US20100251547A1

US20100251547A1 - Method of manufacturing a heat transport device, heat transport device, electronic apparatus, and caulking pin

Info

Publication number: US20100251547A1
Application number: US12/731,355
Authority: US
Inventors: Takashi Yajima; Kazuo Goto; Keitaro Yamashita; Kazuya Sakamoto
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2009-04-07
Filing date: 2010-03-25
Publication date: 2010-10-07
Also published as: JP2010243077A; CN101858702A

Abstract

A method of manufacturing a heat transport device includes injecting a working fluid that transports heat by a phase change into a casing through an injection opening of the casing under reduced pressure, sealing an injection path by caulking under the reduced pressure, the injection path being provided in the casing into which the working fluid is injected and causing the injection opening and an action area in which the phase change of the working fluid occurs to communicate with each other, contacting a peripheral area of the injection opening of the casing with an inner surface of the injection path by caulking the peripheral area, the peripheral area including the injection opening, and sealing the injection opening by welding a part of the casing contacted.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a heat transport device that transports heat by a phase change of a working fluid, and to a manufacturing method of the same, an electronic apparatus equipped with a heat transport device, and a caulking pin.
2. Description of the Related Art
In the past, a flat-plate heat pipe has been widely used as a device that cools a heat source such as a CPU (central processing unit). A flat-plate heat pipe cools a CPU and the like by using a phase change of a working fluid, and therefore contains a working fluid therein.
For example, Japanese Patent Application Laid-open No. 2007-315745 (hereinafter, referred to as Patent Document 1) discloses a flat-plate heat pipe, on an outer surface of which a refrigerant injection hole and an air outlet hole are formed. In the flat-plate heat pipe, a refrigerant such as water is injected through the refrigerant injection hole, and then a thermoplastic metal having a spherical body, such as solder, is placed at the refrigerant injection hole and the air outlet hole.
Subsequently, the spherical thermoplastic metal is pressurized and deformed at a low temperature, thereby temporarily sealing the refrigerant injection hole and the air outlet hole. After that, the thermoplastic metal is pressurized and deformed at a high temperature, thereby sealing the refrigerant injection hole and the air outlet hole (see, for example, paragraph 0176 of Patent Document 1).

SUMMARY OF THE INVENTION

In the heat pipe disclosed in Patent Document 1, the thermoplastic metal is used as a sealing member for the hole, which has a problem of low reliability of airtightness in the heat pipe. For example, after the heat pipe is formed, in a reflow process for mounting the heat pipe on another member, heat may be applied to the heat pipe in some cases. In this case, the thermoplastic metal as the sealing member may be molten or softened, which may cause a clearance in the hole. Therefore, there is a problem in that the airtightness in the heat pipe is difficult to be maintained.
In view of the above-mentioned circumstances, it is desirable to provide a manufacturing method of a heat transport device that enables to improve airtightness of the inside of a heat transport device, and provide a heat transport device, an electronic apparatus equipped with the same, and a caulking pin.
According to an embodiment of the present invention, there is provided a method of manufacturing a heat transport device including the following steps.
A working fluid that transports heat by a phase change is injected into a casing through an injection opening of the casing under reduced pressure.
An injection path is sealed by caulking under the reduced pressure. The injection path is provided in the casing into which the working fluid is injected and causing the injection opening and an action area in which the phase change of the working fluid occurs to communicate with each other.
A peripheral area of the injection opening of the casing is contacted with an inner surface of the injection path by caulking the peripheral area. The peripheral area includes the injection opening.
The injection opening is sealed by welding a part of the casing contacted.
In this embodiment, the injection path is sealed by caulking under the reduced pressure, that is, the injection path is temporarily sealed before the welding process, with the result that the airtightness of the action area in the casing can be secured before the welding process. Because the contact process and the welding process of the peripheral area of the injection opening are performed in the state where the action area of the airtightness is secured, it is possible to improve the airtightness of the action area in the casing of the product.
The caulking in the sealing of the injection path is linear crushing of the casing. The casing is linearly crushed, with the result that the pressure for the crushing can be larger as compared to a case where the casing is crushed with a plane. Therefore, the airtightness of the injection path after the sealing can be reliably secured. In addition, even in a case where the injection path is short, that is, a distance from the injection opening to the action area is short, the linear sealing can be performed.
The meaning of the linear sealing includes a sealing in a straight line, a curved line, or a line in combination with the straight line and the curved line.
The caulking in the sealing of the injection path is crushing of an area that surrounds the injection opening of the casing. By the crushing process, an inner area in the injection path, which is communicated with the injection opening, is separated from an outer area in the injection path, which is communicated with the injection opening. Thus, at the time of welding, it is possible to suppress an influence of heat given to the outer area in the injection path, which is communicated with the injection opening.
The caulking in the sealing of the injection path may be performed on an area on the injection path outside an area that surrounds the injection opening. That is, because the caulked area is distanced from the injection opening from the injection opening, it is possible to suppress an influence of heat given to the caulked area of the casing at the time of welding.
The contacting may be performed under an atmospheric pressure after the sealing of the injection path. Because the contacting process can be performed under the atmospheric pressure, it becomes easy to manufacture a heat transport device, and it is possible to cut a manufacturing cost.
The contacting is performed simultaneously with the sealing of the injection path. As a result, the number of manufacturing processes can be reduced, and thus time required for the manufacturing can be reduced.
The sealing of the injection path may be crushing of the casing with a blade. By using the blade, the pressure for the crushing can be increased as compared to a case where a member having a flat end surface for crushing the casing is used, with the result that the airtightness is improved.
The blade may be annularly formed in a direction in which the casing is crushed. For example, in a case where an inner diameter of the blade is larger than the width (width in a direction perpendicular to a direction in which the working fluid injected from the injection opening flows) of the injection path, the injection path can be crushed with two lines at the same time, for example. As a result, the airtightness can be realized with higher accuracy at the time of the temporary sealing.
The sealing of the injection path may be crushing of the area that surrounds the injection opening of the casing by using a caulking pin with the injection opening being surrounded with an annular blade of the caulking pin, the caulking pin having the annular blade and a concave portion.
The annular blade is formed in a direction in which the casing is crushed.
The concave portion is formed from the blade and having an inner surface formed vertically from an opening surface of the concave portion that is surrounded by the blade.
Because the inner surface of the concave portion is formed vertically from the opening surface (end surface of the caulking pin) of the concave portion, it is possible to minimize the stress applied to a part of the casing in the concave portion of the caulking pin at the time when the casing is crushed with the caulking pin. Therefore, deformation of the casing in the concave portion is suppressed, and the welding process subsequent thereto can be desirably performed.
Alternatively, the sealing of the injection path may be crushing of the area that surrounds the injection opening of the casing by using a caulking pin with the injection opening being surrounded with an annular blade of the caulking pin, the caulking pin having the annular blade and a concave portion.
The annular blade is formed in a direction in which the casing is crushed.
The concave portion has one of a conical shape and a pyramidal shape tapered with increasing distance from an opening surface of the concave portion that is surrounded by the blade.
The deformation of the part of the casing in the concave portion as described above is prevented depending on the inner diameter of the annular blade, the size of the injection opening, or the material of the casing. Therefore, the concave portion may be formed in the conical or pyramidal shape as in this embodiment.
The conical or pyramidal shape includes a conical and three-or-more-sided pyramidal shape.
The caulking pin may have a convex portion formed in the concave portion toward the opening surface of the concave portion that is surrounded by the blade. As described above, by getting the blade of the caulking pin into the casing, the convex portion functions so as to suppress the deformation of the part of the casing in the concave portion. As a result, the welding process subsequent thereto can be desirably performed.
According to another embodiment of the present invention, there is provided a heat transport device including a working fluid and a casing.
The working fluid transports heat by a phase change.
The casing includes an injection opening for the working fluid, an action area, and an injection path.
In the action area, the phase change of the working fluid occurs.
The injection path causes the injection opening and the action area to communicate with each other and is sealed by caulking.
In the casing, the peripheral area of the injection opening of the casing is formed to be crushed, the peripheral area including the injection opening. The injection opening is sealed by welding the peripheral area of the injection opening with an inner surface of the injection path.
According to another embodiment of the present invention, there is provided an electronic apparatus equipped with the heat transport device described above.
According to another embodiment of the present invention, there is provided a caulking pin of a heat transport device including a casing. The caulking pin crushes the casing. The casing has an injection opening for a working fluid, an action area in which a phase change of the working fluid occurs, and an injection path that causes the injection opening and the action area to communicate with each other. The caulking pin includes an annular blade and a concave portion.
The annular blade is formed in a direction in which the casing is crushed.
The concave portion is formed from the blade and has an inner surface formed from an opening surface of the concave portion that is surrounded by the blade.
According to another embodiment of the present invention, there is provided a heat transport device including a working fluid between a first member and a second member. The heat transport device includes a contact portion and a welding portion.
On the contact portion, the first member and the second member are contacted annularly.
On the welding portion, the first member and the second member are welded inside the contact portion.
As described above, according to the embodiments of the present invention, in the temporary sealing process in the manufacturing process, the airtightness in the casing of the heat transport device can be improved. Further, the airtightness in the casing of the heat transport device as a completed product can also be improved.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of best mode embodiments thereof, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a heat transport device according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view showing the heat transport device taken along a line perpendicular to a longitudinal direction of the heat transport device shown in FIG. 1 (taken along the line A-A of FIG. 1);

FIG. 3 is a perspective view of the heat transport device of FIG. 1 in a manufacturing process;

FIG. 4 is a flowchart of a manufacturing method of the heat transport device shown in FIG. 1;

FIG. 5A is an enlarged plan showing a part of a casing in the vicinity of an injection opening after a diffusion welding is performed, and FIG. 5B is a cross-sectional view of FIG. 5A;

FIG. 6A is a plan view showing an area in the vicinity of the injection opening in a state where the injection opening is temporarily sealed, and FIG. 6B is a diagram for explaining the temporary sealing process;

FIG. 7 is a diagram showing a case where an inner diameter of a temporary sealing groove is smaller than a width of an injection path;

FIG. 8 are diagrams each showing a contacting process in the vicinity of the injection opening by caulking;

FIG. 9 is a diagram showing a sealing process of the injection opening by laser welding;

FIG. 10 is an enlarged plan view showing an area in the vicinity of an injection opening of a heat transport device according to a second embodiment of the present invention;

FIG. 11 is a flowchart showing a manufacturing method of the heat transport device shown in FIG. 10;

FIG. 12 is an enlarged plan view showing an area in the vicinity of an injection opening of a heat transport device according to a third embodiment of the present invention;

FIG. 13 is a perspective view showing a heat transport device according to a fourth embodiment of the present invention in a manufacturing process;

FIG. 14 is a cross-sectional view showing a state where a first flat plate, a flame body, and a second flat plate shown in FIG. 13 are bonded;

FIG. 15 is a perspective view showing a heat transport device according to a fifth embodiment of the present invention in a manufacturing process;

FIG. 16 is a cross-sectional view of a main part of a caulking pin of another mode and the casing of a heat transport device crushed with the caulking pin;

FIG. 17 is a cross-sectional view of a main part of a caulking pin of another mode;

FIG. 18 is a cross-sectional view of a main part of a caulking pin of another mode;

FIG. 19 is a table showing a result of a failure/no-failure test on a leakage at a time when the injection path of the casing is temporarily sealed with a plurality of caulking pins whose end shapes are different;

FIG. 20 are diagrams each showing a three-dimensional shape of a flat plate of the casing crushed by a caulking pin of No. 4 in the table of FIG. 19;

FIG. 21 are diagrams each showing a three-dimensional shape of the flat plate of the casing crushed by a caulking pin of No. 14 in the table of FIG. 19; and

FIG. 22 is a perspective view showing a laptop PC as an electronic apparatus equipped with a heat transport device.

DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment

Structure of Heat Transport Device

FIG. 1 is a perspective view showing a heat transport device 100 according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the heat transport device 100 taken along a line perpendicular to a longitudinal direction of the heat transport device 100 shown in FIG. 1 (taken along the line A-A of FIG. 1). FIG. 3 is a perspective view of the heat transport device 100 in a manufacturing process.
The heat transport device 100 includes a flat plate 1, a capillary member 3, a vapor flow path (not shown), and a dish-like container plate 2 having a concave portion 2 a in which the capillary member 3 and the vapor flow path are contained. The flat plate 1, the capillary member 3, and the container plate 2 are formed into a rectangular shape, for example. The flat plate 1 and the container plate 2 constitute a casing 12 of the heat transport device 100.
In the casing 12, a working fluid (not shown) that transports heat by a phase change is sealed. The capillary member 3 causes a capillary force to act on a liquid-phase working fluid, thereby holding the liquid-phase working fluid. The capillary member 3 and the vapor flow path (not shown) are provided inside the casing 12, that is, provided so as to be approximately filled in the concave portion 2 a of the container plate 2. The area inside the casing 12, that is, an area in which the capillary member 3 and the vapor flow path (not shown) are disposed functions as an action area 8 in which a phase change of the working fluid is caused.
Examples of a material of the flat plate 1 and the container plate 2 include metals such as copper, aluminum, and stainless. Further, examples of a material of the working fluid include ethanol, methanol, acetone, isopropyl alcohol, hydrochlorofluorocarbon, ammonia, and the like.
Typically, the capillary member 3 has a mesh structure with a metal thin wire. In addition to the mesh structure, a structure in which a plurality of wires are bulked may be used. Alternatively, a plurality of members each having the mesh structure may be layered to constitute the capillary member 3.
The vapor flow path (not shown) may be included in the capillary member 3. For example, a cellular mesh, a space between the meshes, or a space between a bottom of the convex portion 2 a and the capillary member 3 may be formed as the vapor flow path.
As a material of the flat plate 1, the container plate 2, and the capillary member 3, a material having high heat conductivity, such as a carbon nanomaterial may be used in addition to the metal described above.
(Action of Heat Transport Device)
A description will be given on actions of the heat transport device 100 structured as described above.
As shown in FIG. 1, on a side of the casing 12 of the heat transport device 100 in a longitudinal direction, a heat source 9 is thermally connected. The “thermally connected” state refers to a directly connected state or a state connected through a heat-conductive member or a heat-conductive sheet-like member (not shown). Typically, the heat source 9 is an IC (integrated circuit) such as a CPU or may be a light source such as a semiconductor laser and an LED.
The heat transport device 100 receives heat of the heat source 9 from the position at which the heat source 9 is disposed, and the working fluid in the liquid phase evaporates, getting into a gas phase. The gas-phase working fluid moves in the casing 12 to a side opposite, in the longitudinal direction, to the side where the heat source 9 is disposed, thereby radiating heat and condensing. The working fluid that has condensed on the side opposite to the side of the heat source 9 is moved in the casing 12 to a heat absorption portion by a capillary force of the capillary member 3. Then, the working fluid receives heat from the heat source 9 and evaporates again. This cycle is repeated, thereby cooling the heat source 9.
(Method of Manufacturing Heat Transport Device)
Next, a description will be given on a method of manufacturing the heat transport device 100. FIG. 4 is a flowchart of the manufacturing method.
As shown in FIG. 3, the plate 1 has an injection opening 1 a for the working fluid, which penetrates the flat plate 1. In the container plate 2, at a position corresponding to the injection opening 1 a, an injection path 2 c for the working fluid is formed. The injection path 2 c is a groove communicated with the action area 8. The diameter of the injection opening 1 a is 0.2 to 0.5 mm, for example.
The injection path 2 c may be formed by, for example, an end-milling process, a laser process, a press process, or a miniaturization process such as a photolithography and a half etching in a semiconductor manufacturing. When the press process is used, a burr is not formed. When the laser process or the end-milling process is used, a mold is unnecessary, and a groove in any form can be formed.
As shown in FIG. 4, in Step S101, the flat plate 1 and the container plate 2 are bonded by diffusion bonding so that the capillary member 3 is sandwiched between the flat plate 1 and the container plate 2. The diffusion bonding refers to bonding by pressing the flat plate 1 and the container plate 2 to each other by pressure while heating them at a predetermined temperature. As shown in FIG. 3, in a case where the thickness of the capillary member 3 is more than the depth of the concave portion 2 a of the container plate 2, the capillary member 3 is pressed and crushed flat. Conditions of a temperature and a pressure at the time of the diffusion bonding differ depending on the material, the shape, or the like of the flat plate 1 and the container plate 2. In this case, the flat plate 1 is bonded to a bonding surface 2 b of the container plate 2. The groove that functions as the injection path 2 c is formed from the bonding surface 2 b.
FIG. 5A is an enlarged plan view showing an area in the vicinity of the injection opening 1 a of the casing 12.
FIG. 5B is a cross-sectional view of FIG. 5A. As shown in the figures, the injection opening 1 a and the injection path 2 c are communicated with each other, thereby causing the injection opening 1 a, the injection path 2 c, and the action area 8 to communicate.
In Step S102, air in the casing 12 is exhausted. The exhaust process and processes of Steps S103 and S104 subsequent thereto are performed in a vacuum chamber (not shown), for example. The vacuum chamber only has to be evacuated to a predetermined degree of vacuum (degree of depressurization), to exhaust air in the casing 12. Instead of the form in which the entire casing 12 is contained in the vacuum chamber, a space around the injection opening 1 a may be locally depressurized by using a dedicated jig.
In Step S103, the working fluid is injected into the casing 12 exhausted. For example, in the vacuum chamber, a container, in which a liquid working fluid is retained, is disposed, and the casing 12 is immersed in the working fluid in the container, thereby injecting the working fluid into the action area 8 through the injection opening 1 a by a predetermined amount. Instead, an injection tool (not shown) may be used for injecting the working fluid into the casing 12.
In Step S104, the injection path 2 c of the casing 12 is sealed by caulking or swaging (temporary sealing). FIG. 6A is a plan view showing the sealed state in the vicinity of the injection opening 1 a. In the temporary sealing process, a temporary sealing groove 1 b is formed in an annular (for example, circular) form so as to surround the injection opening 1 a.
FIG. 6B is a diagram for explaining the temporary sealing process. A caulking pin 20 having, for example, an annular blade 21 presses (caulks) an area surrounding the injection opening 1 a of the casing 12. In other words, the blade 21 surrounds the injection opening 1 a, and a person or a robot presses the caulking pin 20. As a result, the part around the injection opening 1 a is crushed. Consequently, the temporary sealing groove 1 b is formed, thereby shutting off the communication with the injection path 2 c and the action area 8 and sealing the injection path 2 c. The amount of crush by the caulking pin 20 corresponds to an extent that the flat plate 1 is contacted with the inner surface of the injection path 2 c as the groove, and a predetermined degree of vacuum is maintained in the casing 12 even when the casing 12 is under an atmospheric pressure.
In FIGS. 6A and 6B, an inner diameter d1 of the annular blade 21 of the caulking pin 20, which is substantially a diameter d1′ (≦d1) of the temporary sealing groove 1 b, is set to be larger than a width L of the injection path 2 c in a direction perpendicular to a length direction thereof.
The size is not limited to the above. As shown in FIG. 7, a diameter d2 of a temporary sealing groove 1 b′ may be smaller than the width L of the injection path 2 c.
When the blade 21 has the circular form, and the circular temporary sealing groove 1 b′ is formed, the injection opening 1 a can be separated from the action area 8. Therefore, the diameter d2 of the temporary sealing groove 1 b′ may be set to be smaller than the width L as described above.
In addition, when the casing 12 is crushed in an annular form, it becomes unnecessary to crush the entire casing 12 in the direction of the width L in the case where the width L of the injection path 2 c is relatively large, particularly in the form shown in FIG. 7. That is, the size of the area surrounding the injection opening 1 a can be set to be constant irrespective of the width L of the injection path 2 c.
Here, as shown in FIG. 6B, the caulking pin 20 has a concave portion 22 formed by the annular blade 21. An inner surface 22 a of the concave portion 22 is formed vertically from an opening surface 22 b of the concave portion 22 surrounded by the blade 21. That is, the inner surface 22 a of the concave portion 22 is a cylindrical surface. As described above, the inner surface 22 a of the concave portion 22 is formed vertically from the opening surface 22 b, with the result that a stress that can be given to part of the casing 12 in the concave portion 22 of the caulking pin 20 can be reduced as much as possible. Thus, deformation of the part of the casing 12 in the concave portion 22 can be suppressed, and therefore a welding process in Step S106 can be desirably performed.
With reference to FIGS. 8A and 8B, in Step S105, a caulking pin 30 whose shape is different from the shape of the caulking pin 20 used for the temporary sealing is used, and a peripheral area 1 d of the injection opening 1 a, which includes the injection opening 1 a, is crushed. The caulking pin 30 has a flat end surface 31, which crushes the casing 12. The diameter of the caulking pin 30 is larger than the diameter of the injection opening 1 a and smaller than the diameter (inner diameter d1 or d2) of the blade 21 of the caulking pin 20 at the time of the temporary sealing. By the caulking, the peripheral area 1 d of the injection opening 1 a is brought into contact with the inner surface of the injection path 2 c that is opposed to the peripheral area 1 d. This process is performed under the atmospheric pressure.
The peripheral area 1 d of the injection opening 1 a of the casing 12, which includes the injection opening 1 a, refers to an area of the casing 12 within a range that the contacted portion can be welded by caulking with the caulking pin 20. The area is a larger area than the size of the injection opening 1 a in the cross section as shown in FIGS. 8A and 8B, for example. That is, the diameter of the area is substantially close to the width L (see, FIG. 6A) of the injection path 2 c, for example.
In Step S106, as shown in FIG. 9, the peripheral area 1 d including the injection opening 1 a is welded with the inner surface of the injection path 2 c. For the welding, a laser 15 is used, for example. Typically, a YAG (yttrium aluminum garnet) laser is used, but a carbon dioxide laser or another laser may be used. By the welding, the injection opening 1 a is sealed (full-scale sealing).
As described above, in this embodiment, the injection path 2 c is temporarily sealed before the welding process in a vacuum, with the result that the airtightness of the action area 8 in the casing 12 can be secured before the welding process. In this way, the processes (Steps 105 and 106) of contacting and welding of the peripheral area 1 d of the injection opening 1 a, which includes the injection opening 1 a, are performed while securing the airtightness of the action area 8. As a result, the airtightness of the action area 8 in the casing 12 of the product can be improved.
Further, the manufacturing method according to this embodiment provides the following advantage. Although a vacuum welding with a laser generally requires a process time and cost of equipment for the vacuum welding, the welding with the laser can be performed under the atmospheric pressure in this embodiment. Thus, there is an advantage in that the process time can be saved, and the cost of the equipment for the vacuum welding can be eliminated. In addition, the process of Step S105 can also be performed under the atmospheric pressure, so the same advantage as above can be provided.
In this embodiment, the caulking pin 20 having the annular blade 21 crushes the casing 12. That is, the temporary sealing groove 1 b as a circular-lined groove is formed in the casing 12. In this way, because the casing 12 is linearly crushed with the blade 21, the pressure of the crushing can be larger as compared to a case where the casing 12 is crushed with a plane surface. As a result, the airtightness of the injection path 2 c after the sealing can be reliably secured.
In addition, because the caulking pin 20 having the annular blade 21 crushes the casing 12, an area 2 d in the injection path 2 c, which is communicated with the injection opening 1 a is separated from an outer area 2 e (other than the area 2 d) in the injection path 2 c, which is communicated with the injection opening 1 a. Thus, it is possible to suppress an influence of heat given to the outer area 2 e in the injection path 2 c, which is communicated with the injection opening 1 a, at the time of performing the welding with the laser.

Second Embodiment

FIG. 10 is an enlarged plan view showing an area in the vicinity of an injection opening 31 a of a heat transport device 200 according to a second embodiment. In the following, descriptions on the same portions and functions as those of the heat transport device 100 according to the first embodiment shown in FIG. 1 and the like will be simplified or omitted, and descriptions on different points will be mainly given.
An injection path 33 of a casing 32 of the heat transport device 200 has an L-letter shape and is connected to an edge portion 8 a of the action area 8, thereby allowing the injection path 33 and the action area 8 to communicate with each other. Like the heat transport device 100 according to the first embodiment, the heat transport device 200 includes a flat plate 31 having the injection opening 31 a, a container plate having the L-letter shaped injection path 33, and the capillary member 3 (see, FIG. 3).
FIG. 11 is a flowchart showing a manufacturing method of the heat transport device 200. Steps S201 to S203, S205, and S206 are the same as Steps S101 to 103, 105, and 106.
In Step S104, the mode in which the peripheral area of the injection opening 1 a of the casing 12 is shown. On the other hand, in Step S204, a temporary sealing groove 31 b as a crushed area (caulked area) corresponds to an area in the casing 32 other than an area surrounding the injection opening 31 a on the injection path 33. That is, the temporary sealing groove 31 b is distanced from the injection opening 31 a, for example, provided at a position closer not to the injection opening 31 a but to the action area 8. Therefore, it is possible to suppress an influence of heat given to the temporary sealing groove 31 b of the casing 32 at the time of the welding with the laser. Also in Step S204, the caulking pin 20 shown in FIG. 6B may be used.
The heat influence given to the caulked area of the casing refers to an influence of impairing the airtightness due to deformation of the caulked area depending on a welded position with the laser or a heat temperature, for example.
Further, in Step S204, the use of the caulking pin 20 having the annular blade 21 provides the following advantage. For example, in a case where the inner diameter d1 of the blade 21 is larger than the width L of the injection path 33, the injection path 33 can be crushed with two lines at the same time as shown in FIG. 10. As a result, the airtightness at the time of the temporary sealing is realized with higher accuracy.
In this embodiment, in Step S205, a peripheral area of the injection opening 31 a of the casing 32, which includes the injection opening 31 a, is crushed and brought into contact with the inner surface of the injection path 33, as in Step S105. In this case, the peripheral area of the injection opening 31 a of the casing 32, which includes the injection opening 31 a, may be set so that the peripheral area is larger than the injection opening 31 a, and the action area 8 is not crushed in FIG. 10.
In the casing 32 shown in FIG. 10, in a temporary sealing process of the injection path 33, a temporary sealing groove 31 b′ may be formed by a linear crushing along a width direction of the injection path 33. In this case, the line is set to be longer than the width L of the injection path 33. In this way, by linearly crushing the casing 32, the injection path 33 can be temporarily sealed, even if a distance from the injection opening 31 a to the action area 8 is short (if the distance is shorter than the inner diameter d1 of the blade 21 of the caulking pin 20).

Third Embodiment

FIG. 12 is an enlarged plan view showing an area in the vicinity of an injection opening of a heat transport device according to a third embodiment of the present invention. In a case where a linear, elongated injection path 19 shown in the figure is provided to a casing 17, the casing is circularly crushed by the manufacturing method described in the second embodiment, a temporary sealing groove 18 b is formed on a flat plate 18. As a result, the same effect as in the second embodiment can be obtained.

Fourth Embodiment

FIG. 13 is a perspective view showing a heat transport device 300 according to a fourth embodiment of the present invention. FIG. 13 shows a state of the heat transport device 300 in a manufacturing process. The heat transport device 300 includes a first flat plate 26, the capillary member 3, a flame body 27, and a second flat plate 28. FIG. 14 is a cross-sectional view showing a state where the first flat plate 26, the flame body 27, and the second flat plate 28 shown in FIG. 13 are bonded.
The front surface of the flame body 27 is a bonding surface 27 a, which is bonded to the first flat plate 26 by the diffusion bonding. The back surface of the flame body 27 opposite to the front surface is a bonding surface 27 b, which is bonded to the second flat plate 28 by the diffusion bonding. In a rectangular through hole 27 c of the flame body 27, the capillary member 3 and a vapor flow path (not shown) are provided. The first flat plate 26, the flame body 27, and the second flat plate 28 constitute a casing 25.
At an end portion of the second flat plate 28, an injection opening 28 a is formed, and an injection path 28 b as a groove communicated with the injection opening 28 a is formed. The injection path 28 b is formed in an L-letter shape in a plan view. The injection path 28 b is communicated with the action area 8 (see, FIG. 14) at an end portion opposite to the portion where the injection opening 28 a is formed. The action area 8 is an area in which the capillary member 3 is provided within the through hole 27 c of the flame body 27.
The injection path 28 b may be formed by the laser process, the press process, or the end-milling process as described above. In the case of the press process, the surface (surface of the casing) of the second flat plate 28 is protruded.
The heat transport device 300 as described above can be manufactured by the method similar to the processes shown in FIG. 11. For example, in Step S204, the area on the injection path 28 b at the position distanced from the injection opening 28 a is crushed by the caulking pin 20 shown in FIG. 6B, thereby temporarily sealing the injection path 28 b. In Step S205, the peripheral area of the injection opening 28 a of the second flat plate 28, which includes the injection opening 28 a, is crushed, with the result that the peripheral area is brought into contact with the inner surface of the injection path 28 b.
In this case, the inner surface of the injection path 28 b corresponds to the bonding surface 27 b of the flame body 27. In Step S206, the contacted areas are bonded by the laser bonding, thereby sealing the injection opening 28 a.

Fifth Embodiment

In FIG. 13, the structure in which the injection opening 28 a and the injection path 28 b are formed in the second flat plate 28 is shown. Alternatively, as shown in FIG. 15, in a heat transport device 400 according to a fifth embodiment, the injection opening 1 a that passes through the first flat plate 1 is formed in the first flat plate 26 (or a second flat plate 38). Further, in a flame body 37, a groove that functions as an injection path 37 a communicated with the injection opening 1 a and the action area 8 may be formed.
In a case where the injection path 37 a is formed on the flame body 37 by, for example, the press process, a surface of the flame body 37 opposite to the side on which the injection path 37 a is formed is protruded. In this case, it is difficult to bond the flame body 37 and the second flat plate 38 with each other. Accordingly, in this embodiment, the injection path 28 b has to be formed by the laser process or the end-milling process.
(Other Modes of Caulking Pin)
FIG. 16 is a cross-sectional view of a main part of a caulking pin 40 of another mode and the casing 12 of a heat transport device crushed with the caulking pin 40. The caulking pin 40 has an annular blade 41 and a concave portion 42. The concave portion 42 is formed from an opening surface 42 b surrounded by the blade 41. The shape of the concave portion 42 is a conical shape that is tapered with increasing distance from the opening surface 42 b.
The blade 41 of the caulking pin 40 surrounds and crushes the injection opening 1 a of the casing 12, thereby temporarily sealing the injection path 2 c. Because the concave portion 42 of the caulking pin 40 has the conical shape, an area in the vicinity of the injection opening 1 a of the casing 12 is protruded like a part of a sphere as shown in FIG. 16. In other words, in this mode, on a contacted portion 1 e in the injection path 2 c, a stress is applied to the flat plate 1 to be directed toward injection opening 1 a unlike the embodiment shown in FIG. 6B. Depending on the inner diameter of the blade 41 of the caulking pin 40, the size of the injection opening 1 a, or the material of the flat plate 1, deformation of the casing 12 in the concave portion 42 as described above does not occur. Therefore, there is not a problem if the stress is applied toward the injection opening 1 a as shown in FIG. 16 in this mode.
FIG. 17 is a cross-sectional view of a main part of a caulking pin 50 of another mode. The caulking pin 50 has a concave portion 52. The concave portion 52 has a part 52 a of a conical surface and a convex portion 53 formed in the concave portion 52 toward an opening surface 52 b surrounded by the annular blade 51. The shape of the convex portion 53 viewed in an axis direction of the caulking pin 50 is a circle, for example. By using the caulking pin 50, a flat surface like a form obtained by pressing down the spherical surface as shown in FIG. 16 is formed in the vicinity of the injection opening 1 a. As a result, the deformation of the casing 12 to the spherical shape is prevented. Thus, after Step S105, the welding process of Step S106 can be desirably performed.
FIG. 18 is a cross-sectional view of a main part of a caulking pin 60 of another mode. A concave portion 62 of the caulking pin 60 has a side surface 62 a of a cylinder and a convex portion 63 formed in the concave portion 62 toward an opening surface 62 b surrounded by an annular blade 61. The shape of the convex portion 63 viewed in an axis direction of the caulking pin 60 is a circle, for example. With this structure, the surface 62 a as the cylinder surface, which is vertical to the surface of the casing 12, can suppress the deformation of the casing 12 to the sphere in the concave portion 62 at the time of caulking. In addition, the convex portion 63 can enhance the suppression effect thereof.
In the caulking pin 50 shown in FIG. 17, the height of the convex portion 53 in the axis direction may be designed so that the surface of the convex portion 53 is substantially the same as the opening surface 52 b. The same may hold true for the caulking pin 60 shown in FIG. 18. In this case, the temporary sealing process in Step S104 and the contacting process in Step S105 shown in FIG. 4 can be performed at the same time. As a result, the number of the manufacturing processes can be reduced, and the time required for the manufacturing can be saved.
FIG. 19 is a table showing a result of a failure/no-failure test on a leakage at a time when the injection path 2 c of the casing 12 is temporarily sealed with a plurality of caulking pins whose end shapes are different.
The leakage refers to a leakage of air into the casing 12 (action area 8) from the outside of the casing 12 via the injection opening 1 a and the injection path 2 c. The result shows that caulking pins of Nos. 4, 6, 9, and 14 caused no leakage, and were judged to be effective. The caulking pin of No. 4 substantially corresponds to the caulking pin 40 shown in FIG. 16. The caulking pin of No. 14 substantially corresponds to the caulking pin 20 shown in FIG. 6B. In addition to those, it was judged that the caulking pins of Nos. 6 and 9 prevented the leakage and were effective.
FIGS. 20A to 20C are diagrams each showing a three-dimensional shape of the flat plate of the casing 12 crushed by the caulking pin of No. 4 (caulking pin 40 shown in FIG. 16) in the table of FIG. 19. FIG. 20A is a diagram of the flat plate viewed from the surface thereof, FIG. 20B is a diagram of the flat plate viewed from the side surface thereof, and FIG. 20C is a diagram of the flat plate viewed from the back surface thereof (inner surface side of the casing 12).
FIGS. 21A to 21C are diagrams each showing a three-dimensional shape of the flat plate of the casing 12 crushed by the caulking pin of No. 14 (caulking pin 20 shown in FIG. 6B) in the table of FIG. 19. FIG. 21A is a diagram of the flat plate viewed from the surface thereof, FIG. 21B is a diagram of the flat plate viewed from the side surface thereof, and FIG. 21C is a diagram of the flat plate viewed from the back surface thereof (inner surface side of the casing 12).
(Electronic Apparatus)
Next, a description will be given on an electronic apparatus equipped with a heat transport device. Herein, a laptop PC is used as an example of the electronic apparatus.
FIG. 22 is a perspective view showing a laptop PC. A PC 500 includes a main body 70 and a display portion 80.
In a casing of the main body 70, a CPU 90 and a heat transport device 100 are provided. The heat transport device 100 is thermally contacted with the CPU 90.
The electronic apparatus is not limited to the PC 500. Examples of the electronic apparatus include a PDA (personal digital assistant), an electronic dictionary, a camera, a display apparatus, audiovisual equipment, a projector, a printer, a fax machine, a cellular phone, a game machine, a car navigation system, a robot apparatus, and other electronic apparatuses.
The present invention is not limited to the above embodiments, and various other embodiments may be conceived.
The blade of the caulking pin has the circular shape, but may have an oval shape, a triangular or polygonal shape, or a combination thereof. That is, the annular shape may be any shape, as long as the groove is formed completely around the injection opening of the casing.
In FIGS. 16 and 17, the shape of the concave portion of the caulking pin is not limited to the conical shape (part of the conical surface in FIG. 17), and may instead be a three-or-more-sided pyramid. Further, in FIGS. 6B and 18, the inner surface of the concave portion is not limited to the cylindrical surface, and may instead be a side surface of a triangular or polygonal column.
The present application contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2009-092782 filed in the Japan Patent Office on Apr. 7, 2009, the entire content of which is hereby incorporated by reference.

Claims

1. A method of manufacturing a heat transport device, comprising:

injecting a working fluid that transports heat by a phase change into a casing through an injection opening of the casing under reduced pressure;

sealing an injection path by caulking under the reduced pressure, the injection path being provided in the casing into which the working fluid is injected and causing the injection opening and an action area in which the phase change of the working fluid occurs to communicate with each other;

contacting a peripheral area of the injection opening of the casing with an inner surface of the injection path by caulking the peripheral area, the peripheral area including the injection opening; and

sealing the injection opening by welding a part of the casing contacted.

2. The method of manufacturing a heat transport device according to claim 1,

wherein the caulking in the sealing of the injection path is linear crushing of the casing.

3. The method of manufacturing a heat transport device according to claim 2,

wherein the caulking in the sealing of the injection path is crushing of an area that surrounds the injection opening of the casing.

4. The method of manufacturing a heat transport device according to claim 2,

wherein the caulking in the sealing of the injection path is performed on an area on the injection path outside an area that surrounds the injection opening.

5. The method of manufacturing a heat transport device according to claim 2,

wherein the contacting is performed under an atmospheric pressure after the sealing of the injection path.

6. The method of manufacturing a heat transport device according to claim 3,

wherein the contacting is performed simultaneously with the sealing of the injection path.

7. The method of manufacturing a heat transport device according to claim 2,

wherein the sealing of the injection path is crushing of the casing with a blade.

8. The method of manufacturing a heat transport device according to claim 7,

wherein the blade is annularly formed in a direction in which the casing is crushed.

9. The method of manufacturing a heat transport device according to claim 3,

wherein the sealing of the injection path is crushing of the area that surrounds the injection opening of the casing by using a caulking pin with the injection opening being surrounded with an annular blade of the caulking pin, the caulking pin having the annular blade and a concave portion, the annular blade being formed in a direction in which the casing is crushed, the concave portion being formed from the blade and having an inner surface formed vertically from an opening surface of the concave portion that is surrounded by the blade.

10. The method of manufacturing a heat transport device according to claim 3,

wherein the sealing of the injection path is crushing of the area that surrounds the injection opening of the casing by using a caulking pin with the injection opening being surrounded with an annular blade of the caulking pin, the caulking pin having the annular blade and a concave portion, the annular blade being formed in a direction in which the casing is crushed, the concave portion having one of a conical shape and a pyramidal shape tapered with increasing distance from an opening surface of the concave portion that is surrounded by the blade.

11. The method of manufacturing a heat transport device according to claim 9,

wherein the caulking pin has a convex portion formed in the concave portion toward the opening surface of the concave portion that is surrounded by the blade.

12. A heat transport device, comprising:

a working fluid to transport heat by a phase change; and

a casing including an injection opening for the working fluid, an action area in which the phase change of the working fluid occurs, and an injection path that causes the injection opening and the action area to communicate with each other and is sealed by caulking, a peripheral area of the injection opening of the casing being formed to be crushed, the peripheral area including the injection opening, the injection opening being sealed by welding the peripheral area of the injection opening with an inner surface of the injection path.

13. An electronic apparatus equipped with a heat transport device including a working fluid to transport heat by a phase change and a casing having an injection opening for the working fluid, an action area in which the phase change of the working fluid occurs, and an injection path that causes the injection opening and the action area to communicate with each other and is sealed by caulking, a peripheral area of the injection opening of the casing being formed to be crushed, the peripheral area including the injection opening, the injection opening being sealed by welding the peripheral area of the injection opening with an inner surface of the injection path.

14. A caulking pin of a heat transport device including a casing, the caulking pin crushing the casing, the casing having an injection opening for a working fluid, an action area in which a phase change of the working fluid occurs, and an injection path that causes the injection opening and the action area to communicate with each other, the caulking pin comprising:

an annular blade formed in a direction in which the casing is crushed; and

a concave portion formed from the blade and having an inner surface formed from an opening surface of the concave portion that is surrounded by the blade.

15. A heat transport device including a working fluid between a first member and a second member, the heat transport device comprising:

a contact portion on which the first member and the second member are contacted annularly; and

a welding portion on which the first member and the second member are welded inside the contact portion.