JP4380209B2 - Manufacturing method of cooling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling device having a function of a heat pipe, an electronic device including the cooling device, and a method for manufacturing the cooling device.
[0002]
[Prior art]
Conventionally, a mechanism using a heat pipe has been proposed as a mechanism for cooling a heating element such as a CPU (Central Processing Unit) mounted on a circuit board such as a computer. The heat pipe encloses a condensable working fluid inside the container. Heat generated from the heating element is transmitted to the heat absorption part of the container of the heat pipe, and the working fluid is evaporated to become steam. When the working fluid becomes steam, the pressure in the vicinity of the heat input portion in the container increases, and therefore the pressure in the container flows to the low pressure side, that is, the heat radiating portion side. When the steam flows toward the heat radiating portion, the working fluid condenses and releases heat. The condensed working fluid returns to the heat input section through the wick provided in the container. The phenomenon in which the working fluid flows through the groove utilizes the capillary phenomenon. For example, a groove or a wire mesh formed on the inner surface of the container is a wick. In this way, the heat pipe cools the heat generating element by repeating heat absorption and heat dissipation (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2002-76664 A (FIG. 12 etc.)
[0004]
[Problems to be solved by the invention]
However, when manufacturing the heat pipe, it is necessary to fix the wick in contact with the inner wall of the container so that the thermal resistance with the container does not increase. In this case, there is a problem that the inner surface of the container is damaged when a wick formed of a wire mesh is used. When the inner surface of the container is damaged, dust is generated, and the dust remains in the container as it is, which may increase the heat resistance of the heat pipe. In addition, the wire mesh itself may be scraped off during the production to generate dust, which similarly causes an increase in thermal resistance.
[0005]
On the other hand, the structure of the wick using the groove is a structure in which a groove is formed directly on the inner wall of the container, so the thermal resistance is small, but the capillary force is inferior to that of the wick using a wire mesh. In addition, it is necessary to pay attention to the occurrence of burrs and cracks when grooving, and such burrs and cracks may become dust and heat resistance may increase.
[0006]
On the other hand, when the heat pipe container is made of metal like the heat dissipating device described in Patent Document 1, the heat conductivity is good, but there is a problem that it is not suitable for weight reduction. In the device described in Patent Document 1, the heat spreader or the like is thinned. However, since the thickness (thickness in the direction W) is still large, it is difficult to downsize the device. Therefore, for example, when the heat dissipation device is incorporated in a notebook computer, it is expected to achieve further miniaturization, thinning, and weight reduction.
[0007]
In view of the circumstances as described above, an object of the present invention is to provide a cooling device that can reduce heat resistance and the like and efficiently cool a heating element, an electronic device equipped with the cooling device, and a method of manufacturing the cooling device. There is.
[0008]
An object of the present invention is to provide a cooling device that can be reduced in size, thickness, or weight, an electronic device equipped with the cooling device, and a method of manufacturing the cooling device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a cooling device according to the present invention is provided in a container having an internal space and the internal space of the container, and evaporates and condenses by heat received from the outside of the container. And a cloth member that is provided in the internal space of the container and recirculates the condensed working fluid.
[0010]
In the present invention, the cloth member is used as the means for generating the capillary phenomenon. The cloth member has a finer mesh than a wire mesh conventionally used as a capillary tube. Accordingly, it is possible to provide a capillary force that is equal to or greater than the capillary force of the wire mesh, and there is no problem of generation of dust, for example, because the inner wall surface of the container is not damaged as in the prior art. can do. Further, since the cloth member can be made thinner than the wire mesh, the cooling device can be made smaller, thinner or lighter.
[0011]
In the present invention, the cloth member is a fiber and means a woven fabric, a knitted fabric, a non-woven fabric, or the like. Moreover, the cloth member may be provided in the whole interior space of the container. The shape of the container is preferably a flat plate shape. This is because it contributes to thinning.
[0012]
In one form of the present invention, the container has a first inner wall surface and a second inner wall surface facing the first inner wall surface, and the inner space of the container is at least the cloth member. A part has a first region formed continuously from the first inner wall surface to the second inner wall surface. In the present invention, since the cloth member is provided continuously from the first inner wall surface to the second inner wall surface, the conventional capillary tube provided along the inner wall surface of the container and having a hollow center is provided. In comparison, the capillary volume is increased. As a result, the flow rate of the recirculating working fluid is increased as compared with the conventional one, and the thermal efficiency can be improved.
[0013]
In an embodiment of the present invention, the internal space of the container further includes a second region that is a region other than the first region and through which the evaporated working fluid flows. In the present invention, the first region where the capillary force is improved is provided, and the second region which is the vapor path of the working fluid is provided. Thereby, since resistance when the evaporated working fluid flows can be reduced, thermal efficiency can be further improved.
[0014]
In one form of the present invention, the first region has a first end and a first other end, and the second region has a second end and a second other end, The internal space of the container has a loop shape with the second end connected to the first other end and the second other end connected to the first one end. In this way, the first region and the second region are combined to form a loop, whereby the evaporated working fluid and the condensed working fluid can be circulated in the same loop direction. Thereby, heat transport can be performed efficiently.
[0015]
In one form of this invention, it is a member for recirculating the condensed said working fluid, Comprising: The member whose heat conductivity is higher than the said cloth member is further comprised. In addition to the cloth member, by providing a member having a higher thermal conductivity than that of the cloth member, the thermal efficiency can be further increased and the cooling can be efficiently performed.
[0016]
For example, if a member having a higher thermal conductivity than the cloth member is knitted into the cloth member, the problem of damaging the inner wall surface of the container can be avoided as much as possible while increasing the thermal efficiency.
[0017]
Alternatively, the container has an inner wall surface, the cloth member is provided so as to cover at least a part of the inner wall surface, and the member having a higher thermal conductivity than the cloth member is at least a part of the surface of the cloth member. It is provided so as to cover. Thereby, the problem of damaging the inner wall surface of the container can be solved while increasing the thermal efficiency.
[0018]
An electronic device according to the present invention includes a container having an internal space, a working fluid that is provided in the internal space of the container, evaporates by heat received from the outside of the container, and releases heat by condensation, and the container And a cooling device provided with a cloth member that recirculates the condensed working fluid.
[0019]
In the present invention, the cloth member is used as the means for generating the capillary phenomenon. The cloth member has a finer mesh than a wire mesh conventionally used as a capillary tube. Therefore, it is possible to have a capillary force that is greater than the capillary force of the wire mesh, and it does not damage the inner wall surface of the container, for example, unlike conventional wire meshes. Can do. Further, since the cloth member can be made thinner than the wire mesh, the cooling device can be made smaller, thinner or lighter. As a result, the electronic device can be reduced in size, thickness, or weight. Examples of the electronic device include, but are not limited to, a computer and an AV device.
[0020]
The method for manufacturing a cooling device according to the present invention includes: (a) a working fluid having an action of evaporating and condensing by heat received from the outside of a container to recirculate the condensed working fluid. (B) impregnating the cloth member; and (b) attaching the cloth member to at least one inner wall surface of the first container member and the second container member constituting the part and the other part of the container; c) joining the first container member and the second container member.
[0021]
In the present invention, the cloth member is used as the means for generating the capillary phenomenon. The cloth member has a finer mesh than a wire mesh conventionally used as a capillary tube. Therefore, it is possible to have a capillary force that is greater than the capillary force of the wire mesh, and it does not damage the inner wall surface of the container, for example, unlike conventional wire meshes. Can do. Further, since the cloth member can be made thinner than the wire mesh, the cooling device can be made smaller, thinner or lighter.
[0022]
Another cooling device of the present invention includes a container having an internal space, a working fluid that is provided in the internal space of the container, evaporates by heat received from the outside of the container, and releases heat by condensation. And a fiber member that is provided in an internal space of the container and recirculates the condensed working fluid.
[0023]
The fiber member refers to a material having a ratio of length to thickness or diameter (aspect ratio) of 5: 1 or more. In this invention, it was set as the structure which uses a fiber member as a means to generate | occur | produce a capillary phenomenon. The fiber member has a finer mesh than a wire mesh conventionally used as a capillary tube. Therefore, it is possible to have a capillary force that is greater than the capillary force of the wire mesh, and it does not damage the inner wall surface of the container, for example, unlike conventional wire meshes. Can do. Further, since the fiber member can be made thinner than the metal mesh, the cooling device can be made smaller, thinner, or lighter.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
FIG. 1 is a perspective view showing a cooling device according to a first embodiment of the present invention. 2, 3 and 4 are an AA sectional view, a BB sectional view and a CC sectional view of the cooling device shown in FIG. 1, respectively. The cooling device 1 has a container 5. As shown in FIGS. 1 and 2, the container 5 has an opening 5 c at the center and has, for example, a loop shape. As shown in FIG. 4, a working fluid 6 is sealed in the internal space 2 of the container 5, and a cloth member 7 for generating a capillary phenomenon is provided. The container 5 is made of a material such as a metal or resin having a high thermal conductivity. Specific examples include metals such as copper and aluminum, and resins such as ABS and PPS. Moreover, you may use the resin material containing materials with high heat conductivity, such as a metal fiber, carbon, fullerenes, and a carbon nanotube. Thereby, thermal efficiency can be improved. As the working fluid 6, for example, pure water, methanol, ammonia, alternative chlorofluorocarbon, or the like can be used. The cloth member is a fiber and means a woven fabric, a knitted fabric, a non-woven fabric, or the like. Specific examples include chemical fibers such as nylon, polyester, and acrylic, but other fibers or synthetic fibers may be used.
[0026]
In the present embodiment, as shown in FIG. 3, a sheet member having a cloth member 7 with a thickness t of, for example, 0.4 mm is used. The thickness t is not limited to 0.4 mm and can be changed as appropriate. Further, a material having good thermal conductivity such as copper, aluminum, carbon fiber, etc. may be knitted into the cloth member 7. Thereby, thermal efficiency can further be improved.
[0027]
The cloth member generally has a finer mesh than a wire mesh conventionally used as a wick. Therefore, according to the cloth member, it is possible to have a capillary force that is greater than the capillary force of the wire mesh, and since the inner wall surfaces 5a and 5b of the container, for example, are not damaged as in the conventional case, dust or the like may be generated. The thermal resistance can be reduced. Further, since the cloth member 7 can be made thinner than the wire mesh, the cooling device 1 can be reduced in size, thickness, or weight.
[0028]
The cloth member 7 is provided in the first region 2a of the internal space 2 as shown in FIG. That is, the mainly condensed working fluid 6 flows through the first region 2a. On the other hand, the evaporated working fluid 6 circulates mainly due to the pressure difference in the second region 2b in the internal space 2 where the cloth member 7 is not provided. By setting it as such a structure, the heat receiving part 20 and the thermal radiation part 30 are formed. Therefore, when the cooling device 1 is mounted on an electronic device, for example, the heating element 3 is mounted so that the heating element 3 such as an integrated circuit chip is positioned in the vicinity of the heat receiving portion 20 as shown in FIG. A circuit board or the like (not shown) is installed.
[0029]
As shown in FIGS. 3 and 4, the cloth member 7 is continuously provided, for example, over the upper inner wall surface 5a of the container 5 and the lower inner wall surface 5b facing the upper inner wall surface 5a. That is, the cloth member 7 is provided in the entire internal space 2 in the first region 2a. As a result, as shown in FIG. 5, the volume of the capillary is increased compared to a conventional capillary that is provided along the inner wall surface 105 a of the container 105 and has a hollow center. As a result, in the present embodiment, the flow rate of the recirculating working fluid 6 is increased as compared with the conventional case, and the thermal efficiency can be increased. Here, the upper inner wall surface 5a and the lower inner wall surface 5b are referred to as an upper portion and a lower portion for convenience of explanation. That is, when the cooling device 1 is mounted on an electronic device, the upper inner wall surface 5a is not necessarily disposed above the electronic device, and the lower inner wall surface 5b is not disposed below the electronic device.
[0030]
Next, the operation of the cooling device 1 will be described. Heat generated from the heating element 3 is received from the heat receiving unit 20 of the cooling device 1. Specifically, the heat generated from the heating element 3 is transmitted to the surface of the container 5 in the heat receiving unit 20. When the working fluid 6 evaporates into steam due to the heat received by the heat receiving unit 20, the pressure in the container 5 near the heat receiving unit 20 increases, and therefore the pressure in the container 5 flows to the low side, that is, the heat radiating unit 30 side. (The direction of the arrow shown in FIG. 2). When the steam flows toward the heat radiating unit 30, the working fluid 6 is condensed and releases heat. The condensed working fluid 6 returns to the heat receiving part 20 side through the cloth member 7. In this way, the cooling device 1 cools the heating element 3 by repeating heat reception and heat dissipation.
[0031]
In the present embodiment, according to the cloth member, a capillary force greater than the capillary force of the wire mesh can be provided. Further, since the inner wall surfaces 5a and 5b of the container, for example, are not damaged as in the conventional case, there is no possibility that dust or the like is generated, and the thermal resistance can be reduced. Further, since the cloth member 7 can be made thinner than the wire mesh, the cooling device 1 can be reduced in size, thickness, or weight.
[0032]
In the present embodiment, the cloth member 7 with improved capillary force is provided in the first region 2a, and the second region 2b, which is the vapor path of the working fluid 6, is further provided. Thereby, since resistance when the evaporated working fluid flows can be reduced, thermal efficiency can be further improved. In particular, when the first region 2a and the second region 2b are combined to form a loop, the evaporated working fluid 6 and the condensed working fluid 6 can be circulated in the same loop direction. Thereby, heat transport can be performed efficiently.
[0033]
FIG. 6 is a diagram for explaining a method of manufacturing the cooling device 1. The container 5 has an upper container member 5A and a lower container member 5B as parts in advance. For example, first, the cloth member 7 is impregnated with the working fluid, and the cloth member 7 is attached to a predetermined position of the lower container member 5B, for example, the first region 2a. Alternatively, the cloth member 7 may be impregnated with the working fluid after the cloth member 7 is attached to the lower container member 5B. Then, the upper container member 5A and the lower container member 5B are joined. Specifically, for example, the upper end flat portions 5d and 5e of the lower container member 5B and the portions corresponding to the upper end flat portions of the upper container member 5A are brought into contact with each other, for example, heat welding, solder bonding, brazing, super Bonded by sonic bonding or the like. After joining, for example, the container 5 is sealed by reducing the pressure using a vacuum pump or the like through a hole for degassing or the like (not shown). Note that the cloth member 7 may be attached not only to the lower container member 5B but also to the upper container member 5A.
[0034]
FIG. 7 shows a modification of the cooling device 1 according to the first embodiment. The upper container member 25A and the lower container member 25B of the cooling device 21 are not formed in a loop shape on the appearance, but are formed in a flat plate shape. However, the internal space 22 of the container 25 is formed in a loop shape. As an example of a specific structure, for example, a mouth-shaped partition member may be provided on at least one inner wall surface of the upper container member 25A and the lower container member 25B.
[0035]
FIG. 8 is a sectional view of a cooling device according to the second embodiment of the present invention. In the present embodiment, for example, means for generating a capillary phenomenon provided in the internal space of the container 35 are the cloth member 37 and the member 38 having a higher thermal conductivity than the cloth member. Specifically, for example, the cloth member 37 is provided so as to cover the inner wall surface 35 a along the inner wall surface 35 a of the container 35. The member 38 is provided so as to cover the surface of the cloth member 37, that is, surrounded by the cloth member 37. The member 38 is made of, for example, copper or aluminum. By setting it as such a structure, the problem of damaging the inner wall surface 35a of the container 35 can be eliminated, improving the thermal efficiency of the cooling device 31. FIG.
[0036]
The cooling device 31 according to the second embodiment can have the same shape as the loop-shaped cooling device 1 shown in FIG. However, of course, it is not limited to a loop shape.
[0037]
FIG. 9 is a perspective view of a cooling device according to the third embodiment of the present invention. 10 is a cross-sectional view taken along the line DD shown in FIG.
[0038]
In the cooling device 11, for example, the cloth member 7 is provided in the internal space 12 of the long container 15 along the longitudinal direction, and a first region 12 a is formed. The cloth member 17 is designed and arranged in such a size that the steam path 12b as the second region can be formed on the side of the cloth member 7.
[0039]
Even with such a configuration, the cooling device 11 can have a capillary force that is greater than the capillary force of the conventional wire mesh. In addition, since the inner wall surface of the container is not damaged as in the prior art, there is no possibility that dust or the like is generated, and the thermal resistance can be reduced. Further, since the cloth member 17 can be made thinner than the wire mesh, the cooling device 11 can be reduced in size, thickness, or weight.
[0040]
FIG. 11 is a sectional view of a cooling device according to the fourth embodiment of the present invention.
[0041]
The container 45 of the cooling device 41 includes, for example, a flexible cover sheet 45A and a substrate 45B. The cooling device 41 includes a cloth member 47 sandwiched between a cover sheet 45A and a substrate 45B. Further, the cloth member 47 is designed and arranged in such a size that the steam passage 42b can be formed on the side of the cloth member 47.
[0042]
For example, a resin can be used as the material of the cover sheet 45A, and polyimide, polyamide, polyester, or the like can be used. For example, epoxy glass can be used for the substrate 45B. The thickness s of the cover sheet 45A can be set to, for example, about 0.1 mm. The thickness u of the substrate 45B can be about 0.1 mm. Since the thickness t of the cloth member 47 can be set to about 0.4 mm, for example, the total thickness of the cooling device 41 can be set to 1 mm or less. Since the cooling device 41 can be configured to be very thin as described above, it is possible to reduce the thickness, weight, and size, and to reduce the thickness, weight, and size of an electronic device on which the cooling device 41 is mounted. .
[0043]
The substrate 45B may also be a flexible resin sheet. Use of such a flexible cooling device 41 is very effective for a small electronic device. In particular, it is useful for small electronic devices equipped with a CPU or the like, small robots, small digital cameras, fuel cells, and the like that easily generate heat and consume power due to the generation of heat.
[0044]
Furthermore, by adopting a flexible structure, when the cooling device 41 is mounted on the electronic device, the number of installation locations is reduced, which contributes to the reduction in size and thickness of the electronic device.
[0045]
An example of the manufacturing method of the cooling device 41 according to the fourth embodiment will be described below.
[0046]
For example, the cloth member 47 impregnated with the working fluid 46 is attached to the substrate 45B, and the cover sheet 45A is pressure-bonded to the substrate 45B. Specifically, using a vacuum press or the like, pressure bonding is performed while maintaining the vapor path 42b. Further, the cooling device 41 can be configured by laminating and pressing the substrate 45B, the cloth member 47, and the cover sheet 45A while keeping the vapor path 42b in a vacuum filled with water vapor. Further, the substrate 45B, the cloth member 47, and the cover sheet 45A are pressure-bonded in advance, high pressure air is injected from one end, and the working fluid 46 is generated by cooling, whereby the cooling device 41 can be configured.
[0047]
FIG. 12 is a perspective view showing a cooling unit in which a fan motor or the like is attached to the cooling device according to the first to fourth embodiments described above.
[0048]
In this example, a motor unit 60 mounted with a fan motor 63 and a heat sink 65 are attached to the heat radiating part side of the container 55 of the cooling device 51, and a heat spreader 62 is attached to the heat receiving part side. The heat generating element 3 is installed on the heat spreader 62. The heat sink 65 is fixed to the cooling device 51 by, for example, burring press fitting, adhesion, caulking, or the like. The heat spreader 62 is also fixed to the cooling device 51 by adhesion or caulking.
[0049]
Although not shown, of course, at least a cloth member is provided inside the container 55 of the cooling device 51 as means for generating a capillary tube.
[0050]
The fan motor 63 is housed in the case 64. Air taken into the case 64 from the outside by the fan motor 63 flows to the heat sink 34 side through the opening 64a of the case.
[0051]
In the apparatus having such a configuration, the heat of the heat generating element 3 is diffused by the heat spreader 62, and the heat is received by the heat receiving portion of the cooling device 51. The cooling device 51 transports the heat to the heat radiating portion side, that is, to the heat sink 65. The heat sink 65 is cooled by the air flow supplied from the fan motor 63 and dissipates the transmitted heat.
[0052]
With such a cooling unit, the thermal efficiency can be further improved, and the heating element 3 can be efficiently cooled.
[0053]
The present invention is not limited to the embodiment described above, and various modifications are possible.
[0054]
The shape of the container of the cooling device is not limited to the shape described in the above embodiments, and may be, for example, a flat plate shape such as a triangle shape, an L shape, or a mouth shape. Moreover, the cross section of the container may have a substantially oval shape in which a circular shape is crushed, or is not limited to a flat plate shape, and a part of the surface of the container may be a curved surface shape.
[0055]
【The invention's effect】
As described above, according to the present invention, the heat resistance can be reduced and the heating element can be efficiently cooled. In addition, the cooling device and the electronic device can be reduced in size, thickness, or weight.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a cooling device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the cooling device shown in FIG.
FIG. 3 is a cross-sectional view of the cooling device shown in FIG. 1 taken along the line B-B.
4 is a cross-sectional view taken along the line CC of the cooling device shown in FIG.
FIG. 5 is a cross-sectional view showing a conventional cooling device.
FIG. 6 is a perspective view for explaining the manufacturing method of the cooling device according to the first embodiment.
FIG. 7 is a perspective view showing a modification of the cooling device 1 according to the first embodiment.
FIG. 8 is a cross-sectional view of a cooling device according to a second embodiment of the present invention.
FIG. 9 is a perspective view of a cooling device according to a third embodiment of the present invention.
10 is a DD cross-sectional view of the cooling device shown in FIG. 9;
FIG. 11 is a sectional view of a cooling device according to a fourth embodiment of the present invention.
FIG. 12 is a perspective view showing a cooling unit in which a fan motor is attached to the cooling device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11, 21, 31, 41, 51 ... Cooling device 2, 12, 22 ... Internal space 2a, 12a, ... 1st area | region 2b ... 2nd area | region 3 ... Heating element 5, 15, 25, 35, 45 55 ... Containers 5a, 5b, 25a, 25b, 35a ... Inner wall surfaces 5A, 25A ... Upper container members 5B, 25B ... Lower container members 6, 16, 36, 46 ... Working fluids 7, 17, 37, 47 ... Cloth members 38 ... Member 45A with higher thermal conductivity than cloth member ... Cover sheet 45B ... Substrate

Claims (2)

(A) impregnating a working fluid having a function of evaporating and condensing by heat received from outside the container into a cloth member for refluxing the condensed working fluid;
(B) Laminating the cloth member between the first container member and the second container member constituting a part and other parts of the container , and joining them under a reduced pressure condition in the presence of water vapor. The manufacturing method of the cooling device characterized by including these processes. (A) impregnating a working fluid having an action of evaporating and condensing by heat received from outside the container into a cloth member for refluxing the condensed working fluid;
  (B) a step of joining the cloth member so as to be sandwiched between a first container member and a second container member constituting a part and other parts of the container;
  (C) injecting high-pressure air from one end of the container in a joined state and cooling the container;
  The manufacturing method of the cooling device characterized by comprising.

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