KR101539445B1 - Thin Type Heat Pipe Manufacturing Method - Google Patents

Abstract

The present invention relates to a method of manufacturing a thin heat pipe, comprising a housing manufacturing step (S10) of manufacturing a plate-like housing (3) by a pair of flat plates (11) and a pair of side walls (13); A working fluid injection step (S20) of injecting a working fluid (F) into the housing (3); And a finishing step (S30) of compressing the injection port (9) of the housing (3) to seal the housing (3), wherein the housing manufacturing step (S10) A semi-finished product molding step (S11) of molding the semi-finished product (10) of the housing (3) to a thickness as much as possible; And a housing molding step (S12) of molding the housing (3) by rolling the semi-finished product (10) molded in the semi-finished product molding step (S11), wherein the semi-finished product The inner peripheral surface of the pair of sidewall bodies 13 is inclined. Accordingly, by reducing the buckling resistance generated when the housing semi-finished product 10 is rolled, the flat plate body 11 as a whole is flattened Thereby providing a heat pipe having a thin and high heat transfer performance.

Description

TECHNICAL FIELD [0001] The present invention relates to a thin-type heat pipe manufacturing method,

The present invention relates to a thin-type heat pipe manufacturing method, and more particularly, to a thin-type heat pipe manufacturing method in which thin-walled heat pipes, which can not be manufactured by extrusion or drawing, To a method of manufacturing a pipe.

Generally, the heat flux is tens or hundreds of times larger than that of a high heat conductive metal such as silver, copper, or aluminum. Therefore, the heat pipe has a very wide range of applications, which is useful in various fields such as cooling of a heat part at a specific position such as a CPU of a computer, recovery of exhaust gas heat, collection of geothermal heat or solar heat Is a heat transfer device that is being used.

The heat pipe is made of a gas-tight solid such as stainless steel, copper, or aluminum, and forms a closed space, that is, a housing, in the form of a tube or the like, to contain a working fluid therein. Therefore, when heat is applied from one side of the housing, the working fluid is evaporated in the internal space of the heating part, and the evaporated steam quickly moves to the other side where heat is not applied and is condensed so that heat of the heating part (evaporating part) heat) to the condenser. At this time, the condensed liquid is returned to the heating section by the capillary force of the wick structure provided inside the housing. Thereafter, the heat transfer cycle is repeated infinitely, so that the heat of the heating section is continuously transferred to the condensation section.

However, in recent years, various miniaturization and thinning of various electronic products such as computers and notebooks to which the heat pipes are applied are required to be small and thin.

However, in the case of a plate heat pipe, which is widely produced in general, the drawing or extrusion process applied when manufacturing a plate-shaped housing is subject to a certain dimensional limitation on the thinning of the housing due to the limit of the processing accuracy. That is, when a thin plate heat pipe is to be manufactured by drawing or extruding, the housing formed by drawing or extrusion has a problem in that the internal wick structure can not produce a capillary force due to limitations in drawing precision or extrusion processing It is not crumbled or distorted and normally can not be applied to the manufacture of a heat pipe.

In addition, as shown in the upper side of Fig. 1, there has been an attempt to roll the heat pipe 101 into a thin shape after manufacturing within the range of maintaining the processing accuracy by drawing or extrusion. In this case, however, A compression deviation occurs in the flat plate 111 at portions where the partitions 115 are located and portions where the partition 115 is located due to the buckling resistance of the partitions 115 of the housing 103, The heat pipe 101 manufactured by the housing 103 has a problem in that the heat resistance of the contact portion with the heat source is increased when the product is applied and the heat generating performance is remarkably deteriorated.

1, when the upper and lower protrusions 121 and 121 are rolled as shown in the lower side of FIG. 1, the upper and lower protrusions 121 and 121, The upper groove 123 and the lower groove 123 are separated from each other. Therefore, since the gap between the upper groove 123 and the lower groove 123 is sufficiently wide under the assumption that the sectional area of the housing 103 is constant, the working fluid boiling at the time of degassing can be lost in the form of a liquid lump, There is a problem that the production efficiency of the heat pipe is deteriorated because the amount of fluid loss of the working fluid may become large. 1, the transverse sectional area in the longitudinal direction of the housing 103 is reduced due to buckling, resulting in deterioration of the performance of the heat pipe 101. The upper protrusion 121 and the lower protrusion 121, The resistance against the flow of the working fluid is increased, and the heat radiation performance of the heat pipe is deteriorated.

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to solve the problems of the conventional thin type heat pipe as described above, and a thin heat pipe of a thin thickness which can not be formed by drawing or extrusion due to the limit of machining accuracy is processed The present invention has been made to provide a thin heat pipe which is thin enough to cope with the trend of thinning of electronic products and which does not deteriorate heat dissipation performance or production efficiency.

In order to accomplish the above object, the present invention provides a method of manufacturing a wick, comprising: a pair of flat plates arranged to face each other with wicks extending in the longitudinal direction thereof formed on respective inner circumferential surfaces thereof; A housing manufacturing step of manufacturing a plate-like housing having a thickness thinner than a length or width by a pair of side walls; A working fluid injecting step of injecting a working fluid into the housing manufactured in the housing manufacturing step; And a finishing step of compressing the injection port of the housing into which the working fluid is injected in the operating fluid injecting step to seal the housing, wherein the housing manufacturing step is a step of forming the housing at a thickness capable of plastic working by drawing or extrusion A semi-finished product forming step of molding the semi-finished product of the housing; And a housing shaping step of rolling the semi-finished product of the housing formed in the semi-finished product shaping step to form the housing, wherein the semi-finished housing product reduces the buckling resistance generated during the rolling process, There is provided a method of manufacturing a thin heat pipe in which the inner peripheral surface of the pair of side walls is inclined so that the flat plate can be formed as a flat surface as a whole.

The method may further include removing the foreign matter including the non-condensable gas included in the working fluid and the housing before or after the injecting the working fluid.

Also, the housing has a multi-channel structure in which the working space is divided into a plurality of channels by a plurality of partition walls arranged in the width direction, and the housing semi-finished product reduces the buckling resistance generated in the rolling process It is preferable that the partition wall is inclined so that the flat plate can be flattened as a whole after the rolling process.

Preferably, the inclination angle of the partition wall of the semi-finished product of the housing is in the range of 40 to 70 degrees with respect to the flat plate.

Preferably, the wicks are arranged to be offset from each other in the width direction on the inner circumferential surface of the flat plate so as to keep the widthwise cross-sectional area of the working space constant.

The wick may include a plurality of protrusions protruding from the inner circumferential surface of each flat plate at a predetermined distance in the width direction; And a plurality of grooves formed between the plurality of protrusions to form a moving path through which the working fluid in a liquid flows, wherein the protrusions or grooves of the one flat plate and the grooves of the other flat plate The grooves or protrusions are preferably formed to be engaged with each other when the housing is compressed.

According to the thin-wall heat pipe manufacturing method of the present invention, since the side wall member and / or the partition wall of the housing are formed to be inclined with respect to the flat plate member constituting the upper and lower surfaces of the housing, Wrinkles of the wave pattern due to the buckling resistance do not occur on the flat plate of the housing. Therefore, the heat pipe manufactured according to the present invention is thin and does not need to worry about performance deterioration due to poor contact with a heat source when the product is applied.

Therefore, the plate-shaped heat pipe can be manufactured to have a thin thickness which can not be expected by conventional drawing or extrusion processing, so that the heat pipe can be made ultra thin in accordance with recent trends.

In addition, while the housing is thin as described above, the wicks formed so as to face each other on the inner circumferential surface of the upper and lower flat plates of the housing are staggered, and the side walls and the partition walls are inclined. Therefore, even in the presence of the wick, The heat transfer performance of the heat pipe can be maintained normally and the transverse sectional area of the housing in the longitudinal direction is not reduced due to the buckling of the side wall member or the partition wall so that the heat capacity of the heat pipe can be greatly improved.

1 is a transverse front view showing a housing of a heat pipe formed by drawing or extrusion;
2 is a block diagram sequentially illustrating a method of manufacturing a thin heat pipe according to an embodiment of the present invention.
3 is a view for explaining a manufacturing step of the heat pipe housing shown in Fig. 2;
Fig. 4 is a view for explaining a step of manufacturing the heat pipe housing shown in Fig. 2 in another embodiment; Fig.
Fig. 5 is a view for explaining the housing molding step shown in Fig. 2; Fig.
Figs. 6 and 7 are transverse front views showing the housing on the way to be squeezed in the finishing step shown in Fig. 2; Fig.
FIG. 8 is a schematic view sequentially illustrating the working fluid injection step, the degassing step, and the finishing step shown in FIG. 2; FIG.
FIG. 9 is a graph comparing the heat transfer performance of the housing shown in the lower side of FIG. 1 and the housing rolled according to the present invention in which a conventional thin housing is rolled.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of manufacturing a thin heat pipe 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 manufacturing method of the present invention includes a housing manufacturing step S10, a working fluid injecting step S20, and a finishing step S30. In the degassing step S40, .

Here, the housing manufacturing step S10 is a step of manufacturing a thin housing 3 suitable for manufacturing a thin type heat pipe. The housing manufacturing step S10 is a step of manufacturing a thin type heat pipe, The housing 3 is manufactured in the form of a thin plate having a thickness t thinner than that of the housing 3 as shown in Fig. 2, and includes a semi-finished product forming step S11 and a housing forming step S12 as shown in Fig.

At this time, in the semi-finished product forming step S11, the thin housing 3 having a precise structure including the wicks 5 is formed as a minimum thickness t as possible by plastic working such as drawing or extrusion, As a preliminary step for producing a thin heat pipe 1 which can not be manufactured by drawing or compression due to a relatively precise structure, before the housing 3 is processed into a final shape by rolling, The plate-shaped semi-finished product 10 as shown on the upper side of FIG. 3 and FIG. 4 is formed by drawing or extrusion so that the shape of the wick 5 and the like can be kept to a minimum while having the minimum thickness t.

The housing semi-finished product 10 is a preliminarily molded product prepared for manufacturing the thin housing 3, but may be a thin plate having a thickness t smaller than the length l or the width w like the housing 3 A pair of flat plates 11 arranged so as to face each other as shown on the upper side of FIGS. 3 and 6 and a pair of flat plates 11 connected to both side ends of the flat plate 11, A rear wall for connecting the rear end of the flat plate 11 and a finishing end of the front side closed by pressing such as a pinch operation after injecting the working fluid F, And the flat plate 11 and the side wall body 13 together with the rear wall and the finishing end form a working space S to receive the working fluid F therein.

The flat plate 11 is a part of the heat pipe 1 that forms a heat transfer surface and has a length longer than the side wall 13 and the rear wall forming the thickness of the heat pipe 1 as shown in FIG. And / or the width is remarkably long, so that the heat pipe 1 is entirely in the form of a plate. The wick 5 protrudes in the longitudinal direction on each of the inner circumferential surfaces of the flat plate 11 facing each other. When the wick 5 is finished with the housing 3, the wick 5 is cooled , The condensed working fluid is returned to the evaporator. At this time, as shown in FIGS. 3 and 4, the wick 5 has not only the shape of a semicircle or a parallelogram in cross section of the projection, but also a triangular or semi- It can be changed into various forms. Meanwhile, stainless steel, copper, aluminum, nickel, or the like can be used as the material of the semi-finished product 10 in the case of a heat pipe for room temperature (use temperature range 230 to 500 K).

In addition, the semi-finished product 10 may have a single operation space S surrounded by the flat plate 11 and the like, but it is preferable that the semi-finished product 10 has a multi-channel structure as shown in FIGS. To this end, the semi-finished product housing 10 is divided into a plurality of channels 17 by a plurality of partition walls 15, each of which defines an operating space S, It is preferable to make each channel 17 have the same shape by dividing by a certain distance in the direction of the channel 17, but the width w of the channel 17 may be different.

Particularly, although the semi-finished product 10 according to the present invention is not shown, the inner peripheral surface of the sidewall 13 in the case of a single channel structure, or the channel 17 in the case of a multi-channel structure as shown in Figs. 3 and 4, A plurality of partition walls 15 partitioning the partition wall 15 are formed at an angle to the side walls 13 or the partition walls 15 when the housing semi-finished product 10 is rolled, as shown in FIG. 5, Greatly reducing the buckling resistance that occurs. Therefore, the flat plate 11 of the housing 3, which is thinned by the rolling process, is uniformly rolled as a whole to form a flat surface.

At this time, it is preferable that the inclination angle of the side wall member 13 or the partition wall 15 is within a range of 40 to 70 degrees with respect to the surface of the flat plate 11. [ This is an optimum range that does not disturb the flow of the working fluid while reducing the buckling resistance of the partition 15 or the like. When the inclination angle is less than 40 degrees, the angle between the partition 15 and the flat plate 11 is greatly reduced The flow resistance of the working fluid flowing in the housing 3 completed with the heat pipe 1 is greatly increased to result in lowering the heat transfer performance of the heat pipe 1 and conversely the inclination angle is more than 70 deg. , The effect of reducing the buckling resistance of the sidewall 13 or the partition 15 is reduced, and the waveform deforms in the flat plate 11 after rolling.

The housing molding step S12 is a step of rolling the semi-finished product 10 molded by drawing or extrusion in the semi-finished product molding step S11 into the housing 3 of the finished product as described above, For example, the thickness t of the semi-finished product 10 is gradually reduced by the rolling roll 20 continuously arranged in three stages as shown in Fig. 5 to form the thin housing 3.

3 and 4, the thinned housing 3 is formed into a thin plate having a length l and / or a width w which is significantly longer than the width w, like the housing semi-finished product 10, A pair of upper and lower flat plates 11, a pair of left and right side plates 13 connecting the left and right ends of the flat plate 11, and a rear wall connecting the rear ends of the flat plates, And a finishing end opened to the front face of the body, and these walls form an operating space S for receiving the working fluid F therein. 3 and 4, when the housing semi-finished product 10 is housed in the housing 3 as shown in Figs. 3 and 4, the sidewall 13 on both side ends of the housing 3 and the partition 15 partitioning the working space S, The thickness t, that is, the height is shortened, the width w, that is, the thickness is thickened, and the inclination angle becomes larger by buckling.

3 and 4, various types of wicks 5 are formed on the inner circumferential surface of the flat plate 11, and the upper and lower flat plates 11, The formed wicks 5 are preferably staggered with respect to each other in the width direction to maintain a constant flow cross sectional area of the flow formed in the working space S in the width direction. Otherwise, the flow resistance of the working fluid F greatly increases, resulting in deterioration of the heat transport ability of the heat pipe 1.

2 to 7, the wick 5 includes a plurality of protrusions 21 and grooves 23 formed between the protrusions 21, as described above. In this case, The plurality of protrusions 21 protrude from the inner circumferential surface of each of the upper and lower flat plates 11 of the housing 3 and are formed at a predetermined distance in the width direction and extend in the longitudinal direction of the housing 3, To connect the evaporation portion of the housing 3 and the condensing portion. 4, each of the projections 21 can be inclined in the same direction as the inner peripheral surface of the sidewall 13 or the inclined direction of the partition 15. In this case, the inclined sidewall 13 is inclined, The flow resistance of the working fluid through the wick 5 can be reduced in the same manner as the partition wall 15 or the partition wall 15. As described above, the groove 23 is also a moving passage through which the working fluid F condensed in the condensing portion is returned to the evaporator. As shown in the same manner as the protrusion 21, the groove 23 is elongated in the longitudinal direction of the housing 3 Thereby moving the working fluid of the condensing portion to the evaporating portion by the capillary force.

3 and 4, the wicks 5 according to the present invention are preferably arranged such that the respective positions formed on the upper and lower flat plates 11 are shifted from each other, The projections 21 and the grooves 23 corresponding to the upper and lower portions are engaged with each other as shown in FIGS. 6 and 7 in the process of being pressed by the pinch or the like, The gap g of the injection port 9 to be sealed by the compression is narrower than in the structure in which the gap g is not engaged so that the sealing of the injection port 9 is performed more quickly, F can be adjusted more precisely. That is, when the projections 21 and the grooves 23 are engaged with each other when the injection port 9 is pressed, the gap between the upper and lower grooves 23 is smaller than that of FIG. 1 in which the gap between the upper and lower grooves 23 is not engaged as shown in FIGS. 3 and 4 , The sealing time of the injection port 9 by the pinch compression is shorter than that in the case of FIG. 1, and considering the characteristic that a large amount of the working fluid F is instantaneously boiled and lost during the degassing, It is possible to more precisely control the injection amount of the working fluid F of the finished heat pipe 1 according to the amount of fluid loss, that is, the amount of fluid loss.

The working fluid injecting step S20 is a step of injecting a working fluid into the housing 3 formed through the upper housing manufacturing step S10. As shown in FIG. 8, (F) is injected into the housing (3) through the opening (9). At this time, the working fluid is a heat transfer medium which is housed in the housing 3 and rapidly transfers the heat applied from the heat source to the evaporator at one end of the housing 3 to the condenser at the other end to discharge the heat to the outside. And is received in a sealed state in the working space S shown in Figs. Accordingly, the working fluid F is heated and vaporized by the heat of the heat source adhering to the evaporator, cooled in the condenser, and recovered to the evaporator through the wick 5. At this time, as the working fluid, methanol, ethanol, ammonia, an ethene, a fluorocarbon compound, and water can be used. At this time, the amount of the working fluid F to be injected into the housing 3 is determined in consideration of the amount of fluid in the degassing step S30 and the amount of filling of the final product.

The finishing step S30 is a step of closing the injection port 9 of the housing 3 to finish the manufacturing of the heat pipe 1 and as shown in Figure 8, The inlet 9 of the housing 3 into which the resin F is injected is pressed by a pinch or the like to seal the housing 3, thereby completing the series of manufacturing processes of the heat pipe 1.

Therefore, the heat pipe 1 as shown in FIG. 3, which is manufactured through the above steps, as seen from the graph of FIG. 9, has a problem in that compared with the conventional heat pipe 101 shown in FIG. 1, The thermal resistance is significantly reduced since buckling deformation of the partition 15 and the side wall 13 is relatively small and therefore the reduction of the cross sectional area of the housing 3 after rolling is also relatively small. That is, when heat is to be discharged from a heat source at a specific temperature under the same condition, the heat pipe 1 having a larger flow cross-sectional area of the working fluid F can discharge heat at a higher rate than the heat pipe 101 .

The heat pipe can be used up to a range where the amount of heat released from the condensing portion and the amount of heat absorbed by the evaporating portion coincide with each other, that is, within a range where the temperature of the heat discharging furnace itself in the condensing portion does not rise, Assuming that the range in which the heat resistance is kept constant despite the increase in the heat load is the heat capacity and the sectional area of the housing 3,103 in the longitudinal direction is the same, The heat capacity of the heat pipe 1 is larger than the heat capacity of the heat pipe 101 and therefore the usable range of the heat pipe 1 according to the present invention A becomes wider than the allowable range B of the conventional heat pipe 1.

The degassing step S40 may be performed before or after injecting the working fluid F into the housing 3 in the working fluid injecting step S20, As shown in FIG. 8, in the step of injecting the working fluid (S20) according to the heating deaeration technique, the deaeration is performed in various steps such as vacuum deaeration or heating deaeration. The foreign substance can be removed by heating the housing 3 into which the working fluid is injected. 5, a heating means such as a heating bath 30 is used. In the housing 3, the lower portion of the housing 3 is filled with the working fluid F, And is heated by the hot water. When the housing 3 is heated by the heating bath 30 as described above, nitrogen, oxygen, water or nitrogen, which has been adsorbed on the wall surface of the housing 3 or dissolved in the working fluid F, And the vaporized foreign matter is simultaneously removed out of the housing 3 through the inlet 9 together with the working fluid of the vapor phase or the liquid phase.

1: heat pipe 3: housing
5: wick 9: inlet
10: Housing semi-finished product 11: Flat plate
13: side wall 15: partition wall
17: channel 20: rolling roll
21: projection 23: groove
30: bathtub F: working fluid
g: spacing l: length
t: Thickness w: Width
S: Working space

Claims (6)

A pair of flat plates 11 arranged in such a manner as to face each other while wicks 5 extending in the longitudinal direction are formed on respective inner circumferential surfaces thereof and a pair of flat plate members 11 connected to both side ends of the flat plate 11, (S10) of manufacturing a plate-like housing (3) having a thickness (t) thinner than the length (l) and the width (w) by means of a pair of side walls (13)
A working fluid injection step (S20) of injecting the working fluid (F) into the housing (3) manufactured in the housing manufacturing step (S10); And
And a finishing step (S30) of pressing the inlet (9) of the housing (3) into which the working fluid (F) is injected in the injection step (S20) to seal the housing (3)
The housing manufacturing step (S10)
A semi-finished product molding step (S11) of molding the semi-finished product (10) of the housing (3) to a thickness capable of plastic working by drawing or extrusion; And
And a housing molding step (S12) of molding the housing (3) by rolling the semi-finished product (10) molded in the semi-finished product molding step (S11)
The housing half product 10 is formed by reducing the buckling resistance generated during the rolling process so that the inner peripheral surface of the pair of side walls 13 is inclined so that the flat plate 11 can be flattened as a whole after the rolling process Wherein the heat pipe has a thickness of about 10 mm. The method according to claim 1,
And a deaeration step (S40) of removing the foreign substance including the non-condensable gas contained in the working fluid (F) and the housing (3) before or after the operating fluid injecting step (S20) A method of manufacturing a heat pipe. The method according to claim 1 or 2,
The housing (3) has a multi-channel structure in which the working space (S) is divided into a plurality of sections by a plurality of partition walls (15) arranged in the width direction to form a plurality of channels (17)
Characterized in that the housing half (10) is inclined so that the flat plate (11) can have a flat surface as a whole after the rolling by reducing the buckling resistance generated during the rolling process. A method of manufacturing a heat pipe. The method of claim 3,
Wherein the inclined angle of the partition wall (15) of the semi-finished product (10) is in a range of 40 to 70 degrees with respect to the flat plate (11). The method of claim 3,
Wherein the wicks (5) are arranged to be shifted from each other in the width direction on the inner circumferential surface of each of the flat plates (11) so as to keep the flow cross sectional area in the width direction of the working space (S) constant. . The method of claim 5,
The wick (5)
A plurality of protrusions (21) protruding from the inner circumferential surface of each flat plate (11) at a predetermined distance in the width direction; And
And a plurality of grooves (23) formed between the plurality of projections (21) to form a moving path through which the working fluid (F) in a liquid moves,
The protrusions 21 or the grooves 23 and the grooves 23 or the protrusions 21 of the flat plate 11 on the other side of the flat plate 11 on the one side press the housing 3 Wherein the first and second heat pipes are formed to be engaged with each other.

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