, for example, copper, a copper alloy, aluminum, an aluminum alloy, or the like. The second container 31 may be made of a material other than those listed above. The second container 31 is hollow and cylindrical and extends in the first direction D1. A first end 31s on the −D1 direction side is an open end, and a second end 31t on the +D1 direction side is a closed end.

[0026] An internal space 38 extending in the first direction D1 is formed within the second container 31. A first end 31s of the second container 31 is inserted into a through-hole 25h formed in the upper wall 25 of the vapor chamber 2 and joined to the upper wall 25 by brazing, welding, adhesive, or the like. As a result, the internal space 38 within the second container 31 communicates with the storage chamber 28 within the vapor chamber 2.

[0027] The second wick 32 is provided in the second container 31. The second wick 32 is disposed within the second container 31 along the inner circumferential surface 31f of the second container 31. In this embodiment, the second wick 32 is provided on the inner circumferential surface 31f of the second container 31 over the entire circumferential direction around the central axis C of the second container 31 (see FIG. 2). Furthermore, the second wick 32 extends in the first direction D1 along the inner circumferential surface 31f of the second container 31.

[0028] The second wick 32 is formed from a powder wick made of a porous body obtained by sintering metal powder such as copper, a wire wick made of a braided body made of multiple metal wires such as copper, or the like. The second wick 32 can capture and retain the working fluid condensed in the second container 31 by its capillary force. Note that the second wick 32 in the second container 31 does not have to be provided around the entire inner circumferential surface 31f. The second wick 32 may be provided at intervals in the circumferential direction. Furthermore, the second wick 32 is not an essential component, and the second wick 32 may be omitted.

[0029] Fig. 2 is a cross-sectional view taken along the line II-II of the heat transport element 1 shown in Fig. 1, and for the sake of explanation, the positions of the second container 31 and the second wick 32 of the heat exchange unit 3 are indicated by dashed lines. As shown in Fig. 2, two pillars 27 are provided on the -D1 direction side of one heat exchange unit 3. At least a portion of each pillar 27 is disposed in a position overlapping with the second container 31 when viewed from the first direction D1.

[0030] As shown in FIG. 1 , the heat dissipation fins 4 are joined to the outer peripheral surface of the heat exchanger 3. The heat dissipation fins 4 are formed in the shape of plates extending along the second direction D2 and the third direction D3. A plurality of the heat dissipation fins 4 are provided at intervals in the first direction D1. A cylindrical sleeve 41 extending in the first direction D1 is provided on the outer peripheral surface of the heat exchanger 3. Each heat dissipation fin 4 is joined to the second container 31 of the heat exchanger 3 via the sleeve 41. The heat dissipation fins 4 and the sleeve 41 are made of, for example, copper, a copper alloy, aluminum, an aluminum alloy, or the like. The heat dissipation fins 4 and the sleeve 41 may be made of a material other than those mentioned above.

[0031] <Function of Heat Transport Element 1> Next, the function of the heat transport element 1 will be described. The heat transport element 1 is used with the contact surface 23f in contact with the heating element 100. The heat transport element 1 is preferably oriented such that, for example, the first direction D1 coincides with the vertical direction. However, the heat transport element 1 may also be oriented such that the first direction D1 is inclined relative to the vertical direction. The heat transport element 1 may also be oriented such that the first direction D1 coincides with the horizontal direction.

[0032] In the heat transport element 1, heat generated by the heating element 100 is transferred to the liquid working fluid in the storage chamber 28 via the vapor chamber 2. When the working fluid is heated above its saturation temperature and vaporizes, the vapor flows from the storage chamber 28 into the internal space 38 of the heat exchange unit 3 (see arrow F1 in FIG. 1 ). The heat of the working fluid that has flowed into the internal space 38 is transferred to the heat dissipation fins 4 via the heat exchange unit 3. The heat of the working fluid transferred to the heat dissipation fins 4 is dissipated into the atmosphere surrounding the heat dissipation fins 4. As a result, the temperature of the working fluid in the internal space 38 drops, and the working fluid condenses. The liquid working fluid is captured by the second wick 32 provided in the second container 31 of the heat exchange unit 3 and returns to the first wick 22 in the storage chamber 28 of the vapor chamber 2 through the second wick 32.

[0033] The liquid that has returned to the first wick 22 again receives heat from the heating element 100 and evaporates. In this way, the heat transport element 1 can repeatedly transport the heat of the heating element 100 to the heat dissipation fins 4. Therefore, the heating element 100 can be cooled.

[0034] Here, the state in which the liquid working fluid passes through the second wick 32 and returns to the first wick 22 in the storage chamber 28 of the vapor chamber 2 will be described using FIGS. 3A to 3C. FIGS. 3A to 3C illustrate only the first end 31s of the heat exchange unit 3 and a portion of the upper wall 25 of the first container 21, and omit the second wick 32 and the pillars 27. FIG. 3A illustrates a case in which the end face 31e of the first end 31s and the lower face 25b of the upper wall 25 are at the same position in the first direction D1, i.e., there is no step between the end face 31e and the lower face 25b. In this case, the liquid working fluid moves smoothly from the end face 31e along the lower face 25b and further along the inner wall surface or the pillars 27 of the first container 21 to the first wick 22. Note that at the first end 31s or the lower face 25b, some of the liquid forms droplets and falls into the first wick 22.

[0035] On the other hand, when the end surface 31e is located closer to the +D1 direction than the bottom surface 25b, as shown in FIG. 3B, a depression is formed at the connection between the heat exchanger 3 and the first container 21. In this case, due to the surface tension of the liquid, the liquid flowing toward the vapor chamber 2 at the first end 31s of the heat exchanger 3 may accumulate in the depression, preventing the liquid from smoothly returning to the first wick. Furthermore, the liquid accumulated at the first end 31s of the heat exchanger 3 narrows the vapor inlet to the internal space 38, making it difficult for the vapor to move toward the second end 31t of the heat exchanger 3. This obstruction of the flow of the working fluid may reduce the amount of heat dissipated by condensation of the working fluid, potentially reducing the cooling efficiency of the heating element 100. Similarly, when the end surface 31e is located closer to the -D1 direction than the bottom surface 25b, as shown in FIG. 3C, a step formed between the end surface 31e and the upper wall 25 may obstruct the flow of the liquid and vapor.

[0036] In this embodiment, the pillars 27 are provided so that the end face 31e of the first end 31s and the lower surface 25b of the upper wall 25 are positioned at the same position in the first direction D1. This allows both liquid and vapor working fluids to circulate smoothly within the heat transport element 1. Furthermore, because the end face 31e of the heat exchange unit 3 is connected to the lower wall 23 and the first wick 22 by the pillars 27, the outer peripheral surface 27a of the pillars 27 also serves as a liquid flow path. This allows a portion of the liquid that has moved to the first end 31s of the heat exchange unit 3 to be returned to the first wick 22 over a short distance.

[0037] <Method for Manufacturing Heat Transport Element 1> Next, a method for manufacturing the heat transport element 1 of this embodiment will be described. First, a vapor chamber 2 is prepared (vapor chamber preparation step). For example, a first container 21 is prepared, with pillars 27 and a first wick 22 provided therein. One or more through holes 25h are provided in the upper wall 25 depending on the number of heat exchange units 3 connected to the vapor chamber 2. The diameter of the through holes 25h is equal to or greater than the outer diameter of the heat exchange units 3. The pillars 27 are positioned so that at least a portion of the pillars 27 overlaps with the through holes 25h when viewed from the first direction D1. A heat exchange unit 3 is prepared (heat exchange unit preparation step). A metal cylinder that will become the second container 31 is prepared, and a second wick 32 is provided on the inner surface of the cylinder. The first end 31s of the cylinder is left open, and the second end 31t is closed.

[0038] Next, the first end 31s of the heat exchanger 3 is inserted into the through-hole 25h (connection process). At this time, the heat exchanger 3 is inserted until the end face 31e of the heat exchanger 3 contacts the upper end of the column 27. Thereafter, the first end 31s of the heat exchanger 3 is joined to the upper wall 25 by brazing, welding, adhesive, or the like. Note that when assembling the heat transport element 1, a working fluid is sealed in the storage chamber 28 and the internal space 38. Through these processes, it is possible to manufacture a heat transport element 1 in which the end face 31e of the first end 31s and the lower surface 25b of the upper wall 25 are positioned at the same position in the first direction D1.

[0039] The above-described manufacturing method is an example, and all preparation steps for the vapor chamber 2 and the heat exchanger 3 do not necessarily have to be completed before the connection step. For example, the second end 31t of the heat exchanger 3 may be closed after the connection step. Furthermore, the manufacturing method may include a step of providing the heat dissipation fins 4 on the heat exchanger 3.

[0040] As described above, the heat transport element 1 of this embodiment comprises a heat exchange section 3 extending in a first direction D1, and a vapor chamber 2 connected to a first end 31s of the heat exchange section 3 and having a contact surface 23f that contacts the heating element 100. The vapor chamber 2 comprises a first container 21 that is connected to the internal space 38 of the heat exchange section 3 and forms a storage chamber 28 in which a working fluid is stored, and a first wick 22 that is arranged in the storage chamber 28 and can hold the working fluid. The first container 21 has a lower wall 23, an upper wall 25, and pillars 27 that contact the lower wall 23 and the upper wall 25. The heat exchange section 3 has a second container 31 that forms the internal space 38, and at least a portion of the pillars 27 is arranged in a position that overlaps with the second container 31 when viewed from the first direction D1.

[0041] By providing the pillars 27 in this configuration, the end face 31e of the first end 31s and the lower surface 25b of the upper wall 25 are positioned at the same position in the first direction D1. In this case, the working fluid condensed in the heat exchange unit 3 smoothly moves along the end face 31e of the heat exchange unit 3 and the inner circumferential surface of the vapor chamber 2 to the first wick 22 in the storage chamber 28. If there is a step between the end face 31e of the first end 31s and the lower surface 25b of the upper wall 25, the liquid may remain near the first end 31s of the second container 31, making it difficult for the liquid to return to the first wick 22 and for vapor to move to the internal space 38 of the heat exchange unit 3. In contrast, in this embodiment, both the liquid and vapor working fluids can be smoothly circulated within the heat transport element 1. Furthermore, the end surface 31e of the heat exchange unit 3 and the lower surface 25b of the first container 21 are connected to the first wick 22 by the pillars 27, so that the outer peripheral surfaces 27a of the pillars 27 serve as a flow path for the liquid. This allows a portion of the liquid that has moved to the first end 31s of the heat exchange unit 3 to return to the first wick 22 in a short distance.

[0042] The heat transport element 1 further includes heat dissipation fins 4 joined to the outer peripheral surface of the heat exchanger 3. With this configuration, the heat of the vaporized working fluid can be efficiently dissipated into the surrounding atmosphere via the heat dissipation fins 4.

[0043] The manufacturing method of the heat transport element 1 of this embodiment includes a vapor chamber preparation step of preparing a first container 21 having an upper wall 25 with a through hole 25h formed therein, a lower wall 23, and a pillar 27 that is in contact with the lower wall 23 and the upper wall 25 and is positioned so as to at least partially overlap the through hole 25h, a heat exchanger preparation step of preparing a heat exchanger unit 3 having a second container 31 with an open first end 31s, and a connection step of inserting the first end 31s of the heat exchanger unit 3 into the through hole 25h, wherein the second container 31 is abutted against the pillar 27. In this way, by inserting the heat exchanger unit 3 into the vapor chamber 2 in which the pillar 27 is positioned so as to at least partially overlap the through hole 25h, it is possible to manufacture a heat transport element 1 in which the end face 31e of the first end 31s and the lower surface 25b of the upper wall 25 are positioned at the same position in the first direction D1.

[0044] Second Embodiment Next, a second embodiment of the heat transport element according to the present invention will be described, which has the same basic configuration as the first embodiment. Therefore, the same components are denoted by the same reference numerals, and their description will be omitted, and only the differences will be described.

[0045] FIG. 4 is a cross-sectional view showing the connection between the first container 21 and the second container 31 of the heat transport element 1 according to the second embodiment. The configuration other than that shown in FIG. 4 is the same as that of the first embodiment and is therefore not shown. As shown in FIGS. 4 and 5 , a columnar wick 22a is provided around the entire outer circumferential surface 27a of the column 27. The end of the columnar wick 22a on the +D1 direction side is in contact with the end surface 31e of the heat exchange unit 3 and the lower surface 25b of the upper wall 25 of the first container 21. The columnar wick 22a has a cylindrical shape that covers the column 27 when viewed from the first direction D1. When viewed from the first direction D1, a portion of the columnar wick 22a may be positioned so as to overlap with the internal space 38 of the heat exchange unit 3. In this embodiment, the first wick 22 and the columnar wick 22a are powder wicks made of a porous material obtained by sintering metal powder such as copper, and the first wick 22 and the columnar wick 22a are integrally formed.

[0046] The column wick 22a is not limited to the above example, and may be provided on a portion of the column 27 in the circumferential direction. For example, the column wick 22a may be provided only on the surface of the column 27 facing the central axis C in the circumferential direction. Furthermore, the column wick 22a and the first wick 22 may be separate bodies or may be made of different materials.

[0047] In this embodiment, the heat exchanger 3 does not include a second wick. In this case, in order to move the liquid in the heat exchanger 3 by gravity, it is preferable that the orientation of the heat transport element 1 is such that the first direction D1 coincides with the vertical direction. Note that in this embodiment, the heat exchanger 3 may include a second wick.

[0048] <Operation of the Heat Transport Element 1 of the Second Embodiment> The operation of the heat transport element 1 of the second embodiment will be described, focusing only on the differences from the first embodiment. Liquid condensed in the heat exchange unit 3 moves by gravity along the inner circumferential surface 31f toward the first end 31s. At the first end 31s, the liquid (1) is absorbed into the columnar wick 22a, (2) moves along the end surface 31e, the lower surface 25b of the first container 21, and other inner circumferential surfaces, or (3) forms droplets at the first end 31s and the lower surface 25b and falls downward, returning to the first wick 22.

[0049] As described above, the heat transport element 1 of this embodiment further includes the pillar wick 22 a provided on the outer circumferential surface 27 a of the pillar 27 .

[0050] With this configuration, the columnar wick 22a can capture, by capillary force, the liquid that has migrated along the inner circumferential surface 31f of the heat exchanger 3 to the first end 31s. Furthermore, the columnar wick 22a can serve as a flow path for the liquid, allowing the liquid to be returned to the first wick 22 more efficiently. Furthermore, the area where the heat exchanger 3 contacts the columns 27 and the columnar wick 22a can be secured. This allows the end face 31e of the first end 31s to be more reliably positioned in the first direction D1 when inserting the heat exchanger 3 into the vapor chamber 2.

[0051] (Third Embodiment) Next, a third embodiment of the heat transport element according to the present invention will be described, which has the same basic configuration as the first embodiment. Therefore, the same components are denoted by the same reference numerals, and their description will be omitted, and only the differences will be described.

[0052] Fig. 6 is a cross-sectional view showing the connection between the first container 21 and the second container 31 of the heat transport element 1 according to the third embodiment. The configuration other than that shown in Fig. 6 is the same as that of the first embodiment, and therefore is not shown in the drawings. As shown in Figs. 6 and 7, in this embodiment, when viewed from the first direction D1, each second wick 32 has an arc shape that covers a portion of the inner circumferential surface 31f. Furthermore, the multiple second wicks 32 are provided at intervals in the circumferential direction.

[0053] The second wick 32 has an extended wick 32a extending toward the first wick 22 within the storage chamber 28. A tip 32a1 of the extended wick 32a on the -D1 direction side is in contact with the first wick 22. The extended wick 32a may be inserted (embedded) within the first wick 22. The tip 32a1 of the extended wick 32a may also penetrate the first wick 22 and be in contact with the lower wall 23. The tip 32a1 of the extended wick 32a may also be spaced apart from the first wick 22 as long as it can quickly capture the working fluid that expands toward the first wick 22 due to the surface tension of the liquid.

[0054] When viewed from the first direction D1, the shape of the extended wick 32a is an arc shape similar to that of the second wick 32. In this embodiment, the second wick 32 including the extended wick 32a is a wire wick that is a braided body made of multiple metal wires such as copper, and is integrally formed from a wire wick having multiple wires extending in the first direction D1.

[0055] In this embodiment, two second wicks 32 are provided in one second container 31, and this pair of second wicks 32 are provided so as to face each other about the central axis C within the second container 31. The positions of the two pillars 27 and the pair of second wicks 32 in the circumferential direction are the same. In this case, the pillars 27 and the second wicks 32 may be in contact with each other. Each second wick 32 is provided in a range of, for example, 1 / 6 to 1 / 3 of the circumferential direction of the heat exchange unit 3. In this embodiment, the second wicks 32 are formed in a range of, for example, about 1 / 6 of the circumferential direction of the heat exchange unit 3.

[0056] <Operation of the Heat Transport Element 1 of the Third Embodiment> The operation of the heat transport element 1 of the third embodiment will be described, focusing only on the differences from the first and second embodiments. Liquid condensed in the heat exchange unit 3 moves along the second wick 32 or the inner circumferential surface 31f toward the first end 31s. At the first end 31s, the liquid (1) moves within the extension wick 32a, (2) moves along the end surface 31e, the lower surface 25b of the first container 21, and other inner circumferential surfaces, or (3) forms droplets at the first end 31s and the lower surface 25b and falls downward, returning to the first wick 22.

[0057] As described above, the heat transport element 1 of this embodiment further includes a second wick 32 that is provided in the internal space 38 and is capable of holding a working fluid, and the second wicks 32 are provided at intervals in the circumferential direction around the central axis C of the second container 31.

[0058] This configuration ensures a larger space for vapor movement in the internal space 38 while providing the second wick 32. Furthermore, the working fluid condensed in the heat exchanger 3 can be smoothly moved to the first end 31 s along the second wick 32 and the inner circumferential surface 31 f extending along the first direction D1.

[0059] The second wick 32 also includes an extended wick 32a that protrudes toward the first wick 22 within the storage chamber 28. This allows the extended wick 32a to function as a flow path that returns the liquid that has moved to the first end 31s to the first wick 22, thereby allowing the working fluid to circulate more efficiently within the heat transport element 1.

[0060] The technical scope of the present invention is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0061] For example, in the third embodiment, the circumferential positions of the pillars 27 and the second wick 32 are aligned, but the circumferential positions of the pillars 27 and the second wick 32 may be different. As shown in FIG. 8 , the pillars 27 and the second wicks 32 (extending wicks 32a) may be alternately arranged in the circumferential direction. This configuration ensures a larger space for vapor movement in the internal space 38 while still providing the second wick 32. Furthermore, the working fluid condensed in the heat exchange unit 3 can be smoothly moved along the second wick 32 and the inner circumferential surface 31f extending along the first direction D1 to the first end 31s.

[0062] Furthermore, the number of pillars 27 provided for one heat exchange unit 3 is not limited to two, and may be one, or may be three or more. The number of pillars 27 and the diameter of each pillar 27 are preferably set to a degree that does not impede both the flow of vapor from the storage chamber 28 to the internal space 38 and the flow of liquid from the first end 31s to the vapor chamber 2. Similarly, the diameter of the pillar wick 22a in the second embodiment is preferably set to a degree that does not impede the movement of the working fluid.

[0063] In the third embodiment, two second wicks 32 are provided in one heat exchanger 3, but the number of second wicks 32 in one heat exchanger 3 may be one or three or more. Furthermore, when the second wick 32 has an extended wick 32a, it is preferable that the number and circumferential dimension of the extended wicks 32a be set to an extent that does not impede the movement of the working fluid.

[0064] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, without departing from the spirit of the present invention.

[0065] DESCRIPTION OF SYMBOLS 1...Heat transport element 2...Vapor chamber 3...Heat exchange section (heat pipe) 4...Heat dissipation fin 21...First container 22...First wick 22a...Column wick 23f...Contact surface 27...Column 28...Storage chamber 31...Second container 31f...Inner peripheral surface 31s...First end 32...Second wick 32a...Extended wick 38...Internal space 100...Heat generating element

Claims

1. A heat transport element comprising: a heat exchange unit extending in a first direction; and a vapor chamber connected to a first end of the heat exchange unit and having a contact surface in contact with a heating element, wherein the vapor chamber comprises: a first container communicating with the internal space of the heat exchange unit and forming a storage chamber in which a working fluid is stored; and a first wick arranged in the storage chamber and capable of holding the working fluid, wherein the first container has a lower wall, an upper wall, and pillars in contact with the lower wall and the upper wall, and the heat exchange unit has a second container forming the internal space, and at least a portion of the pillars is arranged in a position overlapping with the second container when viewed from the first direction.

2. The heat transport element according to claim 1, further comprising a pillar wick provided on the outer peripheral surface of the pillar.

3. A heat transport element as described in claim 1 or 2, further comprising a second wick provided in the internal space and capable of holding the working fluid, the second wicks being provided at intervals in the circumferential direction around the central axis of the second container.

4. A heat transport element as described in any one of claims 1 to 3, further comprising a second wick provided in the internal space and capable of holding the working fluid, the second wick comprising an extension wick protruding toward the first wick within the storage chamber.

5. A heat transport element as described in claim 3 or 4, wherein, when viewed from the first direction, a plurality of the pillars and a plurality of the second wicks are arranged alternately in the circumferential direction around the central axis of the second container.

6. The heat transport element according to any one of claims 1 to 5, further comprising heat dissipation fins joined to the outer peripheral surface of the heat exchanger.

7. A method for manufacturing a heat transport element, comprising: a vapor chamber preparation step of preparing a first container having an upper wall with a through hole formed therein, a lower wall, and a pillar that contacts the lower wall and the upper wall and is positioned so as to overlap at least a portion of the through hole; a heat exchanger preparation step of preparing a heat exchanger having a second container with an open first end; and a connection step of inserting the first end of the heat exchanger into the through hole, wherein in the connection step, the second container is abutted against the pillar.

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