CN215647910U - Heat pipe - Google Patents
Heat pipe Download PDFInfo
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- CN215647910U CN215647910U CN202121092944.8U CN202121092944U CN215647910U CN 215647910 U CN215647910 U CN 215647910U CN 202121092944 U CN202121092944 U CN 202121092944U CN 215647910 U CN215647910 U CN 215647910U
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- wick structure
- heat pipe
- container
- wick
- wall portion
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Abstract
The present invention provides a heat pipe having a tubular container in which a working medium and a porous wick structure for transporting the working medium are accommodated in an internal space. The container has a bottom wall portion and an upper wall portion that are vertically opposed to each other in a cross section perpendicular to an extending direction that is a direction in which the container extends, and a pair of side wall portions. The side wall portions are connected to both side end portions of the bottom wall portion and both side end portions of the upper wall portion, respectively. The wick structure has a lower wick structure and a convex wick structure. The lower wick structure is formed in contact with the bottom wall portion, and the upper surface thereof is disposed facing the internal space. The convex wick structure protrudes upward from the upper surface of the lower wick structure, and has a width in a direction orthogonal to the vertical direction and the extending direction that is narrower than the width of the lower wick structure, and supports the upper wall portion.
Description
Technical Field
The present invention relates to a heat pipe as a heat conductive member.
Background
A conventional heat pipe includes a working medium such as water, a wick structure, and a container. The container is formed in a tubular shape, and houses the working medium and the wick structure. The wick structure is formed to face the upper and lower portions of the inner peripheral surface of the container in the vertical direction.
The container is disposed in contact with the heating element. The working medium is heated by the heating element and vaporized from the side surface portion extending in the longitudinal direction of the wick structure. The vaporized vapor moves to the heat radiation side in the heat pipe. On the heat radiation side, the vapor is cooled by heat radiation and liquefied. The liquid working medium moves toward the heat generating body in the wick structure by capillary action. Thereby, heat is transferred from the heat generating element side to the heat radiating side (see, for example, international publication No. WO 2017/115771).
However, when the heat pipe is thinned in the vertical direction as described above, the area of the side surface portion of the wick structure is reduced. Therefore, the working member is less likely to evaporate, and the heat transfer efficiency may be reduced.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a thin heat pipe with high heat transfer efficiency.
An exemplary heat pipe of the present invention includes a tubular container in which a working medium and a porous wick structure for transporting the working medium are accommodated in an internal space. The container has a bottom wall portion and an upper wall portion that are vertically opposed to each other in a cross section perpendicular to an extending direction that is a direction in which the container extends, and a pair of side wall portions. The side wall portions are connected to both side end portions of the bottom wall portion and both side end portions of the upper wall portion, respectively. The wick structure has a lower wick structure and a convex wick structure. The lower wick structure is formed in contact with the bottom wall portion, and the upper surface thereof is disposed facing the internal space. The convex wick structure protrudes upward from the upper surface of the lower wick structure, and has a width in a direction orthogonal to the vertical direction and the extending direction that is narrower than the width of the lower wick structure, and supports the upper wall portion.
In the above embodiment, the wick structure has an upper wick structure formed in contact with the upper wall portion and arranged such that the lower surface faces the internal space, and the convex wick structure is in contact with a part of the lower surface of the upper wick structure.
In the above embodiment, the wick structure includes a pair of side wick structures extending upward from both side ends of the lower wick structure along the side wall portions and connected to both side ends of the upper wick structure.
In the above embodiment, the lower wick structure and the convex wick structure are integrally formed.
In the above embodiment, the convex wick structure is in contact with the lower surface of the upper wall portion.
In the above embodiment, the wick structure includes a pair of side wick structures extending upward from both side ends of the lower wick structure along the side wall portions and connected to both side ends of the upper wick structure.
In the above embodiment, the upper end portion of the side-wick structure is formed to be spaced radially inward from the side wall portion.
In the above embodiment, the convex wick structure extends in the extending direction of the container.
In the above embodiment, a plurality of convex wick structures are arranged at intervals in the extending direction of the container.
In the above embodiment, a plurality of convex-portion wick structures are arranged in a direction in which a pair of side wall portions face each other.
According to the present invention, a heat pipe having a reduced thickness and high heat transfer efficiency can be provided.
The above and other features, elements, steps, features and advantages of the present invention will be more clearly understood from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
Drawings
Fig. 1 is a cross-sectional view showing a schematic structure of a heat pipe according to an exemplary embodiment of the present invention.
Fig. 2 is a cross-sectional view schematically showing a heat pipe according to an exemplary embodiment of the present invention.
Fig. 3 is an explanatory view for explaining a method of manufacturing a heat pipe according to an exemplary embodiment of the present invention.
Fig. 4 is a sectional view schematically showing a heat pipe according to an exemplary embodiment of the present invention.
Fig. 5 is an explanatory view for explaining a method of manufacturing a heat pipe according to an exemplary embodiment of the present invention.
Fig. 6 is a cross-sectional view schematically showing a heat pipe according to an exemplary embodiment of the present invention.
Fig. 7 is an explanatory view for explaining a method of manufacturing a heat pipe according to an exemplary embodiment of the present invention.
Fig. 8 is a cross-sectional view schematically showing a heat pipe according to a modification of the present invention.
Fig. 9 is a cross-sectional view schematically showing a heat pipe according to a modification of the present invention.
Detailed Description
Hereinafter, a heat pipe 1 as a heat conductive member according to an exemplary embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, an XYZ coordinate system is appropriately shown as a 3-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction represents the vertical direction (i.e., the vertical direction), + Z direction is the upward direction (the opposite side to the direction of gravity), and-Z direction is the downward direction (the direction of gravity). The Z-axis direction is also a facing direction of the bottom wall 11 and the upper wall 12, which will be described later. The X-axis direction is a direction orthogonal to the Z-axis direction, and one direction and the opposite direction are the + X direction and the-X direction, respectively. The Y-axis direction is a direction orthogonal to both the Z-axis direction and the X-axis direction, and the one direction and the opposite direction are the + Y direction and the-Y direction, respectively.
< first embodiment >
(1. Structure of Heat pipe)
Fig. 1 is a sectional view showing a schematic structure of a heat pipe 1 according to an embodiment, and fig. 2 is a sectional view schematically showing the heat pipe 1. Fig. 2 shows a cross section perpendicular to the extending direction (X-axis direction) which is the direction in which the heat pipe 1 extends. The heat pipe 1 is a heat conductive member that transports heat of the heat generating body H. Examples of the heat generating element H include an electronic component that generates heat and a substrate on which the electronic component is mounted. The heat generating body H is cooled by heat transfer by the heat pipe 1. The heat pipe 1 is mounted on an electronic device having a heat generating element H, such as a smartphone or a notebook personal computer.
The heat pipe 1 includes a heated portion 101 and a heat radiating portion 102. The heated portion 101 is disposed in contact with the heating element H, for example, and is heated by heat generated by the heating element H. The heat radiating section 102 radiates heat of the working medium 30, which will be described later, heated by the heating section 101 to the outside. In order to improve heat dissipation, the heat dissipation portion 102 is thermally connected to a heat exchange unit (not shown) such as a heat sink or a heat sink.
The heat pipe 1 includes a container 10, a working medium 30, and a wick structure 20. The heated portion 101 is formed by a part of the container 10. The heat sink 102 is formed from another portion of the container 10.
(2. Structure of Container)
The container 10 is formed in a flat tubular shape and made of metal such as copper. The container 10 may be formed of a metal other than copper. The container 10 may be formed by plating the inner peripheral surface with copper and combining with another metal. Examples of metals other than copper include stainless steel.
The container 10 has a bottom wall 11, an upper wall 12, and a pair of side walls 13. The bottom wall 11 and the upper wall 12 are flat and arranged to face each other in the Z-axis direction. That is, the container 10 has a bottom wall portion 11 and an upper wall portion 12 that face each other in the vertical direction (Z-axis direction) in a cross section perpendicular to the extending direction (X-axis direction), and a pair of side wall portions 13 that connect both side end portions of the bottom wall portion 11 and both side end portions of the upper wall portion 12, respectively.
The heating element H (see fig. 1) is in contact with the lower surface of the bottom wall 11. By forming the bottom wall 11 in a flat shape, the contact area between the lower surface of the bottom wall 11 and the heating element H can be increased. Therefore, the heat generated by the heating element H is efficiently transmitted to the bottom wall portion 11. The shape of the bottom wall 11 may be changed according to the shape of the heating element H.
The side wall portions 13 respectively connect both side end portions of the upper wall portion 12 and both side end portions of the bottom wall portion 11. The upper end and the lower end of the side wall portion 13 are formed to be convexly curved radially outward. The thickness of the container 10 in the Z-axis direction is, for example, 1mm to 3 mm.
The container 10 has an internal space 10a surrounded by a bottom wall 11, an upper wall 12, and a side wall 13. The working medium 30 and the wick structure 20 are disposed in the internal space 10 a. The liquefied working medium 30 moves through the porous wick structure 20. The vaporized working medium 30 moves in the internal space 10 a. That is, the tubular container 10 accommodates the working medium 30 and the porous wick structure 20 for transporting the working medium 30 in the internal space 10 a.
The internal space 10a is a closed space and is maintained in a reduced pressure state, for example, in which the pressure is lower than the atmospheric pressure. When the internal space 10a is in a reduced pressure state, the working medium 30 stored in the internal space 10a is easily evaporated. The working medium 30 is, for example, water, but may be other liquid such as alcohol. The liquid-absorbing core structure 20 is made of a porous sintered copper body that transports the working medium 30.
(3. Structure of wick Structure)
The wick structure 20 is porous and has a void portion (not shown) that forms a flow path of the working medium 30. The wick structure 20 extends in the extending direction (X-axis direction) of the container 10. The thickness of wick structure 20 in the radial direction from the inner circumferential surface of container 10 is 0.02mm to 0.1 mm.
The wick structure 20 includes a lower wick structure 21, a pair of side wick structures 23, and a convex wick structure 24. Lower wick structure 21 is formed in contact with bottom wall 11, and its upper surface is disposed facing internal space 10 a. Side wick structures 23 extend upward from both side ends of bottom wall 11 along side wall 13. Convex wick structure 24 protrudes upward from the upper surface of lower wick structure 21 and contacts the lower surface of upper wall 12. Thus, convex wick structure 24 supports upper wall 12. In addition, in the present specification, "facing" the internal space 10a means "opposing" the internal space 10 a.
Upper end portion 23a of side wick structure 23 is formed to be spaced radially inward from side wall portion 13. When the upper wall portion 12 of the container 10 is pressed downward and the side wall portion 13 is curved to be convex outward, the upper inner surface of the side wall portion 13 is supported in contact with the upper end portion 23 a. This ensures a steam flow path, and reduces a decrease in heat transfer efficiency.
Lower liquid-absorbent core structure 21 and side liquid-absorbent core structure 23 are formed by, for example, spraying and applying metal powder 40 (see fig. 3) containing fine copper particles, copper bodies, and resin to the inner circumferential surface of container 10, and then firing the applied metal powder. In the present specification, "coating" means that the metal powder 40 is attached to the inner peripheral surface of the container 10. In addition to the spray coating method, the metal powder 40 may be directly coated. Further, a mandrel bar may be inserted into the container 10, and the metal powder 40 may be filled in a gap formed between the outer peripheral surface of the mandrel bar and the inner peripheral surface of the container 10. At this time, the metal powder 40 can be attached to the inner peripheral surface of the container 10 by pulling out the plug from the container 10 after the metal powder 40 is filled.
The fine copper particles are particles in which a plurality of copper atoms are aggregated or bonded. The particle diameter of the micro copper particles is more than 1 μm and less than 1 mm. The fine copper particles are porous, for example.
The copper body is a molten copper body formed by sintering, melting and solidifying submicron copper particles smaller than the micro copper particles. The submicron copper particle is a particle in which a plurality of copper atoms are aggregated or bonded. The submicron copper particles before melting have a particle diameter of 0.1 μm or more and less than 1 μm.
The resin is a volatile resin that volatilizes at a temperature not higher than the melting point of copper constituting the fine copper particles and the copper bodies. Examples of the volatile resin include cellulose resins such as methyl cellulose and ethyl cellulose, acrylic resins, butyral resins, alkyd resins, epoxy resins, and phenol resins. Among them, acrylic resins having high thermal decomposition property are preferably used.
(4. method for manufacturing Heat pipe)
Fig. 3 is an explanatory view for explaining a method of manufacturing the heat pipe 1. The method for manufacturing the heat pipe 1 includes a coating step, a metal powder heating step, a container pressing step, and a sealing step.
(4-1. coating Process)
In the coating step, the metal powder 40 is applied by spraying to a predetermined range in the circumferential direction of the lower portion of the inner peripheral surface of the container 10 having a right circular tube shape with a uniform thickness of 0.02mm to 0.1mm (see fig. 3). After the metal powder 40 is applied, the copper wire 41 is disposed at the lower end of the container 10. The metal powder 40 includes metal particles and volatile resin. The metal particles comprise a plurality of micro-copper particles and a plurality of sub-micro-copper particles as described above.
(4-2. Metal powder heating Process)
In the metal powder heating step, the metal powder 40 and the copper wire 41 applied in the application step are put into a heating furnace together with the container 10 and heated. The heating temperature in this case is, for example, 400 ℃ and the heating time is, for example, 1 hour. The resin contained in the metal powder 40 is volatilized by heating the metal powder 40 and the copper wire 41, and the submicron copper particles are melted by sintering and fired to be solidified. Thereby, a porous wick structure 20 is formed on the inner circumferential surface of the container 10.
(4-3. Container punching Process)
In the container pressing step, the liquid-absorbent core structure 20 is placed below in the metal powder heating step, and the container 10 is pressed while being sandwiched from the Z-axis direction (vertical direction). Thus, the container 10 is formed flat in a cross section perpendicular to the extending direction, and forms a bottom wall portion 11, an upper wall portion 12, and a side wall portion 13. At this time, convex wick structure 24 contacts upper wall 12 and supports upper wall 12. Upper end portion 23a of side wick structure 23 is formed so as to be separated from side wall portion 13 without following the curvature of side wall portion 13 when container 10 is pressed (see fig. 2). Therefore, the upper end portion 23a separated from the side wall portion 13 to the radially inner side can be easily formed.
(4-4. sealing Process)
In the sealing step, the wick structure 20 inside the container 10 is sealed together with the working medium 30. Thereby, the heat pipe 1 is completed.
(5. action of Heat pipe)
In the heat pipe 1 having the above-described configuration, heat generated by the heating element H is heated by the heating unit 101. When the temperature of the heated portion 101 increases, the working medium 30 stored in the internal space 10a of the container 10 is vaporized. The vaporized steam moves toward the heat radiation portion 102 side in the internal space 10 a. In the heat radiating section 102, the vapor is cooled by heat radiation and liquefied. The liquefied working medium 30 moves toward the heated portion 101 in the wick structure 20 by capillary action. In fig. 1, the flow of the vapor after the vaporization of the working medium 30 is indicated by black arrows, and the flow of the liquid working medium 30 is indicated by hollow arrows. As described above, the working medium 30 moves with a change in state, and heat is continuously transferred from the heated target portion 101 side to the heat radiating portion 102 side.
< second embodiment >
Next, a second embodiment of the present invention will be explained. Fig. 4 is a cross-sectional view schematically showing a heat pipe 1 according to a second embodiment. For convenience of explanation, the same reference numerals are given to the same parts as those of the first embodiment shown in fig. 1 to 3. In the second embodiment, the shape of the wick structure 20 is different from that of the first embodiment. The other portions are the same as those of the first embodiment.
The wick structure 20 is formed over the entire circumference of the inner surface of the container 10, and includes an upper wick structure 22. That is, the upper wick structure 22 is formed in contact with the upper wall 12, and the lower surface thereof is disposed facing the internal space 10 a. The side wick structures 23 are connected to both side ends of the upper wick structure 22.
The convex wick structures 24 are formed to have a width in the Y-axis direction smaller than the width of the lower wick structure 21 and the upper wick structure 22. As a result, the vaporization surfaces 21a and 22a of the working medium 30 are formed on the upper surface of the lower wick structure 21 and the lower surface of the upper wick structure 22 at portions not in contact with the convex wick structure 24. The vaporizing surfaces 21a, 22a are disposed facing the internal space 10a, and the area of the vaporizing surfaces 21a, 22a is not changed even when the container 10 is thinned in the Z-axis direction. Therefore, the heat pipe 1 can be made thinner and the decrease in heat transfer efficiency can be further reduced.
By forming the wick structure 20 over the entire circumference of the inner surface of the container 10, the container 10 is reinforced over the entire circumference. This makes the container 10 less likely to be deformed by the pressing in the Z-axis direction.
Fig. 5 is an explanatory view for explaining a method of manufacturing the heat pipe 1, and in the coating step, the metal powder 40 is coated on the entire circumference of the inner circumferential surface of the container 10. This makes it possible to easily form the lower wick structure 21, the upper wick structure 22, and the convex wick structure 24 in the container pressing step.
< third embodiment >
Next, a third embodiment of the present invention will be explained. Fig. 6 is a cross-sectional view schematically showing a heat pipe 1 according to a third embodiment. For convenience of explanation, the same reference numerals are given to the same parts as those of the second embodiment shown in fig. 4 and 5. In the third embodiment, the shape of the wick structure 20 is different from that of the first embodiment. The other portions are the same as those of the second embodiment.
The wick structure 20 is integrally formed with a convex wick structure 24 and a lower wick structure 21.
Fig. 7 is an explanatory view for explaining a method of manufacturing the heat pipe 1, in which the metal powder 40 is applied to a lower end portion of the container 10 to a large thickness in the radial direction in the application step. Thereby, the lower end of the metal powder 40 is formed to protrude upward. This allows convex wick structure 24 to be easily formed by metal powder 40, and the manufacturing cost of heat pipe 1 can be reduced.
In addition, the convex wick structure 24 and the lower wick structure 21 of the wick structure 20 according to the first embodiment may be integrally formed in the same manner as in the present embodiment.
While the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications can be made without departing from the spirit of the present invention. The above embodiments and modifications thereof can be combined as appropriate.
Fig. 8 and 9 are cross-sectional views schematically showing heat pipes according to modified examples of the present invention. As shown in fig. 8, the wick structure 20 may be formed without the side wick structures 23. As shown in fig. 9, a plurality of convex-portion wick structures 24 may be arranged in the Y-axis direction (the facing direction of the pair of side wall portions 13). Further, a plurality of convex-portion wick structures 24 may be arranged at intervals in the extending direction of container 10.
The heat pipe of the present invention can be used as a substrate mounted on an electronic device or a heat dissipating member for an electronic component, for example.
Claims (10)
1. A heat pipe comprising a tubular container for containing a working medium and a porous wick structure for transporting the working medium in an internal space,
the container has:
a bottom wall portion and an upper wall portion that are vertically opposed to each other in a cross section perpendicular to an extending direction that is a direction in which the container extends; and
a pair of side wall portions connecting both side end portions of the bottom wall portion and both side end portions of the upper wall portion, respectively,
it is characterized in that the preparation method is characterized in that,
the liquid absorption core structure comprises:
a lower liquid-absorbing core structure formed in contact with the bottom wall portion, an upper surface of the lower liquid-absorbing core structure being disposed so as to face the internal space; and
and a convex wick structure that protrudes upward from an upper surface of the lower wick structure, has a width in a direction orthogonal to the vertical direction and the extending direction smaller than the width of the lower wick structure, and supports the upper wall portion.
2. A heat pipe according to claim 1,
the wick structure has an upper wick structure formed in contact with the upper wall and arranged with a lower surface facing the internal space,
the convex wick structure is in contact with a portion of the lower surface of the upper wick structure.
3. A heat pipe according to claim 2,
the wick structure includes a pair of side wick structures extending upward from both ends of the lower wick structure along the side wall portions and connected to both ends of the upper wick structure.
4. A heat pipe according to claim 1,
the lower wick structure and the convex wick structure are integrally formed.
5. A heat pipe according to claim 2,
the convex wick structure is in contact with the lower surface of the upper wall.
6. A heat pipe according to claim 5,
the wick structure includes a pair of side wick structures extending upward from both ends of the lower wick structure along the side wall portions and connected to both ends of the upper wick structure.
7. A heat pipe according to claim 6,
the upper end portion of the side wick structure is formed to be radially inwardly spaced from the side wall portion.
8. A heat pipe according to claim 1,
the convex wick structure extends in the direction of extension of the container.
9. A heat pipe according to claim 1,
the plurality of convex wick structures are arranged at intervals in the extending direction of the container.
10. A heat pipe according to claim 8 or 9,
the convex wick structures are arranged in a plurality in a row in a direction in which the pair of side walls face each other.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-088406 | 2020-05-20 | ||
| JP2020088406A JP2021181873A (en) | 2020-05-20 | 2020-05-20 | heat pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215647910U true CN215647910U (en) | 2022-01-25 |
Family
ID=78606380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121092944.8U Active CN215647910U (en) | 2020-05-20 | 2021-05-20 | Heat pipe |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2021181873A (en) |
| CN (1) | CN215647910U (en) |
-
2020
- 2020-05-20 JP JP2020088406A patent/JP2021181873A/en active Pending
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2021
- 2021-05-20 CN CN202121092944.8U patent/CN215647910U/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2021181873A (en) | 2021-11-25 |
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