CN110710342A

CN110710342A - Thin plate type heat pipe and method for manufacturing the same

Info

Publication number: CN110710342A
Application number: CN201880035514.7A
Authority: CN
Inventors: 尹护燮
Original assignee: Cgi Corp
Current assignee: Cgi Corp
Priority date: 2017-05-29
Filing date: 2018-05-29
Publication date: 2020-01-17
Anticipated expiration: 2038-05-29
Also published as: KR101826341B1; CN110710342B; WO2018221939A1

Abstract

The invention provides a thin plate type heat pipe and a manufacturing method thereof, comprising the following steps: cutting a metal plate to manufacture an upper raw plate and a lower raw plate; stamping the upper original plate, forming a plurality of bulges on the upper original plate, and forming throttling channels among the bulges; stamping at least one of the upper original plate and the lower original plate to form a core space; arranging a fiber core in the core space, wherein the fiber core is formed by aramid fibers modified to be hydrophilic; bonding the upper and lower original plates to form a housing in a state where the fiber core is disposed; and injecting the working fluid flowing in the throttling channel into the shell through an injection port, and sealing the injection port after the interior of the shell is vacuumized through the injection port.

Description

Thin plate type heat pipe and method for manufacturing the same

Technical Field

The present invention relates to a thin plate type heat pipe and a method for manufacturing the same.

Background

Generally, a heat pipe is a heat transfer mechanism having thermal conductivity several tens times higher than that of a thermally conductive metal. A thin plate-shaped heat pipe is recently developed to cool a heat dissipating part having a large area such as a CPU of a computer, and is generally manufactured in a shape shown in fig. 1 (issued patent No. 10-0698462).

As shown in fig. 1, the thin plate-shaped heat pipe 101 is composed of an outer case 103 and a core structure 105, the outer case 103 is formed by bonding an upper plate 131 and a lower plate 132, and the core structure 105 is formed in the case 103 by a support structure 107 such as a mesh and a working fluid contained in the case 103.

Since the heat pipe 101 uses a fiber aggregate as the wick structure 105, it can be made thinner than a conventional heat pipe in which a wick is made of sintered metal or the like. However, since the core structure 105 is made of cotton fabric or the like, the core force is weak or almost lost, and there is a problem that the core structure cannot function as a core.

Further, the fiber core structure 105 does not have sufficient strength, and the upper plate 131 and the lower plate 132 do not have sufficient strength as thin plates, and thus the overall strength of the heat pipe 101 is low.

Further, if an organic solvent having a low vaporization point, such as acetone, is used as the working fluid, the working fluid heated in the evaporation portion is easily vaporized, and the heated working fluid is easily vaporized, so that the entire length of the heat pipe 101 cannot be made sufficiently longer than when water is used as the working fluid. Accordingly, since the length and width cannot be increased while the thickness of the case 103 is reduced, there is a problem that the heat pipe 101 cannot be made thin and large.

Disclosure of Invention

(problem to be solved)

The present invention has been made to solve the problems of the conventional thin plate heat pipe, and an object of the present invention is to provide a thin plate heat pipe and a method for manufacturing the same, which can suppress early vaporization of a working fluid and can make the heat pipe thin and large.

Another object of the present invention is to provide a thin plate heat pipe and a method of manufacturing the same, in which the thin plate heat pipe is enlarged and the evaporation portion is disposed in a reverse direction with the condensation portion being located below the evaporation portion.

Another object of the present invention is to provide a thin plate heat pipe and a method of manufacturing the same, the thin plate heat pipe including: even if it is periodically and long-term exposed to a high-temperature environment to transfer heat from high temperature to low temperature, damage or deformation of the fiber core due to heat can be minimized.

Another object of the present invention is to provide a thin plate heat pipe and a method of manufacturing the same, which can maintain strength even when the outer shell plate has a reduced wall thickness.

(means for solving the problems)

In order to achieve the above object, a method for manufacturing a thin plate type heat pipe according to an aspect of the present invention may include: cutting a metal plate to manufacture an upper raw plate and a lower raw plate; stamping the upper original plate, forming a plurality of bulges on the upper original plate, and forming throttling channels among the bulges; stamping at least one of the upper original plate and the lower original plate to form a core space; arranging a fiber core in the core space, wherein the fiber core is formed by aramid fibers modified to be hydrophilic; bonding the upper and lower original plates to form a housing in a state where the fiber core is disposed; and injecting the working fluid flowing in the throttling channel into the shell through an injection port, and sealing the injection port after the interior of the shell is vacuumized through the injection port.

The step of forming a core space by press-working at least one of the upper and lower original plates may include forming a recessed space for accommodating the fiber core in at least one of the upper and lower original plates.

Here, the step of arranging a fiber core composed of an aramid fiber modified to be hydrophilic in the core space may include heat-treating the aramid fiber to be modified to be hydrophilic.

Here, the step of injecting the working fluid flowing through the throttling passage into the case through an injection port, and sealing the injection port after vacuuming the inside of the case through the injection port may include externally heating the working fluid injected into the case before sealing the injection port, and removing air contained in the working fluid.

The thin plate type heat pipe manufacturing method of another aspect of the present invention may include the steps of: cutting a metal plate into a size and a shape corresponding to the outer tube of the shell to manufacture an upper original plate and a lower original plate; stamping the upper original plate, forming a plurality of bulges on the upper original plate, and forming throttling channels among the bulges; manufacturing an edge area of one of the upper raw plate and the lower raw plate by using an attaching flange through stamping; joining one of the attachment flanges of the upper and lower stock sheets to the other edge region of the upper and lower stock sheets to form the housing; and injecting the working fluid flowing in the throttling channel into the shell through an injection port, and sealing the injection port after the interior of the shell is vacuumized through the injection port.

Here, joining one of the upper and lower raw plates to the other edge region of the upper and lower raw plates may include joining one of the upper and lower raw plates to the other edge region of the upper and lower raw plates by brazing or welding.

Here, the method may further include the steps of: stamping at least one of the upper raw plate and the lower raw plate to form a core space; and a fiber core made of aramid fiber is disposed in the core space.

Here, the step of disposing a fiber core composed of an aramid fiber in the core space may include heat-treating the aramid fiber so as to have hydrophilicity.

The thin plate type heat pipe of another aspect of the present invention may include: an upper plate provided with a plurality of protrusions and throttle passages formed between the plurality of protrusions; a lower plate configured corresponding to the upper plate so as to face the plurality of protrusions and forming a working space in which the working fluid works in the throttling passage together with the upper plate; a core space recessed in at least one of the upper plate and the lower plate and located in the working space; and a porous fiber core disposed in the core space and in contact with the plurality of protrusions.

Here, the upper plate is formed with the plurality of projections and the throttle passage on one surface of the original plate by press working the original plate.

Here, the fiber core may include aramid fibers modified to be hydrophilic.

(Effect of the invention)

In the thin plate type heat pipe and the method of manufacturing the same according to the present invention, since the plurality of projections are formed to be uniformly projected on the inner surface of the outer plate of the casing, i.e., the upper plate and/or the lower plate, the mechanical strength of the outer plate which has to be thinned due to the thinning of the heat pipe can be further enhanced.

In addition, even if an organic solvent having a low vaporization point such as acetone is used as the working fluid, since a plurality of projections are projected on the inner surface of the case as described above, early vaporization of the working fluid can be suppressed by these projections, and therefore, not only water that does not vaporize early, but also the length and width can be increased more than the thickness of the case even if an organic solvent that vaporizes earlier than water is used as the working fluid, and therefore, not only the thinning of the heat pipe but also the upsizing can be realized.

Further, since the plurality of protrusions are provided in the heat pipe together with the fiber core as described above, an organic solvent can be used as the working fluid in addition to water in the heat pipe which is thin and large. Further, the heat pipe may be used in a reverse arrangement state in which the evaporation portion is arranged in the upper and condensation portions.

Further, since aramid fibers can be used as the material of the fiber core, the thinning of the heat pipe can be accelerated. Further, even if the heat pipe is periodically and long-term exposed to a high-temperature environment, damage or deformation of the core fiber due to heat can be minimized.

Drawings

Fig. 1 is an exploded perspective view of a conventional heat pipe.

Fig. 2 is a block diagram sequentially showing a heat pipe manufacturing method according to an embodiment of the present invention.

Fig. 3 is a view schematically showing in sequence a method of manufacturing the heat pipe of fig. 2.

Fig. 4 is a schematic sectional view showing a heat pipe finally completed by the manufacturing method of fig. 3.

Fig. 5 is a view showing the assembly steps of the original plates in the heat pipe manufacturing method according to another embodiment of the present invention, respectively, in accordance with the embodiment.

Fig. 6 is a diagram showing the heat pipe assembled according to fig. 5 in a separate manner according to an embodiment.

Detailed Description

Hereinafter, a thin plate type heat pipe and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 2, the method for manufacturing a heat pipe of the present invention generally includes: a cutting step S10, a pressing step S20, an assembling step S30, and a finalizing step S40.

As shown in fig. 2, the cutting step S10 is a step of cutting a pair of original plates P1 and P2 (an upper original plate P1 and a lower original plate P2) from the metal plate material M. As shown in fig. 3, the pair of original plates P1, P2 are cut into appropriate lengths and shapes from a metal plate material M that is generally stored in a rolled shape, in accordance with the

outer plates

31, 32 that constitute the outer shell 3. As shown in fig. 3 and 4, one P1 of the pair of original plates P1 and P2 is the upper plate 31, and the other P2 is the lower plate 32. Thus, one P1 among the original plates P1, P2 is cut to have a size and a shape suitable as the upper plate 31, for example, and the other P2 is cut to have a size and a shape suitable as the lower plate 32, for example.

As shown in fig. 2, the pressing step S20 is a step of press-working one side of the pair of original plates P1 and P2 cut in the cutting step S10. For example, as shown in fig. 3, the upper plate 31 of the original plates P1 and P2 is pressed to form a plurality of protrusions 5 as shown in fig. 3 and 4.

As shown in fig. 3 and 4, the plurality of projections 5 formed to project from the upper plate 31 serve as a means for suppressing vaporization of the working fluid heated in the evaporation portion E. The plurality of projections 5 project across the working space S inside the housing 3, and are regularly arranged while forming a shape such as a lattice within the working space S. Therefore, the plurality of protrusions 5 form the throttle passage T in the working space S, allowing the working fluid to flow in all directions, front, rear, left, and right on the drawing. At this time, while the working fluid flows through the throttle passage T, the working fluid is inhibited from vaporizing by the projection 5. That is, although the temperature rises, the working fluid particles are pressed by the plurality of projections 5 and are suppressed from expanding. At this time, the plurality of protrusions 5 may be arranged in various shapes. On the other hand, the upper plate 31 is formed with a sticking flange 33 having a stepped edge portion by press working, and an inlet 35 for connecting the working space S and the outside is formed in a portion on the sticking flange 33 side.

The other of the pair of original plates P1, P2, the lower plate 32, may be press-formed into various shapes, which are the same as or different from the upper plate 31, as required. That is, the lower plate 32 may be formed to have a plurality of protrusions in the same manner as the upper plate 31, and the entire central region may be formed as a concave space in addition to the edge region to be the attachment flange.

As shown in fig. 2, the assembling step S30 is a step of assembling the

outer plates

31, 32, i.e., the upper plate 31 and the lower plate 32, produced by selectively press-working the original plates P1, P2 in the above-described pressing step S20. For example, as shown in fig. 3 and 4, the housing 3 is assembled by joining a press-worked upper plate 31 and a selective press-worked lower plate 32. Here, the selective press working of the lower plate 32 means the same press working as the upper plate 31 or a different press working when the lower plate 32 is not press-worked or press-worked as necessary. On the other hand, the upper plate 31 and the lower plate 32 are joined by various metal joining methods such as brazing and welding, for example, the attachment flange 33 and the edge region of the lower plate 32.

As shown in fig. 2, the ending step S40 is a step of ending the heat pipe by the ending process for the case 3 formed by joining the

outer plates

31 and 32 to each other in the assembling step S30. As shown in fig. 3, the working fluid is injected into the working space S formed inside the case 3, the working space S is vacuumed after the injection, and then the case 3 is sealed, thereby completing a series of heat pipe manufacturing processes.

For this purpose, the casing 3 is filled with the working fluid WF from the outside into the working space S through the injection port 35 or the injection port 35 and a filling tube (fill) 37 detachable from the injection port 35. When the injection of the working fluid is completed, the working space S is subjected to a vacuum process by a vacuum source connected from the outside through the injection port 35. Finally, the injection port 35 is sealed after the completion of the vacuumization of the working space S, and the housing 3 is subjected to a finishing process.

At this time, the working fluid is a heat transfer medium, and transfers heat applied to the evaporation portion E at one side end of the housing 3 to the condensation portion C at the other side end to be discharged. Specifically, the working fluid is vaporized by heat applied to the evaporation portion E, then cooled and condensed in the condensation portion C, and returned to the evaporation portion E. Accordingly, the working fluid functions to release heat continuously removed from the heat source on the evaporation portion E side to the outside air through the condensation portion C. In this case, water having a relatively large contact angle may be used as the working fluid. In contrast to this, organic solvents having a contact angle smaller than water, which may be selected among organic solvents such as acetone, HFC, HFE, HFO series, may also be used as the working fluid.

On the other hand, the working fluid injected into the working space S may be heated from the outside of the housing 3 in a state where the injection port 35 is not sealed before and after completion of the vacuum treatment or at the same time point. Accordingly, the impurity gas such as air contained in the case 3 is released and removed in the form of bubbles, and the degree of vacuum of the case 3 can be further increased after the injection port 35 is sealed.

In addition, as shown in fig. 5 and 6, the heat pipe 20 may further include a fiber core 7. To this end, as another embodiment, as shown in fig. 5 and 6, the present invention further includes a process for adding the fiber core 7.

As shown in fig. 5, in the punching step S20, the pair of original plates P1, P2 may form a core space W for providing the fiber core 7 only on either one side or both sides of the pair of original plates. For this reason, as shown in fig. 5(a), for example, only the upper plate 31 may be press-worked, and a plurality of bosses 5 and core spaces W may be formed in parallel on the upper plate 31. Accordingly, the lower plate 32 is sent to the assembly process in a state of being cut at the cutting step S10. In such a case, the overall thickness of the heat pipe 20 may be minimized. Further, as shown in fig. 5(b), the projections 5 are formed on the upper plate 31, the core space W is formed on the lower plate 32, and the projections 5 and the core space W may face each other. In this case, the heat pipe takes the most stable shape in profile. Further, as shown in fig. 5(c), the boss 5 and a part of the core space W may be formed in the upper plate 31, the remaining part of the core space W may be formed in the lower plate, and the entire core space W may be formed by assembling the upper plate 31 and the lower plate 32. In this case, the core space W is maximized in volume, and thus, the heat dissipation efficiency can be maximized. Further, by forming a part of the core space W in each of the upper plate 31 and the lower plate 32, which are thin plates, it is possible to prevent the upper plate 31 or the lower plate 32 from being damaged due to the formation of the large core space W only in one side of the upper plate 31 and the lower plate 32.

On the other hand, as shown in fig. 5 and 6, before the pair of

outer plates

31, 32 are joined in the assembling step S30, the fiber core 7 is arranged in the core space W formed in the upper plate 31 and/or the lower plate 32 in the above-described pressing step S20.

Here, the fiber core 7 is accommodated in the working space S of the housing 3 together with the working fluid, and functions to return the working fluid condensed at the condensation portion C to the evaporation portion E by capillary force. That is, since the fiber core 7 uses porous fibers, capillary force is generated to smoothly move the working fluid condensed in the condensing portion C to the evaporating portion E. Accordingly, when the fiber core 7 is applied, even if the thin plate type heat pipe 1 is in a state of being arranged in a reverse direction, that is, the evaporation portion E is arranged upward, the condensation portion C is arranged downward, and a flexible heat transfer performance can be exhibited.

The fiber core 7 as described above is preferably formed in a wide and thin sheet shape, and for this reason, an aramid material is preferably used. The aramid material is made of aramid fiber having heat resistance and high tensile strength, and has a porous internal structure, and thus generates a strong capillary force to smoothly move the working fluid condensed at the condensing portion C to the evaporation portion E. In particular, kevlar (r) fiber, which is one of aramid fibers, is mostly composed of aromatic (aromatic) that is stronger than alkyl (alkyl) and is fire-resistant, and therefore is also widely used for special applications such as bulletproof. For kevlar fibres, the surface is very stable because of the special conditions of the manufacturing process to make very fine or superfine fibres (fibers).

However, when a liquid having a large contact angle such as water is used as the working fluid for the fiber core 7, the aramid fiber should be made hydrophilic. For this reason, the hydrophilic modification treatment of the hydrophobic coating component is removed by exposing the fiber core 7 at a high temperature for a predetermined time, thereby eliminating the hydrophobicity of the aramid fiber. However, when the organic solvent is used as the working fluid, the aramid fiber does not need to have hydrophilicity, and therefore, the fiber core 7 does not need to be modified separately.

If the same finish-off process as the finish-off step described above is performed on the upper plate 31 and the lower plate 32 in the state where the fiber cores 7 prepared through such a process are arranged, the thin plate type heat pipes 20 of various arrangement structures as shown in fig. 6 can be assembled and produced.

Now, the function of the thin plate type heat pipe 20 manufactured by the preferred embodiment of the present invention is explained as follows.

When the evaporation portion E of the heat pipe 20 shown in fig. 6 is exposed to the heat source and the condensation portion C is exposed to the outside air, the working fluid in the evaporation portion E takes heat of the heat source while evaporating, and the vaporized working fluid moves to the condensation portion C. Therefore, the heated working fluid reaches the condensation portion C through the throttle passage T between the plurality of projections 5 shown in fig. 3, is liquefied after releasing heat into the outside air, and returns to the evaporation portion E.

As described above, the working fluid is inhibited from being vaporized by the plurality of projections 5 while passing through the throttle passage T in the heated state, and therefore, even if an organic solvent having a low vaporization point such as acetone is used, the distance between the evaporation portion E and the condensation portion C can be sufficiently set to be long, which corresponds to the case of using water having a high vaporization point as the working fluid.

Finally, the process of the working fluid liquefied in the condensation unit C moving to the evaporation unit E through the fiber core 7 and evaporating again is repeated, and further, the heat transfer from the heat source and the release into the outside air are enabled. In this process, the fiber core 7 may function to evaporate the working fluid at the evaporation portion E, to transfer the condensed working fluid to the evaporation portion E by capillary force, and also to function as a passage (path road) of the vaporized gas.

The thin plate type heat pipe and the method of manufacturing the same as described above are not limited to the structure and operation of the above-described embodiments. The above-described embodiments may be variously modified in combination with all or a part of the embodiments.

Industrial applicability

The invention can be used in the field of manufacturing of thin-plate heat pipes.

Claims

1. A manufacturing method of a thin plate type heat pipe comprises the following steps:

cutting a metal plate to manufacture an upper raw plate and a lower raw plate;

stamping the upper original plate, forming a plurality of bulges on the upper original plate, and forming throttling channels among the bulges;

stamping at least one of the upper original plate and the lower original plate to form a core space;

arranging a fiber core in the core space, wherein the fiber core is formed by aramid fibers modified to be hydrophilic;

bonding the upper and lower original plates to form a housing in a state where the fiber core is disposed; and

and injecting the working fluid flowing in the throttling channel into the shell through an injection port, and sealing the injection port after the interior of the shell is vacuumized through the injection port.

2. A thin plate type heat pipe manufacturing method according to claim 1,

at least one of the upper and lower original plates is press-worked to form a core space, including the steps of:

at least one of the upper and lower original plates is formed with a recessed space for accommodating the fiber core.

3. A thin plate type heat pipe manufacturing method according to claim 1,

the method comprises the following steps of arranging a fiber core in the core space, wherein the fiber core is formed by aramid fibers modified to be hydrophilic, and the steps comprise the following steps:

heating the aramid fiber to modify the aramid fiber to be hydrophilic.

4. A thin plate type heat pipe manufacturing method according to claim 1,

injecting the working fluid flowing through the throttling channel into the housing through an injection port, and after vacuuming the interior of the housing through the injection port, sealing the injection port, including the steps of:

externally heating the working fluid injected into the housing before sealing the injection port to remove air contained in the working fluid.

5. A manufacturing method of a thin plate type heat pipe comprises the following steps:

cutting a metal plate into a size and a shape corresponding to the outer tube of the shell to manufacture an upper original plate and a lower original plate;

manufacturing an edge area of one of the upper raw plate and the lower raw plate by using an attaching flange through stamping;

joining one of the attachment flanges of the upper and lower stock sheets to the other edge region of the upper and lower stock sheets to form the housing; and

6. A thin plate type heat pipe manufacturing method as set forth in claim 5,

the step of joining one of the attachment flanges of the upper and lower raw plates to the other edge region of the upper and lower raw plates to form the housing includes the steps of:

joining one of the attachment flanges of the upper and lower raw plates to the other edge region of the upper and lower raw plates by brazing or welding.

7. A method of manufacturing a thin plate type heat pipe according to claim 5, further comprising:

stamping at least one of the upper raw plate and the lower raw plate to form a core space; and

a fiber core made of aramid fiber is disposed in the core space.

8. A thin plate type heat pipe manufacturing method as set forth in claim 7,

the step of disposing a fiber core made of aramid fiber in the core space includes the steps of:

the aramid fiber is heat-treated so as to have hydrophilicity.

9. A thin plate type heat pipe comprising:

an upper plate provided with a plurality of protrusions and throttle passages formed between the plurality of protrusions;

a lower plate disposed corresponding to the upper plate so as to face the plurality of protrusions and forming a working space in which the working fluid works in the throttling passage together with the upper plate;

a core space recessed in at least one of the upper plate and the lower plate and located in the working space; and

and a porous fiber core disposed in the core space and in contact with the plurality of protrusions.

10. A thin plate type heat pipe according to claim 9,

through the stamping process to the original plate, the upper plate forms the plurality of bulges and the throttling channel on one surface of the original plate.

11. A thin plate type heat pipe according to claim 9,

the fiber core comprises aramid fibers modified to be hydrophilic.