JP2743345B2 - Heat pipe and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has a high heat transport efficiency,
The present invention relates to a heat pipe suitable for cooling a small heating element having a flat portion, and a method for manufacturing the heat pipe.

[0002]

2. Description of the Related Art For example, in the field of personal use computers (hereinafter referred to as personal computers), so-called portable personal computers of the notebook type and the sub-notebook type have been remarkably popularized. Since the main purpose of this type of personal computer is portability, a reduction in size and weight is strongly desired. Therefore, naturally, the space occupied by the cooling device in the internal space of the personal computer is extremely limited. On the other hand, the output of the arithmetic processing unit has been increasing year by year with the increase in the number of functions and the processing speed, and therefore, the amount of heat generated by the arithmetic processing unit has also increased. Therefore, conventionally, a heat pipe having excellent heat transport ability has been used as a cooling device.

FIG. 32 shows an example of a heat pipe used for cooling in a conventional personal computer. The heat pipe 1 is a so-called plate type heat pipe, container is formed in a rectangular cross section, the lower surface is a heated portion 1a in FIG its container, and the upper surface is a heat radiating portion 1b . A large number of radiating fins 1c are provided outside the radiating portion 1b. After being evacuated, only a predetermined amount of condensable working fluid 3 such as water is sealed in the container.

[0004] The heat pipe 1 having the above-described structure is electrically connected to a predetermined portion of a circuit formed on the printed circuit board 4 and attached thereto.
The heating unit 1a (lower surface) is attached to the upper surface of a CPU 2 in close contact.

In the heat pipe 1, when the CPU 2 generates heat when the circuit is energized and the heating unit 1a is heated by the heat, the enclosed working fluid 3 is heated and boiled to generate steam. Then, the vapor of the working fluid 3 moves upward and condenses in the low-temperature radiator 1b. Further, the heat carried in the state of the latent heat of vaporization of the working fluid 3 is radiated from the radiation fins 1c provided outside the radiation part 1b.

Therefore, the radiation fins 1c can be efficiently dissipated by allowing the radiation fins 1c to face a flow path of cooling air by a cooling fan (not shown) in the housing of the personal computer. As described above, by using the heat pipe 1 for cooling the CPU 2, a large amount of heat can be transported in the state of latent heat of evaporation, so that the CPU 2 can be effectively cooled. As a result, it is possible to prevent the personal computer from becoming inoperable or deteriorating in function due to overheating of the CPU 2.

[0007]

According to the above-mentioned conventional heat pipe 1, in addition to its extremely high thermal conductivity, it comes into direct contact with the CPU 2, which is a heat source, over a wide area. The cooling efficiency of the CPU 2 can be improved. However, since the container is a hollow body having a rectangular cross section, the area of contact with the CPU 2 can be increased, but the area of the heat radiation portion 1b is relatively small. That is, since the working fluid 3 is a liquid in the heating unit 1a and the heat source is the CPU 2, the heating fluid 1
It suffices that a has an area approximately equal to the upper surface of the CPU 2, but the working fluid 3 is vapor in the heat radiating portion 1b.
Since the volume is extremely increased, in the conventional heat pipe 1 in which the heat radiating portion 1b has the same area as the heating portion 1a, the heat radiating portion 1b to which the vapor of the working fluid 3 directly contacts is limited, and the heat radiation amount is reduced. Thus, there is a disadvantage that the substantial cooling capacity is limited.

The present invention has been made in view of the above circumstances, and has as its object to provide a heat pipe capable of efficiently transporting heat from a local heat source and a method of manufacturing the heat pipe. .

As a means for solving the above problems, the present invention heats and boiles the working fluid by the heat input to the heating section side of the container, and the generated steam moves to the heat radiating section and is condensed. In the heat pipe for transporting writing heat to the heat radiating portion, the container includes a flat heating portion, a heat radiating portion spaced above the heating portion and having a larger area than the heating portion, and a heating portion and a heat radiating portion. Are formed in a hollow flat shape by a side wall portion connecting the respective peripheral portions to each other over the entire circumference, and further, an inner surface of the heating portion.
In addition to the projections that induce nucleate boiling,
On the inner surface of the heat radiating part, there is a convex part that promotes dripping of the working fluid.
It is characterized by being provided .

[0010]

[0011]

Further, according to the manufacturing method of the present invention, the plastically deformable pipe material is crushed in the radial direction to form a hollow flat shape, and both open ends of the flat shape pipe material are sealed. A step of forming a working fluid inlet at one end to form a container, and condensing the inside of the container in a vacuum degassed amount smaller than the capacity of the container.
A step of heat pipe of encapsulating a sex flow body as the working fluid, the unfinished containers the heat pipe of, while accommodated in the cavity having a predetermined internal shape,
Increasing the internal pressure by heating the container, pressurized in all directions containers from the inside, and a step of the entire area of its outer wall surface is pressed against the inner wall surface of the cavity for molding the shape to follow the cavity shape It is characterized by having.

[0013]

According to the heat pipe of the present invention, the shape of the container in which the working fluid is sealed is defined by a flat heating section, a radiating section spaced above the heating section and having a larger area than the heating section. Since the peripheral portions of the heat dissipating portion and the heat dissipating portion are formed to have a hollow flat shape by the side wall portions connected to each other over the entire circumference, the area of the heat dissipating portion is larger than the area of the heating portion. Accordingly, a large amount of steam is brought into contact with the heat radiating portion to increase the amount of heat radiated and condensed of the working fluid vapor, thereby making it possible to form a heat pipe having a higher heat transport capability. In addition, the heat according to claim 1
The top pipe has a structure with a protrusion on the inner surface of the heating section.
Nucleate boiling is induced, which promotes the evaporation of the working fluid
The heat transfer from the heating section to the working fluid improves
Therefore, the heat transfer efficiency as a heat pipe becomes higher.
Further, in the heat pipe according to claim 1, the heat radiating section
Because of the structure with a convex part on the inner surface of the
The dripping of the condensed working fluid is promoted, and the liquid film
Reduces the area of contact with steam and
Compression efficiency is increased, and the working fluid is encouraged to return to the heating section.
Heat transfer capacity as a heat pipe
improves.

[0014]

[0015]

According to the manufacturing method of the second aspect, since the shape of the heat radiating portion expanded from the heating portion is formed using the pressure of the working fluid after the heat pipe is formed,
A heat pipe with an enlarged heat radiating section can be efficiently manufactured with a small number of steps.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the heat pipe of the present invention is applied to a heat pipe for cooling a CPU of a personal computer will be described below with reference to FIGS.

FIG. 1 to FIG. 5 show an embodiment of the present invention. As shown in FIG. 1 to FIG. It has a shape like a truncated pyramid. More specifically, the container 12 has a substantially square heating section 12a having a side of about 30 mm and a substantially square heating section 12a having a side of about 60 mm, and has an area about four times that of the heating section 12a.
Radiator 12 formed in parallel above and separated by about 5 mm
b and four inclined side wall portions 12c connecting the four sides of the heat radiating portion 12b and the four sides of the heating portion 12a, respectively. A predetermined amount of a condensable fluid such as pure water is sealed in the container 12.

As shown in FIGS. 4 and 5, the heat pipe 11 having the above-described structure is disposed on the upper surface of the CPU 16 with the lower heating section 12a having a small area in close contact therewith. The CPU 16 includes a printed wiring (not shown) formed on a circuit board 15 in a personal computer.
Is attached at a predetermined position. A heat sink 14 is integrally joined to the heat radiating portion 12b on the upper side of the heat pipe 11 so that heat can be transmitted. That is, in the heat sink 14, a large number of radiating fins 14a made of an aluminum plate having a thickness of about 0.6 mm are arranged in parallel at a narrow interval (for example, about 1.0 mm pitch), and the lower ends of the radiating fins 14a are It is integrated with a base plate 14b made of an aluminum plate by welding or the like, and is attached to the heating unit 12b by the base plate 14b.

The heat pipe 11 to which the heat sink 14 is integrally attached has its outer peripheral portion reinforced by a holder 17 at a portion connected to the heat sink 14 and is fastened and supported on a circuit board 15. Reference numeral 18 in FIGS. 4 and 5 indicates a rectifying plate provided in three stages so as to divide the heat sink 14 into a plurality of upper and lower parts, and the wind flowing in the gap between the heat radiation fins 14a flows in the horizontal direction. I'm guiding you.

Next, the operation of this embodiment shown in FIG. 4 will be described. When the CPU 16 generates heat by being energized, the heat heats the lower heating portion 12 a of the heat pipe 11 which is in contact with the CPU 16. When the heating unit 12a is heated, the working fluid 13 sealed inside is heated. The working fluid 13 that has been heated and boiled in this way becomes a vapor, flows toward the low-temperature radiating section 12b, and is deprived of heat by the radiating section 12b and condensed. That is,
The vapor of the working fluid 13 transports the heat generated by the CPU 16 as latent heat of evaporation, and the heat is released when the heat is condensed in the radiator 12b.

The released heat is transmitted from the heat radiating section 12b to each of the heat radiating fins 14a of the heat sink 14.
The heat is dissipated from each of the heat radiation fins 14a to the space in the housing of the personal computer. Therefore, cooling can be efficiently performed by allowing the cooling fan (not shown) to face the cooling air flow path.

On the other hand, part of the working fluid 13 which is condensed and adheres to the wall surface of the heat radiating portion 12a drops on the wall surface of the heating portion 12a as it is, and a large amount of other working fluid travels along each inclined side wall portion 12c. Reflux to the heating section 12a. Since the inclined side wall portion 12c connects all the four sides of the heat radiating portion 12b and the four sides of the heating portion 12a as described above,
The working fluid 13 recirculates on the upper surface of the heating unit 12a so as to concentrate from almost all directions. Therefore, the evaporation / condensation cycle of the working fluid 13 is performed smoothly.

Particularly, in the heat pipe 11, since the area of the heat radiating portion 12b is formed to be four times as large as the area of the heating portion 12a, the vapor of the working fluid moved to the heat radiating portion 12b has a low temperature. The rate of contact with the inner surface of the heat radiating portion 12b is four times higher than that of the conventional cooling heat pipe, and therefore, a large amount of steam can be condensed. Also, excellent cooling performance can be exhibited, and overheating of the CPU 16 can be reliably prevented.

In the above embodiment, the heating unit 12
On the inner surface of a, a convex portion for inducing nucleate boiling is provided.
On the other hand, the working fluid is
Is provided to promote the dropping of the liquid.

More specifically, as shown in FIG. 6, for example, as shown in FIG. By forming V-shaped grooves at narrow intervals in two directions perpendicular to each other, a large number of quadrangular pyramid-shaped cusp projections 23 are formed on the inner surface of the. This many point projections 2
Reference numeral 3 shows an early transition from the non-boiling region to the nucleate boiling region when the heating section 22a is heated and the heat is transferred to the working fluid. In other words, it prevents the transition to the film boiling region when the working fluid on the surface of the heating section 22a is reduced, and acts to maintain the nucleate boiling with high heat transfer efficiency.

A plurality of short ribs 24 are formed on the inner surface of the heat radiating portion 22b having a large upper area and parallel to each other so as to be sufficiently separated so as not to cause a capillary phenomenon. These ribs 24 adhere to the ribs 24 due to the surface tension when the vapor that has been deprived of heat by contacting the heat radiating portion 22b condenses and condenses on the inner surface of the heat radiating portion 22b. As a result, the particles are easily dropped by gravity. Therefore, the heat dissipating portion 22b that contacts and condenses the steam of the working fluid
Is prevented from being reduced by being covered with condensed working fluid.

Further 7, protrusion Ru to induce the nuclear boiling
When the convex portion Ru promotes the dropping of the working fluid is indicative of the longitudinal section of the different separate containers, respectively. In the metal container 25, a large number of small metal spheres 26 made of copper or the like are sintered on the inner surface of the heating unit 25a as an uneven shape for generating nucleate boiling. The large number of metal spheres 26 have the same function as the spike 23 in the example shown in FIG. That is, when boiling heat is transferred from the heating unit 25a to the working fluid, the transition from the non-boiling region to the nucleate boiling region is made early, and the transition to the film boiling region when the working fluid on the surface of the heating unit 25a is reduced. And acts to maintain nucleate boiling with high heat transfer efficiency.

On the inner surface of the heat radiating portion 25b, short ribs 27 are formed in a lattice shape.
Numeral 7 has the same action as the rib 24 in the example shown in FIG. 6, and makes it easy to drop the droplets of the working fluid condensed on the inner surface of the heat radiating portion 22b.

Further, in the above embodiment, the case where the shape of the container 12 of the heat pipe 11 is a flat quadrangular pyramid (a trapezoidal cross section as shown in FIGS. 3, 6 and 7) has been described. As shown in a container 27 shown in FIG. 7, a small square heating section 27a and a large area square heat radiating section 27b are connected to a vertical side wall 27c continuous to each side of the heat radiating section 27b, a lower side of the vertical side wall 27c, It can be formed in a pentagonal cross section composed of the inclined side wall 27d connecting each side of the portion 27a.

Further, as in the container 28 shown in FIG. 9, the lower heating section 28a can be formed at a position deviated from the center of the lower portion of the upper heat radiating section 28b. When the space above the installation location of the CPU 16 is narrow and a space exists only in a specific direction, the cooling heat pipe is formed by expanding the heat radiating portion 28b in the direction of the space. It can be mounted.

Further, in the above embodiment, as shown in FIG. 2, the size and shape of the heating portion 12a of the heat pipe 11 are made substantially the same shape and size as the upper surface of the CPU 16, and the radiating portion 12b is Heating section 12a
The shape and size were enlarged while maintaining the similar shape to
As shown in FIG. 10, the heat radiating portion 31b may be formed in a circular shape with respect to the square heating portion 31a. In this case, the shape of the heat sink 32 attached to the outside of the heat radiating portion 31b is adjusted to the shape of the circular heat radiating portion 31b.
The length “a” is formed such that the center is longer in the direction in which the wind flows and the left and right sides are gradually shortened.

As shown in FIG. 11, the heating unit 33a
The heat sink 34 and the heat radiating portion 33b can be formed in circular truncated cones having different diameters, and the heat sink 34 also has the length of each heat radiating fin 34a with respect to the direction in which the wind flows, as in the case shown in FIG. It is formed so that the center is lengthened and gradually shortened on both left and right sides.

The method of attaching the heat sink 14 to the heat pipe 11 will now be described. As shown in FIG.
A base plate 14b made of an aluminum plate to which a number of heat radiation fins 14a are attached at a predetermined pitch is placed so as to be in close contact with the upper surface of the heat radiation part 12b of the heat pipe 11.
In this state, the edges of at least two opposing sides of the base plate 14b are bent downward, respectively, and further, are caulked so as to sandwich the edge of the heat radiating portion 12b of the heat pipe 11. Therefore, the heat radiating portion 1 of the heat pipe 11
The heat carried to 2b is efficiently transmitted to each radiating fin 14a via the base plate 14b.

Another method of attaching the heat sink will be described. For example, as shown in FIG.
Mounting grooves 43a are formed at a predetermined pitch on the upper surface of the heat radiating portion 43 of the heat pipe 42 so as to fit the respective lower sides of the large number of heat radiating fins 41a made of a thin aluminum plate that constitutes 1. Then, after fitting the lower part of the radiation fin 41a into each of the mounting grooves 43a, press the flat portion between the mounting grooves 43a on the upper surface of the heat radiating portion 43 to reduce the groove width of the mounting groove 43a and caulking. Alternatively, the heat radiation fins 41a are pressed downward and buckled to increase the thickness in the mounting groove 43a, thereby mounting. Therefore, the heat transferred to the heat radiating portion 43 of the heat pipe 42 is directly transmitted to each of the heat radiating fins 41a.

FIG. 14 shows another mounting method of the heat sink. The heat sink 46 is formed by welding a large number of radiating fins 46a at a predetermined pitch on a base plate 46b made of an aluminum plate, and a lower surface of the base plate 46b is connected to an upper surface of a radiating portion 47b of the heat pipe 47 by a thermal joint (metal powder). (Adhesive containing) 48, and is adhered and attached.

Therefore, the heat radiating portion 4 of the heat pipe 47
7b is attached to the base plate 4 by the thermal joint 48 so as to be in close contact therewith.
The heat is efficiently transmitted to each radiating fin 41a via 6b.

In the above example, the case where the flat radiating fins 14a, 41a and 46a made of an aluminum plate are used has been described. It is sufficient if the heat sink 48 is made of a metal having an excellent property. As shown in FIG.

The shape of the radiation fin is shown in FIG.
As shown in a heat sink 49 shown in FIG.
If a is arranged at a predetermined pitch and used, excellent heat radiation performance can be obtained by the vortex effect of air (wind) flowing through the gap between the corrugated plates 49a.

As shown in FIG. 17, if a large number of radiating fins 50 which are short in the direction of flow of the wind are provided in a staggered manner in parallel with the flow of the wind, the wind directly collides with the front edge of each fin 50. Due to the cooling effect, that is, the leading edge effect, excellent heat dissipation performance can be obtained.

In the above embodiment, the heat sink 14 is provided with three horizontal rectifying plates 18 so that
The heat radiation effect is enhanced by preventing the air (wind) flowing between a and a part from flowing out of the heat sink 14 from the middle, but instead of the rectifying plate 18, as shown in FIG. A flap-shaped guide plate 52 for guiding the inflowing air downward may be provided in three stages on the air inflow side of the gap serving as the air passage. In this way, the heat radiation efficiency can be increased by flowing air to the lower part of each of the heat radiation fins 51 whose temperature is increased by being connected to the heat pipe 11 serving as a heat source. Moreover, by flowing air diagonally downward,
The laminar flow of the air flowing along the upper surface of the heat radiating portion 11b of the heat pipe 11 can be prevented from being separated, and the heat radiation efficiency can be increased by increasing the flow amount of the air.

Also, instead of the guide plate 52 on the flap shown in FIG.
The same effect as the guide plate 52 can be obtained even if a number of jammer plates 53 are provided in the gap between them with their downstream sides directed obliquely downward. Further, as shown in FIG. 20, instead of the jammer plate 53, a triangular plate 54 in which a thin plate is formed into a right-angled triangle is attached to the gap between the heat radiation fins 51 so that the hypotenuse of the triangular plate is on the lower side. Similar effects can be obtained.

In the above description, an example is shown in which the heat pipe 11 of the present invention is used for cooling the CPU 16 of a personal computer. However, the present invention is not limited to the above embodiment.

Here, a method of manufacturing the heat pipe 11 having the above configuration will be described. Note that the same reference numerals are given to the above-described members, and detailed description thereof is omitted. First, as a material of the container 12, a metal pipe having a circular cross section, for example, a copper pipe 55 cut into a predetermined size in advance is prepared. As shown in FIG. 21, a plurality of linear grooves 80 extending in the axial direction and a plurality of annular grooves 81 extending in the circumferential direction are formed on the inner wall surface of the pipe 55. These grooves 80 and 81 are provided as convex portions for inducing nucleate boiling and convex portions for promoting the dripping of the working fluid, respectively.

Next, the grooved pipe 55 is processed into a hollow flat shape. FIG. 22 shows a schematic configuration of a press machine 56 as a processing facility, and a die (molding die) of the press machine has a recess having a depth substantially equal to the thickness of a flat shape to be formed. Lower mold 57 and its lower mold 5
And a punch 58 that is lowered so as to close the opening 7. In other words, the bottom surface of the concave portion of the lower mold 57 and the lower surface of the punch 58 are molding surfaces which press the pipe 55 to press it, and both surfaces are flat surfaces parallel to each other.

In order to process the pipe 55 into a hollow flat shape by the press machine 56, first, the pipe 55 is inserted between the lower mold 57 and the punch 58. And punch 58
Is lowered, the lower surface of the punch 58 comes into contact with the upper surface of the pipe 55, and the punch 55 is further lowered from this state, whereby the pipe 55 is deformed from an elliptical cross-sectional shape to an elliptical shape. In this way, the punch 58 is lowered to the lower limit position and formed into the shape shown in FIG.

Then, the flat crushed pipe 5
5 is degreased and washed. As the cleaning means, conventionally known means such as cleaning using an appropriate solvent or ultrasonic cleaning can be adopted.

Next, one open end 64 of the pipe 55 crushed in a flat shape is closed. Here, as an example, the edge of the pipe 55 is crushed in the thickness direction over the entire region in the width W direction, and the width of the crushed portion in the length L direction is several mm.
The width is as small as possible (see FIG. 24A). Then, the edges of the inner peripheral surface of the pipe 55 are brought into close contact with each other substantially at the center in the thickness direction. In the crushing process, a conventionally known press machine, jig, or the like can be used.

In the same manner as described above, the edge of the inner peripheral surface of the pipe 55 is brought into close contact with the other open end 65 of the pipe 55 at substantially the center in the thickness direction.
At this end, an opening 59 for mounting the injection nozzle 61 communicating with the internal space is formed substantially at the center in the width W direction.
(See FIG. 24B). As a means for forming the opening 59 as an inlet for the working fluid (not shown), for example, a press machine having a depression portion corresponding to the opening 59 in advance on the molding surfaces of the upper die and the lower die is used. And the like.

Next, both open ends 64,
The joints 65 are sealed by welding or the like. At this time, an end of the injection nozzle 61 is inserted into the end where the opening 59 is formed, and is simultaneously fixed by welding or brazing (see FIG. 25). Here, as the injection nozzle 61, a small-diameter pipe having the same material as the pipe 55 and having a circular cross section is employed. Further, as another method of closing the open ends 64 and 65, a method of welding an oval end plate having substantially the same cross-sectional shape as the pipe 55 is used.

Next, the pipe 55 is made into a heat pipe. That is, pure water as a working fluid is injected into the pipe 55 through the injection nozzle 61 slightly more than a specified amount. This is because the non-condensable gas is expelled from the inside of the pipe 55 in the next step. As an example of this heating drive-out step, as shown in FIG. 26, the pipe 55 is set so that the end where the injection nozzle 61 is provided faces upward.
Is placed in a silicone oil bath 62 and heated to about 120 ° C. Then , non-condensable gas such as air in the pipe 55
Together with non-condensable gas dissolved in the working fluid
Released from the open end of the note inlet nozzle 61 by the working fluid vapor to the outside of the pipe 55. That is, first, the pipe 55
The amount obtained by subtracting the amount expelled as steam from the total amount of the working fluid enclosed in the inside is defined as the substantial amount of the working fluid.

After expelling a predetermined amount of steam, the tip of the injection nozzle 61 is temporarily sealed by caulking or the like. Therefore, the pipe 55 itself becomes the container 12 of the heat pipe 11 which has been sufficiently degassed. In addition, in this heating drive-out step, a method may be adopted in which the pressure inside the pipe 55 is increased in a state where the injection nozzle 61 has been temporarily tightened in advance, and then the temporarily tightened portion is opened to flush the working fluid. Note that, in this embodiment, as an example of a method of degassing and sealing a working fluid into the inside of the container 12, a heating purge method is exemplified. However, a vacuum pump method, a gas liquefaction method, or the like may be employed instead.

Next, the heat pipe 11 is seasoned. As is well known, this step is to improve the reliability of the heat pipe 11 in general, such as finding a fine pinhole or improving the wettability between the inner wall surface of the pipe 55 (container 12) and the working fluid. As shown in FIG. 27, for example, the heat pipe 11 is housed in a heating furnace such as a batch furnace or a tubular furnace 63 and is continuously heated at about 100 ° C. for a certain time. After the above steps are completed, the temporary sealing of the injection nozzle 61 is cut off to open it, and the working fluid inside is discarded. If there is unnecessary matter such as scale inside the container 12, it is taken out of the container 12 together with the working fluid at that time.
5 functions as a second washing step.

Next, a slightly larger amount of pure water than the specified filling amount is newly injected into the empty pipe 55 (container 12) . That is, the amount of pure water is
Less than the capacity of Their were again, implemented expelling heating in the same manner as described above, after the non-condensable gas is discharged from the pipe 55 inside which dissolved in the working fluid, the injection nozzle 61 end of the base end or the pipe 55 (See FIG. 28) . As a result,
Water is enclosed in the container 12. Na us, upon sealing, for example, once in a crimped state, if crimping cutting that part jig having a moderate rounded tip, air tightness can be more reliably secured. Also, welding is performed as necessary.

Next, the container 12 is formed.
FIGS. 29 to 31 are views showing a molding process of the container 12, and the molding die 70 shown here is composed of an upper die 71 and a lower die 72. The lower mold 72 has a bottom surface 72 a for shaping the heating portion 12 a of the heat pipe 11, and an inclined side wall portion 1 of the heat pipe 11 on four sides of the bottom surface 72 a.
An inclined surface 72b (only two surfaces are shown) extending upward to form 2c is provided. A plurality of heaters 73 are built in the lower mold 72 so as to approach the bottom surface 72a and the inclined surface 72b.
Can be independently temperature-controlled.

On the other hand, the upper die 71 is provided with an upper surface 71a for shaping the heat radiation portion 12b of the heat pipe 11.
That is, the upper mold 71 closes the upper opening of the lower mold 72, so that a cavity 74 having a substantially truncated pyramid shape is formed in the molding mold 70.

The container 12 is formed by the molding die 70 described above.
In order to form the heat pipe, the flat heat pipe 11 is accommodated in the cavity 74 of the molding die 70. Then, in this state, each heater 73 is operated, and 150 to 2
The lower mold 72 is continuously heated at a temperature of about 00 ° C. for a predetermined time. The heat of each heater 73 transmitted to the lower mold 72 is transmitted to the heat pipe 11, and the working fluid evaporates inside the container 12.

Here, since the heat input to the heat pipe 11 is not limited to the narrow range of the container 12 and is continued for a predetermined time, the evaporation of the working fluid in the container 12 is active. That is, the heat pipe 11 itself is maintained at a high internal pressure.
Therefore, the container 12 gradually starts plastic deformation from the inside toward all directions. In other words, the container 12 starts to expand over the entire area, but since the periphery of the heat pipe 11 is regulated by the upper mold 71 and the lower mold 72 as described above, the container 12 continues to expand,
The outer wall surface has a bottom surface 72a, a slope 72b, and an upper surface 71a.
Contact When the expansion of the container 12 further proceeds from this state, the outer wall surface of the container 12 is pressed against the bottom surface 72a and the inclined surface 72b, and finally the cavity 74
The heat pipe container is formed into a substantially truncated pyramid shape that follows the shape of the heat pipe . That is, the entire outer wall surface of the container 12
The region is pressed against the inner wall surface of the cavity 74.

Then, by gradually cooling the heat pipe 11, the container 12 is sufficiently annealed,
The surface is in a good condition without wrinkles or cracks. This molding step may be repeated several times.

Next, the heat pipe 11 is sent to a thermal characteristic inspection step (not shown) to inspect the heat transport amount, the uniform temperature, and the like. Then, for the heat pipe 11 that has passed the inspection standard, the outer surface of the container 12 is coated with, for example, nickel, and the heat radiation fins 14a manufactured in a separate process in advance are attached to the upper surface side of the container 12 in FIG. In addition, these attachment means are as described above. Next, although not specifically shown, the radiation fins 14a
Is sent to a final inspection step, and the appearance, dimensions, weight, heat transfer characteristics, and the like are inspected to complete the step.

[0061]

As described above, according to the first aspect of the present invention, the container comprises a flat heating section, a heat radiating section spaced above the heating section and having a larger area than the heating section. and the respective peripheral portions of the heat radiating portion over the entire circumference is formed in a hollow flat shape by a side wall portion for connecting together, further
On the inner surface of the heating section, a projection for inducing nucleate boiling is provided.
And at the same time, dripping of the working fluid
Since the convex portion for promoting the heat pipe is provided , the heat transport ability can be greatly improved as compared with the conventional heat pipe.

[0062]

[0063]

Further, the production method of the present invention comprises the steps of sealing both open ends of a pipe material crushed into a hollow flat shape and forming an inlet at one end, and reducing the volume of the container to less than the capacity of the container.
A step of heat Topaipu of encapsulating a free amount of condensable stream, pressurized from the inside in all directions to heat the pipe, with an internal shape matching the entire area of the outer wall surface to the finished shape of the heat pipe Since the method comprises a step of pressing the inner wall surface of the cavity and pressing it, a heat pipe excellent in heat transport ability can be efficiently manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a heat pipe of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a front view showing a state of being attached to a CPU.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a schematic sectional view showing an example of a container having irregularities on the inner surface.

FIG. 7 is a schematic sectional view showing another example of a container having irregularities on the inner surface.

FIG. 8 is a schematic sectional view showing an example of a container having a different shape.

FIG. 9 is a schematic sectional view showing another example of a container having a different shape.

FIG. 10 is a plan view showing a heat pipe having a circular heat radiating portion and a heat sink attached to the heat pipe.

FIG. 11 is a plan view showing another example of a heat pipe having a circular heat radiating portion.

FIG. 12 is a front view showing a state where a heat sink is attached to a heat pipe.

FIG. 13 is a front view showing another example of the state of attachment of the heat sink to the heat pipe.

FIG. 14 is a front view showing another example of the state of attachment of the heat sink to the heat pipe.

FIG. 15 is a perspective view showing a heat sink having a large number of heat radiation pins.

FIG. 16 is a plan view schematically showing a heat sink provided with wave-shaped heat radiation fins.

FIG. 17 is a plan view schematically showing a heat sink having slit fins arranged in a staggered manner.

FIG. 18 is a side view of a radiation fin to which a flap-shaped guide plate is attached.

FIG. 19 is a side view of a radiation fin to which a number of jammer plates are attached.

FIG. 20 is a side view of a radiation fin provided with a guide made of a right-angled triangular thin plate.

FIG. 21 is a perspective view showing a pipe in which a groove is formed on an inner surface.

FIG. 22 is a schematic diagram showing a mold and a pipe being crushed.

FIG. 23 is a perspective view showing a pipe crushed into a hollow flat shape.

FIG. 24 is a schematic view showing a pipe in a state where an open end is crushed.

FIG. 25 is a schematic view showing a pipe to which an injection nozzle is attached.

FIG. 26 is a schematic view showing a heating drive-out step.

FIG. 27 is a schematic view showing a seasoning step.

FIG. 28 is a schematic view showing a step of completely sealing an injection nozzle.

FIG. 29 is a schematic view showing a container forming step.

30 is a sectional view taken along line AA of FIG. 29.

FIG. 31 is a schematic diagram showing a state where a container of a heat pipe is expanded.

FIG. 32 is a diagram showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Heat pipe, 12 ... Container, 12a ... Heating part, 12b ... Heat radiating part, 12c ... Inclined side wall part, 1
3 ... working fluid, 22 ... container, 22a ... heating unit,
22b: heat dissipating part, 23: pointed protrusion, 24: rib,
25: Container, 25a: Heating part, 25b: Heat radiating part, 26: Metal sphere, 27: Grid-shaped rib, 27
... Container, 27a ... Heating part, 27b ... Heat radiation part,
28: container, 28a: heating unit, 28b: heat radiation unit, 31a: heating unit, 31b: heat radiation unit, 41: heat pipe, 43: heat radiation unit, 55: pipe, 59
... opening, 64 ... opening end, 65 ... opening end, 74 ...
cavity.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Saito 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Jin Hasegawa 5-1-1, Kiba, Koto-ku, Tokyo Fujikura Co., Ltd. (56) References JP-A-7-198280 (JP, A) JP-A-2-129297 (JP, U) JP-A-51-90181 (JP, U)

Claims (2)

(57) [Claims] 1. A heat pipe for heating and boiling a working fluid by heat input to a heating section side of a container, and transporting the heat input to the heat radiating section by transferring generated steam to a heat radiating section and condensing the working fluid. In the above, the container is a flat heating section, a heat radiating section spaced above the heating section and having a larger area than the heating section, and a peripheral portion of each of the heating section and the heat radiating section, It is formed in a hollow flat shape by the connecting side wall ,
On the inner surface of the heating section, a projection for inducing nucleate boiling is provided.
And at the same time, dripping of the working fluid
A heat pipe comprising a convex portion for promoting the heat pipe. 2. A step of crushing a plastically deformable pipe material in a radial direction to form a hollow flat shape, sealing both open ends of the flat pipe material, and one end of the flat shape. A step of forming a working fluid injection port into a container, and the inside of the container being evacuated to a vacuum .
A step of heat pipe of encapsulating a condensable flow body an amount smaller than the capacity as the working fluid, the unfinished containers the heat pipe of, while accommodated in the cavity having a predetermined internal shape , The container is heated to increase the internal pressure, the container is pressurized in all directions from the inside,
Method of manufacturing a heat pipe, characterized in that the entire surface by pressure contact with the inner wall surface of the cavity and a step of forming a shape to follow the cavity shape.