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US20210310745A1 - Heat pipe and method for manufacturing same - Google Patents

Heat pipe and method for manufacturing same Download PDF

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Publication number
US20210310745A1
US20210310745A1 US11/993,939 US99393907A US2021310745A1 US 20210310745 A1 US20210310745 A1 US 20210310745A1 US 99393907 A US99393907 A US 99393907A US 2021310745 A1 US2021310745 A1 US 2021310745A1
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US
United States
Prior art keywords
refrigerant
heat pipe
charging hole
main body
cooling unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/993,939
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English (en)
Inventor
Kenji Ohsawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fuchigami Micro Co Ltd
Original Assignee
Fuchigami Micro Co Ltd
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Filing date
Publication date
Application filed by Fuchigami Micro Co Ltd filed Critical Fuchigami Micro Co Ltd
Publication of US20210310745A1 publication Critical patent/US20210310745A1/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0283—Means for filling or sealing heat pipes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0233—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes the conduits having a particular shape, e.g. non-circular cross-section, annular
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
    • F28D15/046—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure characterised by the material or the construction of the capillary structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00

Definitions

  • the present invention relates to a heat pipe and a method for manufacturing the same, and more particularly, a thin and tabular heat pipe.
  • Japanese Unexamined Patent Publications No. 2002-039693 and No. 2004-077120 disclose conventional heat pipes.
  • Such heat pipes have a cooling unit main body that comprises a plurality of superimposed partition plates like thin plates with holes for circulating a refrigerant and outer wall members superimposed on the top and bottom of the superimposed partition plates, and has an interior space for circulating the refrigerant.
  • the refrigerant like water is sealed in the refrigerant circulation space of the cooling unit main body.
  • Sealing of the refrigerant in the cooling unit main body is performed by a scheme of, for example, providing a hole in the side face, the top face, or the bottom face of a heat pipe, charging the refrigerant therein through that hole, and then plugging the hole by caulking or the like.
  • the heat pipes comprise thin tabular members, there is an advantage such that a thin and flat heat pipe can be provided, and further, there are some advantages such that portions of the refrigerant circulation holes overlapped one another serve as flow paths through which the refrigerant passes, the refrigerant moves in displaced portions of the refrigerant circulation holes by capillary phenomenon, and the thermal conductivity is good.
  • Such heat pipes have a heat spread effect several times to several ten times in comparison with a metallic body which is made of a similar metal and has similar contour and volume, and are appropriate for heat radiation of a device where heat dissipation is important, such as a CPU (Central Processing Unit) and an LED (Light Emitting Diode).
  • a CPU Central Processing Unit
  • LED Light Emitting Diode
  • Patent Literature 1 Japanese Unexamined Patent Publication No. 2002-039693
  • Patent Literature 2 Japanese Unexamined Patent Publication No. 2004-077120
  • the refrigerant charging hole is plugged by a sealing member.
  • a possible material of the sealing member is a solder, but in this case, the material of the cooling unit main body (e.g., copper, copper-based material, aluminum, or aluminum-based material) differs from that of the sealing member. This may causes a local battery effect due to the refrigerant which is charged in the cooling unit main body contacts both cooling unit main body and sealing member.
  • the sealing effect may be reduced or dissolved at a high temperature of, for example, 180 to 220° C. or so, and it is desirable to ensure the sealing effect under a high temperature condition.
  • a heat pipe according to the first aspect of the invention comprises:
  • a cooling unit main body that is formed of a metal and has a circulation path for a refrigerant formed in an interior space thereof;
  • a refrigerant charging hole that is formed in the cooling unit main body and is for charging the refrigerant in the interior space
  • a heat pipe according to the second aspect of the invention comprises:
  • a cooling unit main body having a circulation path for a refrigerant formed in an interior space thereof by one or a plurality of intermediate plates provided between an upper plate and a lower plate;
  • a heat pipe according to the third aspect of the invention comprises:
  • cooling unit main body having a circulation path for a refrigerant formed in an interior space thereof;
  • a heat pipe according to the fourth aspect of the invention comprises:
  • a cooling unit main body that is made of a metal and has a circulation path for a refrigerant formed in an interior space thereof by one or a plurality of intermediate plates provided between an upper plate and a lower plate;
  • a refrigerant charging hole that is formed in the cooling unit main body and is for charging the refrigerant in the interior space
  • the sealing member plugging the refrigerant charging hole does not protrude from a surface of the cooling unit main body.
  • the refrigerant charging hole may have a gas venting groove which is formed around an inner periphery surface thereof, causes the interior space to keep communicating with an exterior space until the refrigerant charging hole is completely plugged by the sealing member, and is plugged by the sealing member when the refrigerant charging hole is completely plugged.
  • the circulation path may have a vapor diffusion flow path where the refrigerant vaporizes and diffuses, and the portion corresponding to the refrigerant charging hole is disposed in the vapor diffusion flow path, and the reinforcement member may have a slit formed along a diffusion direction in which the refrigerant vaporizes and diffuses in the vapor diffusion flow path.
  • a heat pipe manufacturing method comprises:
  • a heat pipe manufacturing method comprises:
  • a heat pipe manufacturing method comprises:
  • a heat pipe manufacturing method comprises:
  • a preparation step of preparing a cooling unit main body that is formed of a metal and has a circulation path for a refrigerant formed in an interior space thereof by one or a plurality of intermediate plates provided between an upper plate and a lower plate, the intermediate plate having a reinforcement member which is formed at a portion corresponding to a peripheral region of a refrigerant charging hole formed in the upper plate or the lower plate and has a predetermined thickness, and a hole for the refrigerant formed at a portion corresponding to the refrigerant charging hole;
  • the interior space may keep communicating with an exterior space through a gas venting grove formed at an inner periphery surface of the refrigerant charging hole until the sealing member completely plugs the refrigerant charging hole.
  • the refrigerant charging hole may be tentatively plugged with the sealing member by applying pressure on the sealing member under a vacuum condition, and be completely sealed with the sealing member by heating the sealing member while applying pressure thereon.
  • the heat pipe and the heat pipe manufacturing method of the invention it is possible to provide a heat pipe which can ensure the sealing effect under a high temperature condition, and has a further long life in comparison with the conventional ones.
  • a heat pipe which has an improved productivity, reduces the production cost further, and has a further long life in comparison with the conventional ones.
  • FIG. 1 is a perspective view showing the outline structure of a heat pipe according to the invention
  • FIG. 2A is a cross-sectional view showing the side sectional structure of the heat pipe in FIG. 1 along a line A-A′;
  • FIG. 2B is a cross-sectional view showing the side sectional structure of the heat pipe in FIG. 1 along a line B-B′;
  • FIG. 3A is a schematic diagram showing the planer structure of a top outside surface of an upper plate
  • FIG. 3B is a schematic diagram showing the planer structure of a bottom inside surface of the upper plate
  • FIG. 4A is a schematic diagram showing the planer structure of a bottom outside surface of a lower plate
  • FIG. 4B is a schematic diagram showing the planer structure of a top inside surface of the lower plate
  • FIG. 5 is a schematic diagram showing the planer structure of a first intermediate plate
  • FIG. 6 is a schematic diagram showing the planer structure of a second intermediate plate
  • FIG. 7 is a schematic diagram showing the way how a through hole of the first intermediate plate and through holes of the second intermediate plate are arranged
  • FIG. 8 is a schematic diagram showing the structures of vapor diffusion flow paths and capillary flow paths both formed by the first and second intermediate plates;
  • FIG. 9A is a detailed cross-sectional view showing a way ( 1 ) how refrigerant circulating phenomenon occurs;
  • FIG. 9B is a detailed cross-sectional view showing a way ( 2 ) how refrigerant circulating phenomenon occurs;
  • FIG. 10 is a schematic diagram showing the way how the refrigerant spreads toward the peripheral portion from the center;
  • FIG. 11 is a schematic diagram showing the way how the refrigerant returns to the center from the peripheral portion
  • FIG. 12A represents a front view showing the partial detailed structure of a region near a refrigerant charging hole formed in the bottom inside surface of the upper plate, and a cross-sectional view along a line C-C′ in that front view;
  • FIG. 12B a front view showing the partial detailed structure ( 1 ) of a region near an intermediate plate reinforcement member formed at the first intermediate plate;
  • FIG. 12C is a front view showing the partial detailed structure ( 1 ) of a region near a slit-provided reinforcement member formed at the second intermediate plate;
  • FIG. 12D is a front view showing the partial detailed structure ( 2 ) of a region near the intermediate plate reinforcement member formed at the first intermediate plate;
  • FIG. 12E is a front view showing the partial detailed structure ( 2 ) of a region near the slit-provided reinforcement member formed at the second intermediate plate;
  • FIG. 12F is a front view showing the partial detailed structure of a region near a lower plate reinforcement member formed at the top inside surface of the lower plate;
  • FIG. 13 is a cross-sectional view showing the respective detailed structures of an upper plate reinforcement member, intermediate plate reinforcement member, slit-provided reinforcement member, and lower plate reinforcement member;
  • FIG. 14A is a cross-sectional view showing an example (1) of a heat pipe manufacturing method
  • FIG. 14B is a cross-sectional view showing the example (2) of the heat pipe manufacturing method
  • FIG. 14C is a cross-sectional view showing the example (3) of the heat pipe manufacturing method
  • FIG. 14D is a cross-sectional view showing the example (4) of the heat pipe manufacturing method
  • FIG. 14E is a cross-sectional view showing the example (5) of the heat pipe manufacturing method
  • FIG. 15A is a schematic diagram showing the planer structure of the refrigerant charging hole
  • FIG. 15B is a schematic diagram showing the way how a sealing member is disposed on the refrigerant charging hole
  • FIG. 15C is a schematic diagram showing the way how the refrigerant charging hole is plugged by the sealing member
  • FIG. 16A is a cross-sectional view showing the example (6) of the heat pipe manufacturing method
  • FIG. 16B is a cross-sectional view showing the example (7) of the heat pipe manufacturing method
  • FIG. 17 is a schematic diagram showing the way how the refrigerant is supplied into the cooling unit main body using an inkjet nozzle
  • FIG. 18 is a schematic diagram showing the structure of a slit-provided reinforcement member according to another embodiment
  • FIG. 19 is a schematic diagram showing the structure of a slit-provided reinforcement member according to another embodiment.
  • FIG. 20A is a schematic diagram showing a planer structure ( 1 ) of a refrigerant charging hole or an air outlet port according to the other embodiment of the invention.
  • FIG. 20B is a schematic diagram showing a side sectional structure ( 1 ) of the refrigerant charging hole or the air outlet port according to the other embodiment
  • FIG. 20C is a cross-sectional view showing a way ( 1 ) how the refrigerant charging hole or the air outlet port according to the other embodiment are plugged by the sealing member;
  • FIG. 21A is a schematic diagram showing a planer structure ( 1 ) of a refrigerant charging hole or an air outlet port according to a further other embodiment of the invention.
  • FIG. 21B is a cross-sectional view showing a side sectional structure ( 2 ) of the refrigerant charging hole or the air outlet port according to the further other embodiment.
  • FIG. 21C is a cross-sectional view showing a way ( 2 ) how the refrigerant charging hole or the air outlet port are plugged by the sealing member.
  • a refrigerant is charged in the interior space of a cooling unit main body in which a refrigerant charging hole is formed, a sealing member made of the same or similar plastic metal to the cooling unit main body is disposed on the refrigerant charging hole, and then the refrigerant charging hole is sealed with the sealing member by pressurization under a vacuum condition. Further, to ensure the sealing effect by the sealing member, the sealing member is fixed by heating while applying pressure, thereby manufacturing a heat pipe having the refrigerant charging hole completed sealed.
  • the heat pipe has the cooling unit main body formed of a metal and the sealing member formed of the same or similar plastic metal to the cooling unit main body, a local battery effect due to both of the cooling unit main body and the sealing member does not occur even if both cooling unit main body and sealing member contact the refrigerant or exposed thereto, and corrosion inherent to a local battery effect is prevented, thereby making the heat pipe further long-lived in comparison with the conventional ones.
  • the melting point thereof is high, so that the sealing effect can be obtained under a high temperature condition of 200 to 300° C. or so in comparison with a solder. Therefore, the sealing effect is ensured under a high temperature condition.
  • a heat pipe has a cooling unit formed by sandwiching one or a plurality of tabular intermediate plates between tabular upper and lower plates.
  • the cooling unit main body one or the plurality of intermediate plates form a circulation path that is constituted by flow paths which cause a vapor to diffuse toward the peripheral portion of the cooling unit main body (hereinafter, these flow paths are called vapor diffusion flow path), and flow paths which cause the refrigerant to flow in a vertical and oblique directions by capillary phenomenon (hereinafter, those flow paths are called capillary flow paths) with a direction between the upper and lower plates taken as the vertical direction.
  • Recessed grooves are formed in the bottom inside surface of the upper plate in a grid pattern, and recessed grooves are also formed in the upper inside surface of the lower plate in a grid pattern.
  • the vapor diffusion flow paths are communicated with the capillary flow paths through the recessed grooves formed in the bottom inside surface of the upper plate (hereinafter called upper-plate-inside-surface groove portion) and the recessed grooves formed in the top inside surface of the lower plate (hereinafter called lower-plate-inside-surface groove portion).
  • Projecting poles each of which has a leading end formed in a planer shape are formed at individual regions partitioned by the upper-plate-inside-surface groove portion and the lower-plate-inside-surface groove portion. Because the leading end of each projecting pole is formed in a planer shape, the projecting poles can adhere tightly to an intermediate plate.
  • the upper-plate-inside-surface groove portion and the lower-plate-inside-surface groove portion are formed in a grid pattern in the following embodiments, but may be formed in other patterns like a mesh pattern.
  • the projecting pole is formed in such a manner as to have a transverse section formed in a square, circular, elliptical, polygonal, or a star shape.
  • the vapor diffusion flow path may be formed in a band-like shape, trapezoidal shape, or in such a shape that the width thereof becomes large or narrow from the center toward the peripheral portion.
  • the vapor diffusion flow path may be formed in various other shapes.
  • overlapped holes for the vapor diffusion flow paths may be completely overlapped one another, or may be displaced in a width direction.
  • the through holes themselves serve as the vapor diffusion flow paths.
  • each intermediate plate When the plurality of intermediate plates are used, by overlapping the plurality of intermediate plates one another, overlapped through holes form the capillary flow paths communicating with the vapor diffusion flow paths.
  • the through holes of each intermediate plate may be formed in different patterns for each intermediate plate, and may be formed in the same pattern for all intermediate plates. When one intermediate plate is used, the through holes themselves serve as the capillary flow paths.
  • the intermediate plates may be provided between the upper plate and lower plate in such a way that the positions, shapes and sizes of the through holes of the respective intermediate plates coincide to thereby constitute capillary flow paths having the same position, shape and size as the through hole of each intermediate plate.
  • the through hole or the resultant capillary flow path may have a rectangular shape (e.g., square or oblong shape), of which the corners may be rounded.
  • a part or whole sides thereof may be corrugated or wrinkled so as to enlarge a surface area thereof, because a cooling effect is enhanced if the peripheral inside surface area of the capillary flow path is large.
  • the capillary flow path may take a hexagonal, circular or elliptical shape.
  • the plural intermediate plates may be suitably displaced from the positions where the respective through holes are precisely aligned with one another so as to be only partially overlapped, thereby enabling the substantive cross-sectional area of the capillary flow path to be made small as compared with the cross-sectional area of the through hole of each intermediate plate.
  • the two intermediate plates when the two intermediate plates are used, it is possible to reduce the substantive cross-sectional area of the capillary flow path to about 1 ⁇ 2 of that of the through hole of each intermediate plate, by displacing the respective intermediate plates by a half pitch of an arrangement pitch in a predetermined direction (e.g., lateral direction, (one side direction when the through hole is formed in a rectangular shape)), with the size, shape and arrangement pitch of each through hole being kept the same. Furthermore, if the positions of the through holes of the two intermediate plates are also displaced in a direction intersecting with the foregoing side direction (e.g., longitudinal direction.
  • a predetermined direction e.g., lateral direction, (one side direction when the through hole is formed in a rectangular shape
  • the substantial cross-sectional area of the capillary flow path can be reduced to about 1 ⁇ 4 of that of the through hole of each intermediate plate.
  • Suitable materials of the cooling unit main body, upper plate, lower plate and intermediate plates which constitute the cooling unit main body, and sealing member which plugs the refrigerant charging hole are copper, and copper-based metal like copper alloy, but the materials are not limited to those metals, and for example, aluminum and aluminum-based metal containing aluminum like aluminum alloy which have an advantage such that the material cost thereof is low, iron and iron-based metal like iron alloy, stainless steel, gold, silver may be used.
  • the outside surface of the cooling unit main body including the surface of the sealing member made of copper or a copper-based metal is normally undergone nickel plating.
  • Water e.g., pure water, distilled water having a large latent heat is suitable as the refrigerant, but the refrigerant is not limited to water, and, for example, ethanol, methanol, acetone, or the like is also suitable.
  • the refrigerant charging hole is constituted by an opening which is plugged by the disposed sealing member, and gas venting grooves, so that a gas in the cooling unit main body is taken out through the gas venting grooves in performing a plugging work with the sealing member.
  • the heat pipe when the refrigerant charging hole is sealed by the sealing member, vacuum deaeration can be performed through the gas venting grooves, and if a harmful component which causes the cooling unit main body to be corroded is present thereinside, air inside the cooling unit main body can be taken out through the gas venting grooves, so that the harmful component can be surely removed from the interior space of the cooling unit main body together with the air.
  • the sealing member formed of a plastic metal performs plastic deformation, is fixed by pressure, and becomes a sealing plug by heating and pressurization. Therefore, according to the heat pipe, the gas venting grooves can be surely plugged by the sealing member, resulting in complete closing of the refrigerant charging hole, so that the refrigerant is sealed in the cooling unit main body, and it is possible to surely prevent the refrigerant from leaking.
  • the cooling unit main body may be provided with an air outlet port which have, for example, the same size as that of the refrigerant charging hole, and in this case, when the refrigerant is charged through the refrigerant charging hole, air in the cooling unit main body is taken out through the air outlet port, thereby making the charging of the refrigerant more smooth.
  • the refrigerant may be supplied using a normal nozzle, but by using an inkjet nozzle, the refrigerant may be made into minute particles and charged in the cooling unit main body in a misty form.
  • the refrigerant may be supplied while keeping the nozzle away from the cooling unit main body so as not to contact the cooling unit main body.
  • Charging of the refrigerant through the refrigerant charging hole is possible without forming the air outlet port in the cooling unit main body, but formation of the air outlet port is preferable because the charging of the refrigerant becomes smooth.
  • plugging by the sealing member is performed not only on the refrigerant charging hole, but also on the air outlet port.
  • Possible nozzles which supply the refrigerant in a misty form are an inkjet nozzle, a micro dispenser which makes the refrigerant into tiny particles, and a nanoliter level dispenser which makes the refrigerant into ultrafine particles.
  • miniaturization of a device to be cooled, thinning and miniaturization of the cooling unit main body associated with the thinning are requested for such a heat pipe, but the strength becomes week if such requests are merely satisfied, so that breakage may occur when the refrigerant charging hole of the cooling unit main body is plugged by a metallic body like copper, and when the heat pipes are in use.
  • an intermediate plate which is provided in the interior space of the cooling unit main body has a reinforcement member having a predetermined thickness and provided at a portion corresponding to the peripheral region of the refrigerant charging hole, the mechanical strength at the peripheral region of the refrigerant charging hole is improved, and occurrence of a breakage in manufacturing and in using the heat pipe can be prevented, thereby improving the productivity in comparison with the conventional ones, reducing the manufacturing cost, and making the heat pipe further long-lived.
  • the reinforcement members are stacked one another, adhere tightly to form a support structure, thereby further improving the mechanical strength at the peripheral region of the refrigerant charging hole. Note that some of the intermediate plates may be provided with the reinforcement members.
  • the reinforcement member When the reinforcement member is provided at a portion corresponding to the peripheral region of the refrigerant charging hole, it is preferable that the reinforcement member should have a hole for the refrigerant which is communicated with the refrigerant charging hole and is formed at a portion corresponding to the refrigerant charging hole. This makes it possible to cause the refrigerant to spread across the intermediate plate and the lower plate evenly through the refrigerant hole and slits when the refrigerant is charged in the interior space through the refrigerant charging hole.
  • the slits may be formed along a diffusion direction in which the refrigerant vaporizes and passes through the vapor diffusion flow paths. This enables the refrigerant, which vaporizes and diffuse the vapor diffusion flow paths, to spread to the peripheral portion without being interrupted by the reinforcement member, thereby ensuring the heat dissipation effect.
  • All reinforcement members of the intermediate plates may have slits, respectively, but some of the reinforcement members may have the slits.
  • FIG. 1 shows the outline structure of a top outside surface of a heat pipe 1 according to an embodiment.
  • the heat pipe 1 has an upper plate 2 and a lower plate 3 both made of a copper-based metal having a high thermal conductivity, such as copper, or copper alloy, and a refrigerant charging hole 4 and an air outlet port 5 are formed in a top outside surface 2 a of the upper plate 2 .
  • the refrigerant charging hole 4 is formed near one corner portion in a pair of diagonal corner portions, while the air outlet port 5 is formed near the other corner portion diagonally opposite to the one corner portion.
  • the refrigerant charging hole 4 and the air outlet port 5 are plugged by sealing members 8 each of which is formed of the same copper-based metal as those of the upper plate 2 and the lower plate 3 .
  • the heat pipe 1 has a cooling target device HE which is a heat generating body, such as an IC (semiconductor Integrated Circuit), an LSI (Large Scale Integrated circuit), or a CPU and is attached to the bottom outside surface of the lower plate 3 .
  • a cooling target device HE is a heat generating body, such as an IC (semiconductor Integrated Circuit), an LSI (Large Scale Integrated circuit), or a CPU and is attached to the bottom outside surface of the lower plate 3 .
  • a second intermediate plate 7 a , a first intermediate plate 6 a , a second intermediate plate 7 b and a first intermediate plate 6 b are stacked on the lower plate 3 in this order, the upper plate 2 is stacked on the first intermediate plate 6 b , those plates are positioned by non-illustrated positioning holes, directly joined and integrated together, thereby forming a cooling unit main body 10 .
  • the first intermediate plates 6 a , 6 b and the second intermediate plates 7 a , 7 b are stacked alternately, thereby forming vapor diffusion flow paths 44 which extend radially from a region opposite to that portion where the cooling target device HE is provided and the peripheral region 33 a thereof (hereinafter, those regions are collectively called cooling-target-device peripheral region) toward a peripheral portion 12 as shown in FIG. 2A , and minute capillary flow paths 42 shown in FIG. 2B in an interior space 10 a of the cooling unit main body 10 .
  • FIG. 2A is a cross-sectional view of that region where the interior of the cooling unit main body 10 is partitioned into the capillary flow paths 42 and the vapor diffusion flow paths 44
  • FIG. 2B is a cross-sectional view of that region where the interior space of the cooling unit main body 10 is filled with the capillary flow paths 42 .
  • a predetermined amount of refrigerant W comprising water is sealed in the interior space 10 a of the cooling unit main body 10 under a depressurized condition, so that the boiling point of the refrigerant W is dropped, and the refrigerant W is vaporized by a slight amount of heat from the cooling target device HE and circulates the vapor diffusion flow paths 44 and the capillary flow paths 42 .
  • FIG. 3A shows the structure of the top outside surface 2 a of the upper plate 2
  • FIG. 3B shows the structure of a bottom inside surface 2 b of the upper plate 2
  • FIG. 4A shows the structure of a bottom outside surface 3 a of the lower plate 3
  • FIG. 4B shows the structure of a top inside surface 3 b of the lower plate 3 .
  • FIG. 5 shows the structure of the first plate 6 a , 6 b , sandwiched between the upper plate 2 and the lower plate 3
  • FIG. 6 shows the structure of the second intermediate plate 7 a , 7 b sandwiched between the upper plate 2 and the lower plate 3 like the first intermediate plate 6 a , 6 b.
  • the upper plate 2 has a main body 21 having a thickness of, for example, 500 ⁇ m, and formed in an almost square shape.
  • the main body 21 has an upper-plate-inside-surface groove portion 23 recessed and formed in a grid pattern and formed at the bottom inside surface 2 b other than the peripheral portion 12 formed in a frame-like shape.
  • the upper plate 2 has projecting poles 24 each having a planer leading end are provided at individual regions partitioned in a grid pattern by the upper-plate-inside-surface groove portion 23 .
  • the lower plate 3 has a tabular main body 11 having a thickness of, for example, 500 ⁇ m and formed in an almost square shape like the upper plate 2 .
  • the main body 11 has a lower-plate-inside-surface groove portion 14 recessed and formed in a grid pattern and formed at the top inside surface 3 b other than the peripheral portion 12 formed in a frame-like shape.
  • the lower plate 3 has projecting poles 15 each having a planer leading end are formed at individual regions partitioned in a grid pattern by the lower-plate-inside-surface groove portion 14 .
  • a main body 31 of the first intermediate plate 6 a , 6 b shown in FIG. 5 and a main body 32 of the second intermediate plate 7 a , 7 b shown in FIG. 6 are made of the same copper-based metals as those of the upper plate 2 and the lower plate 3 , have a thickness of, for example, 70 to 200 ⁇ m, and are formed in an almost square shape like the main body 11 of the lower plate 3 .
  • the first intermediate plate 6 a has holes 34 for vapor diffusion flow paths and a capillary formation region 36 formed in the main body 31 .
  • the capillary formation region 36 comprises a cooling-target-device peripheral region 33 a and regions 33 b which are regions between the adjoining vapor diffusion flow path holes 34 and are regions other than the cooling-target-device peripheral region 33 a .
  • the cooling-target-device peripheral region 33 a faces the cooling target device IE provided on the lower plate 3 when the main body 31 is stacked on the main body 11 of the lower plate 3 .
  • the vapor diffusion flow path holes 34 each formed in a band-like shape extend radially from the cooling-target-device peripheral region 33 a including the four corners.
  • a plurality of through holes 37 for forming the capillary flow paths 42 are formed in the capillary formation region 36 in a first pattern (to be discussed later).
  • the capillary formation region 36 has grid-like partition walls 38 , and the individual region partitioned by the partition walls 38 serve as the through holes 37 .
  • the through holes 37 each formed in a rectangular shape are arranged regularly at predetermined intervals as the first pattern, and have four sides parallel to the respective sides of the peripheral portion 12 of the main body 32 ( FIG. 5 ).
  • the width of a through hole 52 is selected to 280 ⁇ m or so, and the width of a partition wall 38 is selected to 70 ⁇ m or so.
  • the second intermediate plate 7 a , 7 b shown in FIG. 6 is formed to have the same size as that of the first intermediate plate 6 a , 6 b .
  • An explanation will be given of only the second intermediate plate 7 a in the second intermediate plates 7 a , 7 b .
  • the second intermediate plate 7 a is provided with a capillary formation region 36 and holes 34 for vapor diffusion flow paths like the first intermediate plates 6 a , 6 b , but a plurality of through holes 40 formed in the capillary formation region 36 are formed in a second pattern (to be discussed later) which is different from the first pattern.
  • the capillary formation region 36 of the second intermediate plate 7 a has grid-like partition walls 41 , and the individual regions partitioned by the partition walls 41 serve as the through holes 40 .
  • the through holes 40 each formed in a rectangular shape are arranged regularly at predetermined intervals as the second pattern like the first pattern, and have four sides parallel to the respective sides of the peripheral portion 12 of the main body 32 , and are displaced from the individual through holes 37 of the first intermediate plate 6 a at predetermined distances.
  • a through hole 37 of the first intermediate plate 6 a is displaced in an X direction of one side of a through hole 40 of the second intermediate plate 7 a by half of that side, and in a Y direction of the other side orthogonal to the X direction by half of the other side.
  • This allows a through hole 37 of the first intermediate plate 6 a to overlap four adjoining through holes 40 of the second intermediate plate 7 a , thereby forming the four capillary flow paths 42 . Accordingly, this enables lots of capillary flow paths 42 , which are much smaller than the through holes 37 , 40 , partitioned minutely and have small surface areas, to be formed in one through hole 37 .
  • the heat pipe 1 by stacking the second intermediate plates 7 a , 7 b and the first intermediate plates 6 a , 6 b alternately, the through holes 37 , 40 are displaced one another, the capillary flow paths 42 are formed, the vapor diffusion flow path holes 34 are overlapped, and the vapor diffusion flow paths 44 are formed.
  • the vapor diffusion flow paths 44 and the capillary flow paths 42 are communicated with one anther through the upper-plate-inside-surface groove portion 23 and the lower-plate-inside-surface groove portion 14 ( FIGS. 2A, 2B ).
  • FIG. 9A which shows the side sectional structure of that portion where the vapor diffusion flow paths 44 and the capillary flow paths 42 are formed, along a line A-A′ in FIG. 1 , because the refrigerant W is always present in the individual capillary flow paths 42 in the cooling-target-device peripheral region 33 a , the refrigerant W in the individual capillary flow paths 42 rapidly and surely absorbs heat conducted from the projecting portions of the cooling-target-device peripheral region 33 a and starts vaporizing, and diffuses the vapor diffusion flow paths 44 which extend to the peripheral portion 12 , the upper-plate-inside-surface groove portion 23 and the lower-plate-inside-surface groove portion 14 .
  • the refrigerant W diffuses radially and uniformly around the cooling target device HE provided on the lower plate 3 along the vapor diffusion flow paths 44 , the upper-plate-inside-surface groove portion 23 , and the lower-plate-inside-surface groove portion 14 , and moves to the peripheral portion 12 .
  • FIG. 9B which shows the side sectional structure of a portion which is filled with the capillary flow paths 42 along a line B-B′ in FIG. 1
  • the refrigerant W which is undergone heat dissipation condensation and is liquefied at the upper-plate-inside-surface groove portion 23 , the lower-plate-inside-surface groove portion 14 , the peripheral portion 12 , and the like enters into the capillary flow paths 42 from upper-plate-inside-surface groove portion 23 , the lower-plate-inside-surface groove portion 14 , passes through the capillary flow paths 42 , and returns to the cooling-target-device peripheral region 33 a .
  • FIG. 11 which shows the planer structure of the first intermediate plate 6 a
  • the refrigerant W passes through the capillary flow paths 42 radially arranged in the regions 33 b , and evenly cools the cooling target device HE from the periphery thereof.
  • FIG. 12A represents a front view showing the partial detailed structure of the vicinity region of the refrigerant charging hole 4 formed in the bottom inside surface 2 b of the upper plate 2 , and a cross-sectional view along a line C-C′ in the front view.
  • the bottom inside surface 2 b of the upper plate 2 is provided with a circular upper plate reinforcement member 50 formed at the peripheral region of the refrigerant charging hole 4 in such a manner as to surround the refrigerant charging hole 4 .
  • the upper plate reinforcement member 50 is thicker than the upper-plate-inside-surface groove portion 23 , and is set to the same thickness as that of the projecting pole 24 provided between the grooves of the upper-plate-inside-surface groove portion 23 and the peripheral portion 12 .
  • the refrigerant charging hole 4 is a minute hole whose circular opening 4 a at the center has a diameter of 500 to 1000 ⁇ m or so, has gas venting grooves 4 b formed around the inner periphery surface thereof, and a recessed portion 4 c which enables stable disposition of the spherical sealing member 8 on the opening 4 a and the gas venting grooves 4 b.
  • each gas venting groove 4 b is formed in a semi-spherical shape having a smaller diameter than that of the opening 4 a , and the four gas venting grooves 4 b are provided around the inner periphery surface of the opening 4 a at equal intervals.
  • FIGS. 12B and 12D are front views showing the partial detailed structures of a region in the vicinity of an intermediate plate reinforcement member 52 formed at the first intermediate plate 6 a , 6 b .
  • the intermediate plate reinforcement member 52 of the first intermediate plate 6 a is formed in a circular shape which is the same shape as that of the upper plate reinforcement member 50 , and is formed at a location corresponding to the upper plate reinforcement member 50 .
  • the intermediate plate reinforcement member 52 is formed in the vapor diffusion flow path hole 34 , formed integral with the partition walls 38 , and partitions the corner portion of the vapor diffusion flow path hole 34 .
  • the intermediate plate reinforcement member 52 is set to the same thickness as those of the partition wall 38 and the peripheral portion 12 , and a hole 53 for the refrigerant is formed in a location corresponding to the opening 4 a of the refrigerant charging hole 4 of the upper plate 2 .
  • FIGS. 12C and 12E are front views showing the partial detailed structure of a region in the vicinity of a slit-provided reinforcement member 55 formed at the second intermediate plate 7 a , 7 b .
  • the slit-provided reinforcement member 55 of the second intermediate plate 7 a , 7 b is formed integral with the partition walls 41 , and has the same structure as that of the intermediate plate reinforcement member 52 of the first intermediate plate 6 a , 6 b , but has slits 56 each formed in such a manner as to communicate with the vapor diffusion flow path hole 34 .
  • a hole 57 for the refrigerant is formed in a location corresponding to the opening 4 a of the refrigerant charging hole 4 of the upper plate 2 , and is communicated with the slits 56 .
  • the slit-provided reinforcement member 55 has the slits 56 formed along a diffusion direction D in which a vapor in the vapor diffusion flow path hole 34 diffuses (i.e., direction from the center of the second intermediate plate 7 a , 7 b toward the corner portion thereof), and is communicated with the vapor diffusion flow path hole 34 so that the vapor can diffuses and reaches the corner portion.
  • Each slit 56 is formed linearly, and has a width of 0.3 mm or so.
  • FIG. 12F is a front view showing the partial detailed structure of a region in the vicinity of a lower plate reinforcement member 60 formed at the top inside surface 3 b of the lower plate 3 .
  • the top inside surface 3 b of the lower plate 3 has the circular lower plate reinforcement member 60 formed at a region corresponding to the intermediate plate reinforcement member 52 and the slit-provided reinforcement member 55 .
  • the lower plate reinforcement member 60 has a thicker thickness than that of the lower-plate-inside-surface groove portion 14 and the same thickness as those of the projecting pole 15 provided between the grooves of the lower-plate-inside-surface groove portion 14 and the peripheral portion 12 .
  • the lower plate reinforcement member 60 has slit-opposing grooves 61 which are communicated with the lower-plate-inside-surface groove portion 14 and a central recess portion 62 .
  • the slit-opposing groove 61 has a width of 300 ⁇ m or so, and is formed linearly at the lower plate reinforcement member 60 in such a manner as to oppose the slits 56 .
  • the central recess portion 62 is formed circularly at a portion corresponding to the opening 4 a of the refrigerant charging hole 4 of the upper plate 2 .
  • FIG. 13 is a cross-sectional view showing the detailed structures of the upper plate reinforcement member 50 , intermediate plate reinforcement member 52 , slit-provided reinforcement member 55 and lower plate reinforcement member 60 when the second intermediate plate 7 a , the first intermediate plate 6 a , the second intermediate plate 7 b and the first intermediate plate 6 b are stacked together on the lower plate 3 in this order and the upper plate 2 is staked on the first intermediate plate 6 b.
  • the upper plate reinforcement member 50 , the intermediate plate reinforcement member 52 , the slit-provided reinforcement member 55 and the lower plate reinforcement member 60 adhere together to form a support structure below the peripheral region of the refrigerant charging hole 4 of the upper plate 2 , resulting in improvement of the mechanical strength.
  • Refrigerant particles W 1 which are successively delivered into the refrigerant charging hole 4 in a droplet form one by one from a nozzle 70 at a high speed (e.g., 1000 droplets per second) pass through the opening 4 a of the upper plate 2 , the hole 53 of the first intermediate plate 6 b , the hole 57 of the second intermediate plate 7 b , and the like, reach the slit-opposing grooves 61 and the central recessed portion 62 of the lower plate 3 , and spread across the entire interior space 10 a ( FIG. 2A ) of the cooling unit main body 10 through the slits 56 .
  • a high speed e.g. 1000 droplets per second
  • FIGS. 14A to 14E and FIGS. 16A and 16B shows an example of the manufacturing method of the heat pipe 1 , and as shown in FIG. 14A , first, the second intermediate plate 7 a , the first intermediate plate 6 a , the second intermediate plate 7 b , the first intermediate plate 6 , and the upper plate 2 are stacked on the lower plate 3 in this order.
  • the first intermediate plate 6 a , 6 b and the second intermediate plate 7 a , 7 b have joining projections 72 which protrude from the respective top face thereof and are formed in a frame-like pattern along the respective peripheral portion 12 .
  • the lower plate 3 has a joining projection 73 which protrudes from the top inside surface 3 b of the main body 11 and is formed in a frame-like pattern along the peripheral portion 12 .
  • the second intermediate plate 7 a , the first intermediate plate 6 a , the second intermediate plate 7 b , the first intermediate plate 6 b and the upper plate 2 are overlapped at the most appropriate position, stacked on the lower plate 3 , heated at a temperature lower than or equal to the melting point, and pressurized to directly join those plates together through the joining projections 72 , 73 .
  • the cooling unit main body 10 has the interior space 10 a which is communicated with the exterior space through the refrigerant charging hole 4 and the air outlet port 5 both formed in the upper plate 2 .
  • Each of the first intermediate plates 6 a , 6 b , second intermediate plates 7 a , 7 b , and lower plate 3 has a projection 74 provided at the four-side contour position of the central portion facing the cooling target device HE, and direct joining for integration is obtained not only at the peripheral portions 12 but also at the contour position of the cooling-target-device peripheral region 33 a through the projections 74 .
  • the cooling unit main body 10 also has a support structure at the cooling-target-device peripheral region 33 a to improve the mechanical strength, and this prevents the cooling unit main body 10 from being damaged due to phenomenon such that the refrigerant thermally expands due to heat generated from the cooling target device HE and causes the central portion of the cooling unit main body 10 to expand outwardly (hereinafter, this phenomenon is called Popcorn phenomenon).
  • the overlapped vapor diffusion flow path holes 34 of the respective first intermediate plates 6 a , 6 b , and second intermediate plates 7 a , 7 b form the vapor diffusion flow paths 44
  • the overlapped capillary formation regions 36 form the plurality of capillary flow paths 42 , thereby forming a circulation path constituted by the vapor diffusion flow paths 44 and the capillary flow paths 42 ( FIGS. 9A and 9B ).
  • the upper plate reinforcement member 50 , the intermediate plate reinforcement member 52 , the slit-provided reinforcement member 55 and the lower plate reinforcement member 60 adhere tightly, thereby forming a support structure below the regions around the refrigerant charging hole 4 and the air outlet port 5 .
  • the predetermined amount of refrigerant W 1 (e.g., water) is charged in the interior space 10 a of the cooling unit main body 10 through the refrigerant charging hole 4 using the nozzle 70 under an atmospheric pressure.
  • the air outlet port 5 serves as the exhaust port of air, thereby making the charging of the refrigerant into the interior space 10 a smooth.
  • the charging amount thereof should be almost equal to the total volume of the through holes 37 , 40 , and ultrapure water having no ion contamination is preferable for the longer life of the heat pipe 1 .
  • vacuuming is performed through the air outlet port 5 in charging the refrigerant, the charging of the refrigerant becomes further smooth.
  • the plurality of sealing members 8 formed in, for example, a spherical shape are prepared, and as shown in FIG. 14D which shows the manufacturing method of the heat pipe 1 in sequence, the sealing members 8 are disposed on the refrigerant charging hole 4 and the air outlet port 5 .
  • the refrigerant charging hole 4 and the air outlet port 5 have the plurality of gas venting grooves 4 b formed around the inner periphery surface of the opening 4 a , so that even if the spherical sealing member 8 is disposed, the interior space 10 a of the cooling unit main body 10 is still communicated with the exterior space through the gas venting grooves 4 b as shown in FIG. 15B , thereby enabling gas venting from the interior space 10 a of the cooling unit main body 10 .
  • FIG. 14E which shows the manufacturing method of the heat pipe 1 in sequence
  • vacuum deaeration by pressure reduction is performed for, for example, 10 minutes through the gas venting grooves 4 b in this state under a normal temperature condition.
  • this step by performing the vacuum deaeration through the gas venting grooves 4 b , air in the interior space 10 a is removed through the gas venting grooves 4 b , harmful components are removed together with the air from the interior space 10 a , thereby reducing an outgas.
  • arrows in FIG. 14E represent the directions of the deaeration (gas venting).
  • a press 75 presses the sealing members 8 from the above for a couple of minutes in a normal temperature condition, and the sealing members 8 are subjected to low-temperature pressurization deformation.
  • the refrigerant charging hole 4 and the air outlet port 5 are tentatively sealed by the sealing members 8 .
  • the refrigerant charging hole 4 and the air outlet port 5 are plugged by the sealing members 8 .
  • the support structure Because the support structure is formed at portions opposite to the peripheral regions of the refrigerant charging hole 4 and the air outlet port 5 by causing the upper plate reinforcement member 50 , the intermediate plate reinforcement member 52 , the slit-provided reinforcement member 55 and the lower plate reinforcement member 60 to adhere tightly, the support structure receives external force from the press 75 when the sealing members 8 are pressed by the press 75 , so that the sealing members 8 can be surely pressurized by the external force from the press 75 without crushing the interior space 10 a.
  • the temperature at which vacuum deaeration is performed should be 25° C. or so.
  • the vacuum degree under a high temperature condition is set to, for example, 0.5 KPa for 10 minutes or so, and the press 75 presses the sealing members 8 from the above. Accordingly, the sealing members 8 are subjected to high-temperature pressurization deformation, deeply enter into the refrigerant charging hole 4 and the air outlet port 5 , so that the sealing members 8 are attached by pressure and further firmly plug the refrigerant charging hole 4 and the air outlet port 5 .
  • the sealing member 8 mainly performs plastic deformation by pressurization, and auxiliary performs plastic deformation by heating, and plugs the refrigerant charging hole 4 or the air outlet port 5 including the gas venting grooves 4 b . Therefore, as shown in FIGS. 15C and 16B , the sealing members 8 which have been in a spherical shape are formed in the shapes of the refrigerant charging hole and the air outlet port 5 by plastic deformation, attached to the refrigerant charging hole 4 and the air outlet port 5 by pressure, substantially become the sealing plugs, and seal the interior space 10 a of the cooling unit main body 10 . After the refrigerant charging hole 4 and the air outlet port 5 are plugged by the sealing members 8 , heating, vacuuming, and pressurization by the press 75 are terminated, thereby terminating pressurization, heating and vacuuming.
  • the outside surface of the sealing member 8 should form a flat plane with the outside surface of the cooling unit main body 10 . This is because that if the outside surface of the heat pipe 1 is flat, adherence of the heat pipe 1 to a radiator attached thereto like a fin becomes good, so that thermal conductivity therebetween is improved well.
  • the outside surface of the cooling unit main body 10 is subjected to nickel plating for anti-rusting. If the refrigerant charging hole 4 and the air outlet port 5 are plugged by the sealing members which are formed of solders, it is difficult to perform nickel plating well on the solders, and this raises a problem such that nickel plating is not performed well on those portions where the refrigerant charging hole 4 and the air outlet port 5 are plugged.
  • the refrigerant charging hole 4 and the air outlet port 5 are plugged by the sealing members 8 which are formed of the same copper-based metal as that of the cooling unit main body 10 , so that such a problem does not occur, and nickel plating can be performed well on those portions where the refrigerant charging hole 4 and the air outlet port 5 are plugged.
  • the plurality of heat pipes 1 may be laid out under a vacuum condition, the sealing members 8 may be disposed on the refrigerant charging hole 4 and the air outlet port 5 of each heat pipe 1 , gas venting, pressurization and heating of the sealing members 8 are performed on the plurality of heat pipes 1 at the same time, all of the sealing members 8 are undergone plastic deformation, thereby performing sealing on the plurality of heat pipes 1 at the same time.
  • the productivity of the heat pipe 1 can be improved in comparison with conventional sealing schemes that require time-consuming works, such as caulking, welding, and bonding which are separately performed for each refrigerant charging hole 4 , and such improvement of the productivity reduces the cost of the heat pipe 1 .
  • the interior space 10 a is set in a reduced pressure condition (e.g., 0.5 KPa or so when the refrigerant is water), the boiling point of the refrigerant drops, and the refrigerant becomes not likely to vaporize at a temperature (e.g., 30 to 35° C.) slightly higher than a normal temperature less than or equal to, for example, 50° C. Accordingly, the heat pipe 1 can cause the refrigerant to circulate successively and easily by slight heat from the cooling target device HE.
  • a reduced pressure condition e.g., 0.5 KPa or so when the refrigerant is water
  • the heat pipe 1 has the refrigerant charging hole 4 and the cooling unit main body 10 sealed by the sealing members 8 which are formed of the same plastic copper-based metal as that of the cooling unit main body 10 . Therefore, even if the refrigerant contacts both cooling unit main body 10 and sealing member 8 , or the cooling unit main body 10 and the sealing member 8 are exposed thereto, a local battery effect due to both cooling unit main body 10 and sealing member 8 does not occur, and as a result, it is possible to prevent corrosion inherent to the local battery effect, thereby making the heat pipe 1 further long-lived in comparison with the conventional ones by what corresponds to the prevention of corrosion.
  • the sealing effect can be enhanced under a high temperature condition of 200 to 300° C. or so.
  • the sealing member 8 When a solder is used as the sealing member 8 , the solder contains lead which is a harmful substance, and sealing with lead requires a maintenance or the like thus taking a cost, but according to the invention, a copper-based metal is used as the material of the sealing member 8 , the maintenance required for lead is unnecessary, thereby reducing the cost by what corresponds to it.
  • the cooling unit main body 10 should be formed of a copper-based metal, but when the cooling unit main body 10 is formed of a copper-based metal, the outside surface of the cooling unit main body 10 is normally subjected to nickel plating for anti-rusting.
  • the refrigerant charging hole 4 of the cooling unit main body 10 is plugged by a solder, the solder is eroded at the preparation for nickel plating, a plating film having weak adhesive force is formed on the surface of the solder, so that adhesion with the underlayer of a nickel plating film to be formed later becomes weak.
  • the cooling unit main body 10 is formed of a copper-based metal
  • the sealing member 8 for plugging the refrigerant charging hole 4 is also formed of a copper-based metal, so that it is possible to surely perform nickel plating well on the entire contour.
  • the spherical sealing members 8 are undergone plastic deformation in accordance with the shapes of the refrigerant charging hole 4 and the air outlet port 5 and serve as the sealing plugs. Therefore, the sealing members 8 are not likely to protrude from the top outside surface of the heat pipe 1 , and sealing does not detract the flatness of the outside surface of the heat pipe 1 , resulting in improvement of the degree of freedom of mounting the heat pipe 1 on a portable device or a compact device.
  • the heat pipe 1 when an electronic part, such as a CPU or an LED (Light Emitting Diode) which requires heat dissipation is mounted on one side and a radiator (heat dissipation device) like a fin is mounted on the other side, because the outside surface of the sealing member 8 does not protrude from the outside surface of the cooling unit main body 10 , adherence to the electronic part and the radiator are improved, thermal conductivity therebetween becomes well, thereby effectively dissipating heat generated by the electronic part or the like.
  • an electronic part such as a CPU or an LED (Light Emitting Diode) which requires heat dissipation is mounted on one side and a radiator (heat dissipation device) like a fin is mounted on the other side
  • the refrigerant charging hole 4 and the air outlet port 5 have the gas venting grooves 4 b provided around the inner periphery surface of the opening 4 a . Accordingly, when the sealing members 8 which become sealing plugs are mounted on the refrigerant charging hole 4 and the air outlet port 5 , and start melting so that sealing slightly progresses, the interior space 10 a of the heat pipe 1 is not plugged by the sealing members 8 on the refrigerant charging hole 4 and the air outlet port 5 , thereby ensuring gas venting.
  • the sealing member 8 is pressurized under a vacuum condition, the refrigerant charging hole 4 is tentatively sealed by the sealing member 8 , and the sealing member 8 is further pressurized and heated, so that the sealing member 8 formed of a plastic metal performs plastic deformation and deforms in accordance with the shape of the gas venting groove 4 b . Therefore, the sealing member 8 can surely plug the gas venting grooves 4 b , thereby preventing the refrigerant W charged in the interior space 10 a from leaking.
  • the upper plate reinforcement member 50 , the intermediate plate reinforcement member 52 , the slit-provided reinforcement member 55 , and the lower plate reinforcement member 60 adhere tightly to form the support structure at portions corresponding to the peripheral regions of the refrigerant charging hole 4 and the air outlet port 5 . Therefore, the mechanical strengths at the peripheral regions of the refrigerant charging hole 4 and the air outlet port 5 are improved, breakage such that the interior space 10 a is crushed by external force from the press 75 which is applied to the sealing member 8 from the outside of the upper plate 2 is prevented in a manufacturing process, and the productivity is improved, resulting in reduction of a production cost.
  • the vapor diffusion flow paths 44 and the capillary flow paths 42 are formed as the circulation path in the interior space 10 a .
  • the vapor diffusion flow paths 44 are formed in such a manner as to extend to the uttermost corners of the four sides from the center to cause heat to dissipate to the peripheral portion 12 of the cooing unit main body 10 and to perform heat dissipation efficiently.
  • the refrigerant charging hole 4 is disposed at one corner portion of the heat pipe 1 , and the air outlet port 5 is disposed at the other diagonal corner portion thereof.
  • the refrigerant charging hole 4 and the air outlet port 5 are disposed on the vapor diffusion flow paths 44 which employ a hollow structure. Therefore, when the sealing members 8 are disposed on the refrigerant charging hole 4 and the air outlet port 5 and a pressing process is performed, only the upper plate 2 receives external force from the press 75 if the regions opposite to the refrigerant charging hole 4 and the air outlet port 5 , respectively, merely employ a hollow structure, so that the upper plate 2 may be damaged.
  • the upper plate reinforcement member 50 , the intermediate plate reinforcement member 52 , the slit-provided reinforcement member 55 and the lower plate reinforcement member 60 adhere tightly to form the support structure in the vapor diffusion flow paths 44 which face the peripheral region of the refrigerant charging hole 4 or the air outlet port 5 . Accordingly, the support structure can receive external force from the press 75 , thereby preventing the upper plate 2 or the lower plate 3 from being damaged by the external force and the interior space 10 a from being crushed.
  • the upper plate reinforcement member 50 , the intermediate plate reinforcement member 52 , the slit-provided reinforcement member 55 and the lower plate reinforcement member 60 have the holes 53 , 57 for the refrigerant which are communicated with the refrigerant charging hole 4 and formed at a portion corresponding to the refrigerant charging hole 4 of the upper plate 2 . Accordingly, when the refrigerant W is charged in the interior space 10 a through the refrigerant charging hole 4 , the refrigerant W can spread evenly to all corners in the cooling unit main body 10 through the holes 53 , 57 , the slits 56 , and the like.
  • the slit-provided reinforcement member 55 has the slits 56 formed along the diffusion direction D of the refrigerant W which diffuse the vapor diffusion flow paths 44 , the refrigerant W is guided to the corner portion of the cooling unit main body 10 through the slits 56 , thereby enabling efficient heat dissipation.
  • the invention is not limited to the foregoing embodiment, and can be changed and modified in various forms.
  • a sealing member formed of a similar plastic metal to that of the cooling unit main body 10 may be used, and the same effects can be achieved in this case.
  • the cooling unit main body 10 may have no air outlet port.
  • the explanation and illustration thereof will be omitted.
  • the inkjet nozzle 80 makes a refrigerant (for example, pure water) into tiny refrigerant particles (water particle) W 2 each of which has a diameter of, for example, 50 to 300 ⁇ m, and successively charged one droplet by one droplet at a speed of approximately 1000 droplets per second.
  • the tiny refrigerant particles W 2 are regularly arranged in a line and supplied into the interior space 10 a of the cooling unit main body 10 .
  • the amount of a droplet is tiny, the effectiveness of charging of the refrigerant is extremely high because, for example, approximately 1000 droplets are successively charged per second at a fast speed.
  • FIGS. 18 and 19 are top plan views showing slit-provided reinforcement members 81 , 85 according to the other embodiment, and the difference from the slit-provided reinforcement member 55 is that the shape of the slit 56 differs.
  • a slit-provided reinforcement member 81 has slits 83 each formed in such a way that the width thereof gradually becomes wide from the center of a circular refrigerant hole 82 toward the outer periphery of the slit-provided reinforcement member 81 .
  • FIG. 18 shows that a slit-provided reinforcement member 81 has slits 83 each formed in such a way that the width thereof gradually becomes wide from the center of a circular refrigerant hole 82 toward the outer periphery of the slit-provided reinforcement member 81 .
  • a refrigerant charging hole 90 a or an air outlet port 90 b may be formed in a reversed trapezoidal conic structure such that the diameter thereof is largest at the upper end, and becomes gradually small toward the bottom end, and is smallest at the bottom end. As shown in FIG. 20A which shows the planer structure of a refrigerant charging hole or a air outlet port, and in FIG. 20B which shows the side sectional structure thereof, a refrigerant charging hole 90 a or an air outlet port 90 b may be formed in a reversed trapezoidal conic structure such that the diameter thereof is largest at the upper end, and becomes gradually small toward the bottom end, and is smallest at the bottom end. As shown in FIG.
  • FIG. 21C which shows the way of sealing by the sealing member 8
  • the sealing member 8 performs plastic deformation and completely fills out the lower portion 93
  • the residue of the sealing member 8 is retained in the upper portion 92 , so that it is possible to prevent the sealing member 8 from protruding from the top outside surface of the heat pipe 1 , and the top outside surface can be flat.
  • the same effect as that of the foregoing embodiment can be achieved in any embodiments shown in FIGS. 20A, 20B , and FIGS. 21A, 21B .

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JP5714836B2 (ja) * 2010-04-17 2015-05-07 モレックス インコーポレイテドＭｏｌｅｘ Ｉｎｃｏｒｐｏｒａｔｅｄ 熱輸送ユニット、電子基板、電子機器
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JP6121893B2 (ja) * 2013-12-24 2017-04-26 東芝ホームテクノ株式会社 シート型ヒートパイプ
JP6191561B2 (ja) * 2014-08-28 2017-09-06 東芝ホームテクノ株式会社 シート型ヒートパイプ
CN105764299B (zh) * 2014-12-19 2018-09-25 鹏鼎控股(深圳)股份有限公司 散热结构及其制作方法
CN104538836B (zh) * 2014-12-31 2018-02-02 西安炬光科技股份有限公司 一种用于高功率半导体激光器的液体制冷片
TWI612266B (zh) * 2016-06-28 2018-01-21 Cai Ming Kun 均溫裝置之腔體之製造方法及其結構
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TWI409424B (zh) 2013-09-21
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KR20090045146A (ko) 2009-05-07

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