HEAT TRANSPORTATION DEVICE PRODUCTION METHOD AND HEAT TRANSPORTATION DEVICE

Abstract

[Object] To provide a low-cost production method for a heat transportation device with which efficient production with a small number of steps is possible. [Solving Means] A capillary member (5) having a larger thickness than a frame member (2) is mounted on an inner surface (11) of a lower plate member (1). Subsequently, the frame member (2) is mounted on the inner surface (11) of the lower plate member (1), and an upper plate member (3) is mounted on the capillary member (5). Due to a difference between the thickness of the capillary member (5) and the thickness of the frame member (2), a squashing amount (G) is provided between the frame member (2) and the upper plate member (3). Then, the lower plate member (1) and the upper plate member (3) are diffusion-bonded with the frame member (2). At this time, the capillary member (5) is compressed by an amount corresponding to the squashing amount (G). Since the capillary member (5) has elasticity, a pressure (P) is partially absorbed, and a pressure (P′) smaller than the pressure (P) is applied to the lower plate member (1) from the capillary member (5). By the pressure (P′), the inner surface (11) of the lower plate member (1) and the capillary member (5) are diffusion-bonded.

Description

TECHNICAL FIELD

The present invention relates to a production method for a heat transportation device that transports heat using a phase change of a working fluid, and a heat transportation device.

BACKGROUND ART

For cooling electronic apparatuses such as a personal computer, cooling devices such as a heat pipe that transport heat generated from a heating portion of the electronic apparatus to a condensation portion to radiate it are being used.

In those cooling devices, vapor of a working fluid evaporated by heat generated at a high- temperature heating portion of the electronic apparatus moves to a low-temperature condensation portion to be condensed and radiated as heat. As a result, a cooling target is cooled.

In recent years, along with a miniaturization and thinning of electronic apparatuses, heat generation at an IC and the like provided inside the electronic apparatuses has become a large problem. Additional thinning of, for example, a flat-screen television is strongly demanded, and the problem on heat generation inside an electronic apparatus described above needs to be coped with to realize such thinning. As means for solving the problem, a compact, thin, and inexpensive cooling device is being demanded.

Patent Document 1 discloses a plurality of diffusion bonding steps including a diffusion bonding step 1 of attaching meshes to an upper cover and a lower cover constituting a heat spreader and a diffusion bonding step 2 of bonding the upper cover and the lower cover having the meshes and a reinforcing member. The plurality of diffusion bonding steps are each carried out under a favorable condition (paragraphs [0022]-[0027], [0032] , and [0033] , FIGS. 6A, 6B, 7, and 8 to 13).

Patent Document 1: 2006-140435

DISCLOSURE OF THE INVENTION

Problem to be solved by the Invention

However, when the plurality of diffusion bonding steps are carried out in other steps, time and costs required for producing the cooling device increases due to time and costs required for carrying out each of the diffusion bonding steps. As a result, efficient production of a cooling device and production of a cooling device at low costs become difficult.

In view of the circumstances as described above, an object of the present invention is to provide a low-cost production method for a heat transportation device by which efficient production with a small number of steps is possible, and a heat transportation device.

Means for solving the Problem

For attaining the above object, according to an embodiment of the present invention, there is provided a production method for a heat transportation device, including laminating a first plate and a second plate constituting a vessel of a heat transportation device that transports heat using a phase change of a working fluid and a capillary member that causes a capillary force to act on the working fluid such that the capillary member is interposed between the first plate and the second plate.

The first plate and the second plate are diffusion-bonded so that the first plate and the capillary member are diffusion-bonded.

For structuring the vessel of the heat transportation device, the first plate and the second plate are diffusion-bonded. In the diffusion bonding step, the first plate and the capillary member interposed between the first plate and the second plate are diffusion-bonded. Therefore, since the diffusion bonding is carried out a plurality of times in the same step, a low-cost production method for a heat transportation device by which efficient production with a small number of steps is possible is realized.

The capillary member may be formed of a material having elasticity. In this case, the diffusion bonding step may include diffusion-bonding the first plate and the second plate while compressing the capillary member.

The first plate and the second plate are diffusion-bonded by a high bonding force for enhancing sealing performance of the vessel. On the other hand, in the diffusion bonding step, the first plate and the capillary member are diffusion-bonded by an adequate pressure that causes an appropriate capillary force to act on the working fluid accommodated in the vessel. In other words, pressures required for the diffusion bonding differ in many cases. Since the capillary member has predetermined elasticity, the pressure applied at the time the first plate and the second plate are diffusion-bonded is partially absorbed by the capillary member. As a result, the first plate and the capillary member are diffusion-bonded with a pressure smaller than that applied at the time the first plate and the second plate are diffusion-bonded.

The capillary member may have a larger thickness than an internal space of the vessel constituted of the first plate and the second plate.

Accordingly, in the diffusion bonding step, the capillary member is positively compressed, and a part of the pressure applied at the time the first plate and the second plate are diffusion-bonded is positively absorbed.

The capillary member may include a first mesh layer and a second mesh layer that is laminated on the first mesh layer and constituted of coarser meshes than the first mesh layer.

The second plate may include a protrusion. In this case, the diffusion bonding step includes diffusion-bonding the first plate and the second plate while compressing the capillary member by the protrusion.

With the protrusion, it becomes possible to reinforce the internal space of the vessel and positively compress the capillary member.

The heat transportation device may include a frame member constituting side walls of the vessel. In this case, the diffusion bonding step includes diffusion-bonding the first plate and the second plate with the frame member so that the first plate and the capillary member are diffusion-bonded.

Based on a relationship between the thickness of the frame member constituting the side walls of the vessel and the thickness of the capillary member, a degree by which the capillary member is compressed and an amount of pressure to be absorbed by the capillary member are adjusted. Therefore, by appropriately setting the thickness of the frame member and the thickness of the capillary member, a desired pressure required for diffusion-bonding the first plate and the capillary member can be obtained.

The lamination step may include laminating a unit, that includes the first plate, the capillary member, and the second plate that are laminated with the capillary member being interposed between the first plate and the second plate, and a jig portion including a concave portion such that the unit is fit into the concave portion. In this case, the diffusion bonding step includes diffusion-bonding the first plate and the second plate of the unit by applying a pressure to the jig portion and the unit in a lamination direction.

By appropriately setting a depth of the concave portion of the jig portion and the thickness of the capillary member, the pressure required for diffusion-bonding the first plate and the capillary member in the diffusion bonding step can be obtained without variances.

The lamination step may include laminating a plurality of units each including the first plate, the capillary member, and the second plate and a plurality of jig portions such that each of the plurality of jig portions is inserted between the plurality of units. In this case, the diffusion bonding step includes diffusion-bonding the first plate and the second plate of each of the plurality of units by applying a pressure to the plurality of units and the plurality of jig portions in a lamination direction.

By applying a pressure to the plurality of units and the plurality of jig portions in the direction in which the plurality of units and the plurality of jig portions are laminated, a plurality of heat transportation devices are produced at the same time. As a result, a production time is shortened.

The capillary member may include a first member and a second member.

The first member has a first spring constant and is diffusion-bonded with the first plate.

The second member has a second spring constant larger than the first spring constant and is laminated on the first member.

Since the first member has a small spring constant and is apt to deform, the first member is positively compressed when the capillary member is compressed in the diffusion bonding step and is sufficiently diffusion-bonded with the first plate by that stress. Further, in the diffusion bonding step, variances of a deformation amount of the second member due to dimension tolerance are absorbed by the first member, for example. As a result, in the diffusion bonding step, a function of the capillary member that affects heat transportation performance is sufficiently exerted by the second member that has a large spring constant and is hardly deformed.

The diffusion bonding step may include diffusion-bonding the first plate and the second plate so that the first plate and the second plate are diffusion-bonded with the capillary member. In this case, the capillary member includes a third member having a third spring constant smaller than the second spring constant, the third member being laminated on the second member and being diffusion-bonded with the second plate.

By diffusion-bonding the capillary member with the first plate and the second plate, the internal space of the vessel of the heat transportation device is reinforced by the capillary member. At this time, by diffusion-bonding the third member having a small spring constant and the second plate, the capillary member and the second plate are diffusion-bonded sufficiently.

According to another embodiment of the present invention, there is provided a production method for a heat transportation device, including interposing, by bending a plate for constituting a vessel of a heat transportation device that transports heat using a phase change of a working fluid, a capillary member that causes a capillary force to act on the working fluid between a first portion and a second portion of the bent plate.

An end portion of the first portion and an end portion of the second portion are diffusion-bonded so that at least the first portion and the capillary member are diffusion-bonded, to thus form the vessel.

Accordingly, since the vessel is formed by bending a single plate, the number of components and costs can be reduced. Moreover, although, when constituting the vessel by a plurality of components, predetermined positioning accuracy of the components is required, high positioning accuracy as described above is not required in the present invention.

According to an embodiment of the present invention, there is provided a heat transportation device including a vessel including an inner surface, a working fluid, and a capillary member.

The working fluid is accommodated in the vessel and transports heat using a phase change.

The capillary member includes a first member and a second member and causes a capillary force to act on the working fluid.

The first member has a first spring constant and is diffusion-bonded with the inner surface.

The second member has a second spring constant larger than the first spring constant and is laminated on the first member.

According to another embodiment of the present invention, there is provided a heat transportation device including a vessel including side walls, a working fluid, and a capillary member.

The vessel includes a frame member constituting the side walls, and a first plate and a second plate bonded to the frame member such that the frame member is interposed between the first plate and the second plate.

The working fluid transports heat inside the vessel using a phase change.

The capillary member causes a capillary force to act on the working fluid.

In the heat transportation device, the vessel can be structured with components having simple structures. Moreover, since a volume of the internal space of the vessel is determined based on the thickness of the frame member, by appropriately setting the thickness of the frame member, the volume of the internal space can be set with ease.

EFFECT OF THE INVENTION

As described above, according to the present invention, a low-cost production method for a heat transportation device by which efficient production with a small number of steps is possible and a heat transportation device can be realized.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A schematic cross-sectional diagram showing a heat transportation device produced by a production method for a heat transportation device according to a first embodiment.

FIG. 2 An exploded perspective view schematically showing the heat transportation device produced by the production method for a heat transportation device according to the first embodiment.

FIG. 3 A diagram for explaining the production method for a heat transportation device according to the first embodiment.

FIGS. 4 Schematic cross-sectional diagrams sequentially showing the production method for a heat transportation device according to the first embodiment.

FIG. 5 A table showing a squashing amount and a leak percent defective of the heat transportation device produced with the corresponding squashing amount.

FIGS. 6 Diagrams obtained by observing an inner surface of a lower plate member of the heat transportation device produced in the first embodiment.

FIGS. 7 Schematic cross-sectional diagrams sequentially showing a production method for a heat transportation device according to a second embodiment.

FIG. 8 A schematic cross-sectional diagram showing a heat transportation device produced by a production method for a heat transportation device according to a third embodiment.

FIG. 9 A diagram obtained by observing an inner surface of a lower plate member of the heat transportation device produced in the third embodiment.

FIG. 10 A diagram for explaining the production method for a heat transportation device that uses a jig.

FIGS. 11 Schematic cross-sectional diagrams sequentially showing a production method for a heat transportation device according to a fourth embodiment.

FIGS. 12 Schematic cross-sectional diagrams sequentially showing a production method for a heat transportation device according to a fifth embodiment.

FIG. 13 A cross-sectional diagram showing a heat transportation device in which a heat source is provided on a side close to a vapor phase side.

FIG. 14 A perspective view showing a heat transportation device according to a sixth embodiment.

FIG. 15 A cross-sectional diagram taken along the line A-A of FIG. 14.

FIG. 16 A development diagram of a plate member constituting a vessel of the heat transportation device according to the sixth embodiment.

FIGS. 17 Diagrams showing a production method for a heat transportation device according to the sixth embodiment.

FIG. 18 A development diagram of a plate member for explaining a heat transportation device according to a modified example.

FIG. 19 A perspective view showing a heat transportation device according to a seventh embodiment.

FIG. 20 A cross-sectional diagram taken along the line A-A of FIG. 19.

FIG. 21 A development diagram of a plate member constituting a vessel of the heat transportation device according to the seventh embodiment.

FIG. 22 A diagram for explaining a production method for a heat transportation device according to an eighth embodiment.

FIG. 23 A schematic graph showing a relationship between a stress applied to each mesh member and a deformation amount (squashed amount) caused by the stress.

FIGS. 24 Schematic cross-sectional diagrams sequentially showing the production method for a heat transportation device according to the eighth embodiment.

FIGS. 25 Enlarged diagrams of an upper plate member, a bonding mesh member, and a second mesh member shown in FIGS. 24.

FIGS. 26 Enlarged diagrams showing a state where a capillary member and the upper plate member are diffusion bonded as a comparative example.

FIGS. 27 Schematic diagrams showing mesh members that are weaved differently using metal thin lines.

FIG. 28 A diagram showing a modified example of the capillary member shown in FIG. 22.

FIG. 29 A diagram for explaining a heat transportation device according to a ninth embodiment.

FIG. 30 An enlarged plan view of an inlet and an injection path shown in FIG. 29.

FIG. 31 A diagram for explaining a heat transportation device according to a tenth embodiment.

BEST MODES FOR CARRYING OUT THE INVENTION

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

First embodiment

(Structure of heat transportation device)

FIG. 1 is a schematic cross-sectional diagram showing a heat transportation device produced by a production method for a heat transportation device according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view thereof. The cross-sectional diagram of FIG. 1 is a cross-sectional diagram of a heat transportation device 100 in a longitudinal direction. In descriptions below, directions of the cross-sectional diagrams are the same.

The heat transportation device 100 includes a vessel 4 and a capillary member 5 provided inside the vessel 4. The vessel 4 is constituted of a lower plate member 1, a frame member 2, and an upper plate member 3. The frame member 2 constitutes side walls of the vessel 4. Inside the vessel 4, a working fluid (not shown) that transports heat using a phase change is sealed and the capillary member 5 that causes a capillary force to act on the working fluid is formed. The capillary member 5 includes a first mesh layer 6 and a second mesh layer 7 laminated on the first mesh layer 6. The second mesh layer 7 is constituted of rougher meshes than the first mesh layer 6.

As the working fluid, pure water, ethanol, and the like are used.

Copper is typically used as a material of the lower plate member 1, the frame member 2, and the upper plate member 3 constituting the vessel 4. In addition, nickel, aluminum, and stainless steel, for example, may be used. Thicknesses of the lower plate member 1 and the upper plate member 3 are typically 0.1 mm to 0.8 mm. A width a of the frame member 2 is typically 2 mm.

The thickness of the frame member 2 is, as will be described later, set as appropriate based on a relationship with a thickness of the capillary member 5. Here, the materials, numerical values, and the like that are presented as typical examples are not particularly limited. The same holds true hereinafter.

As shown in FIG. 2, the first mesh layer 6 and the second mesh layer 7 are formed by laminating one or a plurality of mesh members 8 having net-like meshes formed by metal thin lines. A thickness of each mesh member 8 is typically 0.02 mm to 0.05 mm.

Layers other than the mesh layer may be used as the capillary member 5, the example of which is a bundle of a plurality of wires. Any kind of layer may be used as long as it can cause a capillary force to act on the working fluid and has predetermined elasticity. In this embodiment, 2 to 5 mesh members 8 are laminated as the first mesh layer 6, and one mesh member 8 is laminated on the first mesh layer 6 as the second mesh layer 7. The plurality of mesh members 8 are laminated by, for example, brazing, bonding using an adhesive, and plating processing.

When the heat transportation device 100 is not operating, the working fluid is mainly drawn to the first mesh layer 6 having a strong capillary force out of the first mesh layer 6 and the second mesh layer 7 to be held.

(Operation of heat transportation device)

An operation of the heat transportation device 100 will be described. In an endothermic portion V (see FIG. 1) of the heat transportation device 100, heat generated from a heat source 9 such as a circuit device causes the working fluid in a liquid phase to evaporate. The working fluid in a vapor phase moves inside the vessel 4 to a heat radiation portion W, radiates heat in the heat radiation portion W, and is condensed. The working fluid changed to the liquid phase in the heat radiation portion W moves inside the vessel 4 to the endothermic portion V, receives heat from the heat source 9, and is again caused to evaporate. By repeating such a cycle, the heat source 9 is cooled. In the heat transportation device 100 of this embodiment, the working fluid in the vapor phase moves mainly through the second mesh layer 7. Further, the working fluid in the liquid phase moves by a capillary force generated by the first mesh layer 6.

It should be noted that FIG. 1 shows an example where the heat source 9 is provided on a side close to the liquid phase side of the heat transportation device 100, that is, a side close to the first mesh layer 6. However, since the heat transportation device 100 is formed as a thin plate, high heat transportation performance can be exerted even when the heat source 9 is provided on a side close to the vapor phase side of the heat transportation device 100, that is, a side close to the second mesh layer 7.

(Production method for a heat transportation device 100)

FIG. 3 is a diagram for explaining the production method for the heat transportation device 100. Here, the thickness of the capillary member 5 constituted of the first mesh layer 6 and the second mesh layer 7 laminated on the first mesh layer 6 is represented by t₁. In addition, a thickness of an internal space of the vessel 4 structured by diffusion-bonding the lower plate member 1 and the upper plate member 3 with the frame member 2, that is, a thickness of the frame member 2 is represented by t₂. As shown in FIG. 3, the thickness t₁ of the capillary member 5 is larger than the thickness t₂ of the frame member 2. A difference between the thickness t₁ of the capillary member 5 and the thickness t₂ of the frame member 2 is typically 0 mm to 0.2 mm.

FIGS. 4 are schematic cross-sectional diagrams sequentially showing the production method for the heat transportation device 100.

As shown in FIG. 4(A), a surface of the lower plate member 1 on the internal space side of the vessel 4 is an inner surface 11 of the lower plate member 1. The capillary member 5 is mounted on the inner surface 11.

As shown in FIG. 4(B), the frame member 2 is mounted on the inner surface 11 of the lower plate member 1, and the upper plate member 3 is mounted on the capillary member 5. In other words, the lower plate member 1, the capillary member 5, and the upper plate member 3 are laminated so as to interpose the capillary member 5 between the lower plate member 1 and the upper plate member 3.

As described above, the thickness t₁ of the capillary member 5 is larger than the thickness t₂ of the frame member 2. Therefore, as shown in FIG. 4(B), since the upper plate member 3 is mounted on the capillary member 5, a gap is formed between the upper plate member 3 and the frame member 2. A surface of the upper plate member 3 on the internal space side of the vessel 4 is an inner surface 31 of the upper plate member 3, and a surface of the frame member 2 opposed to the upper plate member 3 is an opposing surface 21. Moreover, a gap formed between the inner surface 31 of the upper plate member 3 and the opposing surface 21 of the frame member 2 is represented by G.

In this embodiment, the difference between the thickness t₁ of the capillary member 5 and the thickness t₂ of the frame member 2 is 0 mm to 0.2 mm. Thus, the gap G between the inner surface 31 of the upper plate member 3 and the opposing surface 21 of the frame member 2 is within the range of 0 mm to 0.2 mm. Since the upper plate member 3 and the frame member 2 are diffusion-bonded, the gap G is squashed depending on a pressure required for the diffusion bonding. Hereinafter, the gap G will be referred to as squashing amount G.

As shown in FIG. 4(C), a pressure P is applied from the upper plate member 3 side, with the result that the lower plate member 1 and the upper plate member 3 are diffusion-bonded with the frame member 2. At this time, the capillary member 5 is compressed by an amount corresponding to the squashing amount G. Since the capillary member 5 has elasticity, the pressure P is partially absorbed, and a pressure P′ smaller than the pressure P is applied to the lower plate member 1 from the capillary member 5. By the pressure P′, the inner surface 11 of the lower plate member 1 and the capillary member 5 are diffusion-bonded.

For example, for preventing a leak defect in which a small hole or the like breaks airtightness of the vessel 4, the lower plate member 1 and the upper plate member 3 are diffusion-bonded with the frame member 2 with a high bonding force (pressure P). The lower plate member 1 and the first mesh layer 6 are diffusion-bonded by an adequate pressure (pressure P′) with which a capillary force appropriately acts on the working fluid.

Further, by a reaction of the pressure P′, the upper plate member 3 is also applied with a pressure P″ smaller than the pressure P by the compressed capillary member 5. By the pressure P″, the inner surface 31 of the upper plate member 3 and the capillary member 5 are diffusion-bonded. In this embodiment, although the pressure P is applied from the upper plate member 3 side, the pressure P may be applied from the lower plate member 1 side instead.

When the squashing amount G is 0 mm, the difference between the thickness t₁ of the capillary member 5 and the thickness t₂ of the frame member 2 becomes 0 mm, and t₁ =t₂ is thus established. However, even when the squashing amount G is 0 mm, the upper plate member 3 mounted on the capillary member 5 in FIG. 4(B) is mounted on the capillary member 5 and the frame member 2. Since the diffusion bonding step of FIG. 4(C) is carried out under high temperature, a temperature of the upper plate member 3 also becomes high, and the upper plate member 3 is thus deformed. Due to the deformation, the capillary member 5 is compressed.

FIG. 5 is a table showing the squashing amount G and a leak percent defective of the heat transportation device 100 produced with the squashing amount G. As shown in the table of FIG. 5, a leak percent defective of 0% was confirmed with the squashing amount G within the range of, for example, 0 mm to 0.10 mm.

FIG. 6(A) is an observation photograph of the inner surface 11 of the lower plate member 1 of the heat transportation device 100 produced with the squashing amount G being set to 0.10 mm. FIG. 6(B) also shows the inner surface 11 of the lower plate member 1 of the heat transportation device 100 produced with the squashing amount G being set to 0 mm.

FIGS. 6(A) and 6(B) both show dents (circled Ks) arranged almost at regular intervals on the inner surface 11 of the lower plate member 1. The dents are made by diffusion-bonding the inner surface 11 of the lower plate member 1 and the first mesh layer 6. In other words, it can be seen that the inner surface 11 of the lower plate member 1 and the first mesh layer 6 are positively diffusion-bonded in the diffusion bonding step of FIG. 4(C) with the squashing amount G being set within the range of 0 mm to 0.10 mm.

As described above, by the production method for the heat transportation device 100 of this embodiment, the lower plate member 1 and the upper plate member 3 are diffusion-bonded with the frame member 2 for structuring the vessel 4 of the heat transportation device 100. In the diffusion bonding step, the lower plate member 1 and the capillary member 5 laminated so as to be interposed between the lower plate member 1 and the upper plate member 3 are diffusion-bonded. Therefore, since the diffusion bonding is carried out a plurality of times in the same step, a low-cost production method for a heat transportation device with which an efficient production with a small number of steps is possible is realized.

In a case where the diffusion bonding is carried out a plurality of times in other steps, the heat transportation device is exposed to a high-temperature state every time the diffusion bonding is carried out. This causes lowering of a yield in producing a heat transportation device. For example, after the inner surface 11 of the lower plate member 1 and the capillary member 5 are diffusion-bonded (diffusion bonding a), the vessel 4 is formed by diffusion-bonding the lower plate member 1 and the upper plate member 3 with the frame member 2 in another step (diffusion bonding β). In this case, since the lower plate member 1, the frame member 2, and the upper plate member 3 are once exposed to high temperature in the diffusion bonding a, defects in which small holes appear in the vessel 4 formed in the diffusion bonding β occur frequently. However, by the production method for the heat transportation device 100 of this embodiment, it is possible to prevent the yield as described above from lowering and suppress costs.

Further, a compression degree of the capillary member 5 is adjusted based on the relationship between the thickness t₂ of the frame member 2 constituting the side walls of the vessel 4 and the thickness t₁ of the capillary member 5, and a part of the pressure P to be absorbed by the capillary member 5 is adjusted. Therefore, by appropriately setting the thickness t₂ of the frame member 2 and the thickness t₁ of the capillary member 5, a desired pressure P′ required for diffusion-bonding the inner surface 11 of the lower plate member 1 and the capillary member 5 can be obtained.

Second embodiment

A second embodiment of the present invention will be described. In descriptions below, descriptions on structures and operations that are the same as those of the production method for the heat transportation device 100 described in the first embodiment will be omitted or simplified.

(Structure of heat transportation device)

FIGS. 7 are schematic cross-sectional diagrams sequentially showing a production method for a heat transportation device according to the second embodiment of the present invention. A heat transportation device 200 includes, in place of the upper plate member 3 and the frame member 2 of the heat transportation device 100 of the first embodiment, an upper plate member 203. The upper plate member 203 and the lower plate member 1 constitute a vessel 204 of the heat transportation device 200.

The upper plate member 203 has a vessel shape and includes an upper plate portion 203a that is mounted on the capillary member 5, a side wall portion 203b constituting side walls of the vessel 204, and a bonding portion 203c that is diffusion-bonded with the lower plate member 1.

When a height of the side wall portion 203b seen from an internal space side of the vessel 204 (hereinafter, referred to as height of side wall portion 203b) is represented by t₃, a thickness of the internal space of the vessel 204 is represented by t₃. Comparing the height t₃ of the side wall portion 203b and the thickness t₁ of the capillary member 5, the thickness t₁ of the capillary member 5 is larger than the height t₃ of the side wall portion 203b.

(Production method for a heat transportation device 200)

As shown in FIG. 7(A), the capillary member 5 is mounted on the inner surface 11 of the lower plate member 1.

As shown in FIG. 7(B), the upper plate member 203 is mounted on the capillary member 5. Since the thickness t₁ of the capillary member 5 is larger than the height t₃ of the side wall portion 203b, the upper plate member 203 is mounted on the capillary member 5, with the result that a gap is formed between the upper plate member 203 and the lower plate member 1. A surface of the bonding portion 203c of the upper plate member 203 that is opposed to the lower plate member 1 is an opposing surface 231, and a gap formed between the opposing surface 231 and the inner surface 11 of the lower plate member 1 is set as a squashing amount G.

As shown in FIG. 7(C), a pressure P is applied from the upper plate member 203 side so that the lower plate member 1 and the upper plate member 203 are diffusion-bonded. At this time, the capillary member 5 is compressed by an amount corresponding to the squashing amount G, and a part of the pressure P is absorbed. A pressure P′ smaller than the pressure P is applied to the lower plate member 1 from the capillary member 5, and the inner surface 11 of the lower plate member 1 and the capillary member 5 are diffusion-bonded by the pressure P′.

As described above, by appropriately setting the height t₃ of the side wall portion 203b and the thickness t₁ of the capillary member 5, the production method for the heat transportation device 200 of this embodiment bears the same effect as the production method for the heat transportation device 100 according to the first embodiment. Moreover, by producing the upper plate member 203 using, for example, press processing and die machining such as cast processing, costs required for producing the heat transportation device 200 can be suppressed. Moreover, due to the bonding portion 203c of the upper plate member 203, a sufficient bonding area of the upper plate member 203 and the lower plate member 1 can be obtained. As a result, airtightness of the vessel 204 that is formed by diffusion-bonding the upper plate member 203 and the lower plate member 1 can be enhanced.

Third embodiment

FIG. 8 is a schematic cross-sectional diagram showing a heat transportation device produced by a production method for a heat transportation device according to a third embodiment. The cross-sectional diagram of FIG. 8 is a cross-sectional diagram of a heat transportation device 300 in the short-side direction. Further, in descriptions below, the illustration of the capillary member 5 is simplified.

The heat transportation device 300 includes an upper plate member 303 in place of the upper plate member 203 of the heat transportation device 200 according to the second embodiment. The upper plate member 303 and the lower plate member 1 constitute a vessel 304 of the heat transportation device 300.

The upper plate member 303 includes, similar to the upper plate member 203 of the heat transportation device 200 according to the second embodiment, an upper plate portion 303a, a side wall portion 303b, and a bonding portion 303c. The upper plate member 303 is different from the upper plate member 203 in that the upper plate portion 303a includes protrusions 313.

The protrusions 313 protrude toward the internal space of the vessel 304 of the heat transportation device 300. The protrusions 313 are elongated in the longitudinal direction of the heat transportation device 300 and provided on the upper plate portion 303a of the upper plate member 303.

During production of the heat transportation device 300 of this embodiment, the upper plate member 303 and the lower plate member 1 are diffusion-bonded while the capillary member 5 is compressed and squashed by the protrusions 313. In addition, the capillary member 5 and the lower plate member 1 are diffusion-bonded in this diffusion bonding step.

FIG. 9 is an observation photograph of the inner surface 11 of the lower plate member 1 of the heat transportation device 300 produced in this embodiment.

The capillary member 5 is compressed by the protrusions 313. Dents (circled Ks) formed by the diffusion bonding of the inner surface 11 of the lower plate member 1 and the capillary member 5 appear around an area on the inner surface 11 of the lower plate member 1 corresponding to the compressed portion (area circled by broken line). In this embodiment, the protrusions 313 are provided at two positions along the longitudinal direction of the heat transportation device 300. As shown in FIG. 9, two dents arranged almost at regular intervals can be confirmed on the inner surface 11 (L1 and L2).

As described above, since the upper plate member 303 includes the protrusions 313 in the heat transportation device 300 of this embodiment, it is possible to reinforce the internal space of the vessel 304 and positively compress the capillary member 5 by the protrusions 313. Also by the protrusions 313, the capillary member 5 can be compressed even when the thickness t₁ of the capillary member 5 is smaller than the thickness of the internal space of the vessel 304. For example, desired design as in providing the capillary member 5 in a flow path of a working fluid in a liquid phase but not in a flow path of a working fluid in a vapor phase becomes possible (see FIG. 8).

Further, the protrusions 313 can be formed by die machining or an etching technique such as RIE (Reactive Ion Etching), and costs required for producing the heat transportation device 300 can be suppressed.

Though the protrusions 313 are elongated in the longitudinal direction of the heat transportation device 300 in this embodiment, the present invention is not limited thereto. It is also possible to provide a desired number of protrusions at desired positions on the upper plate portion 303a. As a result, it becomes possible to realize an effect that, for example, a volume of the flow path of the working fluid in the vapor phase increases and a heat transportation efficiency of the heat transportation device 300 becomes higher.

Fourth embodiment

FIG. 10 is a diagram for explaining the production method for a heat transportation device that uses a jig.

A heat transportation device 400 has almost the same structure as the heat transportation device 200 according to the second embodiment. The heat transportation device 400 is structurally different from the heat transportation device 200 in that a side wall portion 403b of an upper plate member 403 having a vessel shape is tilted with respect to a thickness direction of a vessel 404. In this embodiment, an upper plate portion 403a, the side wall portion 403b, and a bonding portion 403c of the upper plate member 403 have almost the same thickness.

The upper plate member 403, the lower plate member 1, and the capillary member 5 interposed between the upper plate member 403 and the lower plate member 1 constitute a heat transportation device unit 450.

A jig portion 600 includes a mounting surface 610 on which the upper plate member 403 of the heat transportation device unit 450 is mounted. The mounting surface 610 of the jig portion 600 includes a lower surface 610a on which the upper plate portion 403a of the upper plate member 403 is mounted and an upper surface 610b on which the bonding portion 403c is mounted. The lower surface 610a and the upper surface 610b are connected by a step, and the step, the lower surface 610a, and the upper surface 610b form a concave portion of the jig portion 600.

A height from the lower surface 610a to the upper surface 610b, which is a depth of the concave portion of the jig portion 600, is represented by t₄. Comparing the height t₄ and the thickness t₁ of the capillary member 5, the thickness t₁ of the capillary member 5 is larger by 0 mm to 0.2 mm.

Carbon or stainless steel is typically used as a material of the jig portion 600.

(Production method for heat transportation device 400)

FIGS. 11 are schematic cross-sectional diagrams sequentially showing a production method for the heat transportation device 400.

As shown in FIG. 11(A), the upper plate member 403, the capillary member 5, and the lower plate member 1 are sequentially laminated on the mounting surface 610 of the jig portion 600. A squashing amount G is provided between the bonding portion 403c of the upper plate member 403 and the lower plate member 1. The squashing amount G is a difference between a sum of the height t₄ and a thickness of the bonding portion 403c (height X) and a sum of the thickness t₁ of the capillary member 5 and a thickness of the upper plate portion 403a (height Y).

In this embodiment, the upper plate portion 403a and the bonding portion 403c have almost the same thickness. Therefore, the squashing amount G becomes almost the same as the difference between the height t₄ and the thickness t₁ of the capillary member 5.

As shown in FIG. 11(B), a pressure P required for diffusion-bonding the upper plate member 403 and the lower plate member 1 constituting the heat transportation device unit 450 is applied in a direction in which the heat transportation device unit 450 and the jig portion 600 are laminated. At this time, by a pressure P″ applied to the lower plate member 1 from the capillary member 5 having elasticity, the inner surface 11 of the lower plate member 1 and the capillary member 5 are diffusion-bonded.

For example, when the upper plate member 403 is formed plurally by die machining, heights of the side wall portions 403b of the plurality of upper plate members 403 may not be the same and variances may be caused due to errors caused during formation.

However, in this embodiment, the bonding portion 403c of the upper plate member 403 is diffusion-bonded with the lower plate member 1 while being pressed by the upper surface 610b of the jig portion 600. Therefore, irrespective of the variances in heights of the side wall portions 403b, the squashing amount G is determined based on the difference between the height t₄ and the thickness t₁ of the capillary member 5. Accordingly, since the capillary members 5 are compressed by an amount corresponding to the squashing amount G without variances in the diffusion bonding step shown in FIG. 11(B), pressures P″ required for diffusion-bonding the lower plate members 1 and the capillary members 5 can be obtained without variances.

In this embodiment, the upper plate portion 403a and bonding portion 403c of the upper plate member 403 have almost the same thickness, though not limited thereto. The height t₄ and the thickness t₁ of the capillary member 5 can be set as appropriate based on the shape of the upper plate member 403 so that a desired squashing amount G can be provided.

Fifth embodiment

FIGS. 12 are schematic cross-sectional diagrams sequentially showing a production method for a heat transportation device that uses a plurality of jigs. Jig portions 700 and a heat transportation device 500 have almost the same structure as the jig portion 600 and the heat transportation device 400 according to the fourth embodiment.

As shown in FIG. 12(A), an upper plate member 503, the capillary member 5, and the lower plate member 1 are sequentially laminated on a mounting surface 710 of the jig portion 700. Further, the jig portion 700 is laminated on the lower plate member 1, and the upper plate member 503, the capillary member 5, and the lower plate member 1 are sequentially laminated on the mounting surface 710 of the jig portion 700. A plurality of heat transportation device units 550 and a plurality of jig portions 700 are laminated as described above. A squashing amount G is provided between a bonding portion 503c of the upper plate member 503 and the lower plate member 1 in each of the heat transportation device units 550.

As shown in FIG. 12(B), a pressure P required for diffusion-bonding the upper plate member 503 and the lower plate member 1 constituting the heat transportation device unit 550 is applied in a direction in which the plurality of heat transportation device units 550 and the plurality of jig portion 700 are laminated. At this time, by a pressure P″ applied to the lower plate member 1 from the capillary member 5 having elasticity, the inner surface 11 of the lower plate member 1 and the capillary member 5 are diffusion-bonded.

By thus applying the pressure P to the plurality of heat transportation device units 550 and the plurality of jig portions 700 in the direction in which the plurality of heat transportation device units 550 and the plurality of jig portions 700 are laminated in the production method for the heat transportation device 500 of this embodiment, the plurality of heat transportation devices 500 are produced at the same time. In other words, batch processing becomes possible in the production of the heat transportation device 500.

Since the diffusion bonding is carried out with a large load in a vacuum environment, costs required for a single diffusion bonding is high. Moreover, since the diffusion bonding step includes a process of cooling the heat transportation device under the vacuum environment after the vessel of the heat transportation device is bonded at high temperature, it takes a large amount of time. However, since the batch processing described above becomes possible according to the production method for the heat transportation device 500 of this embodiment, costs can be suppressed, and a production time can be shortened. As a result, an additionally-efficient low-cost production method for a heat transportation device is realized.

Sixth embodiment

Next, a sixth embodiment of the present invention will be described.

In the above embodiments, the vessel has been constituted of the upper plate member, the lower plate member, and the like. On the other hand, in the sixth embodiment, the vessel is formed by bending a single plate member. Therefore, that point will mainly be described.

FIG. 14 is a perspective view showing a heat transportation device according to a sixth embodiment. FIG. 15 is a cross-sectional diagram taken along the line A-A of FIG. 14. FIG. 16 is a development diagram of a plate member constituting a vessel of the heat transportation device.

As shown in FIG. 14, a heat transportation device 110 includes a vessel 51 having a shape of a rectangular thin plate that is elongated in one direction (Y-axis direction). The vessel 51 is formed by bending a single plate member 52.

The plate member 52 is typically formed of oxygen-free copper, tough pitch copper, or a copper alloy. However, the material is not limited thereto, and the plate member 52 may be formed of metal other than copper, or a material having high heat conductivity may be used.

As shown in FIGS. 14 and 15, the vessel 51 has a shape in which a side portion 51c elongated in a longitudinal direction (Y-axis direction) is bent. Specifically, the vessel 51 has a shape in which the side portion 51c is bent since the plate member 52 shown in FIG. 16 is bent at substantially the center of the plate member 52. In descriptions below, the side portion 51c may be referred to as bent portion 51c.

The vessel 51 includes a bonding portion 53 at a side portion 51d on the other side of the side portion 51c (bent portion 51c) and side portions 51e and 51f provided along the short-side direction. The bonding portion 53 protrudes from the side portions 51d, 51e, and 51f. The bent plate member 52 is bonded at the bonding portion 53. The bonding portion 53 corresponds to a bonding area 52a (hatched area) of the plate member 52 shown in FIG. 16. The bonding area 52a is an area within a predetermined distance d from an end portion 52b of the plate member 52.

The capillary member 5 is provided inside the vessel 51. The capillary member 5 includes one or a plurality of mesh members 8 as described above. The thickness of the capillary member 5 can be set to be about the same as the thickness of the internal space of the vessel 51 (may be slightly larger or smaller than thickness of internal space).

(Production method for heat transportation device 110)

FIGS. 17 are diagrams showing the production method for a heat transportation device.

As shown in FIG. 17(A), the plate member 52 is prepared first. Then, the plate member 52 is bent at substantially the center thereof.

After the plate member 52 is bent a predetermined angle, the capillary member 5 is inserted between the bent plate member 52 as shown in FIG. 17(B). It should be noted that the capillary member 5 may be set at a predetermined position on the plate member 52 before the plate member 52 is started to be bent.

After the capillary member 5 is inserted between the bent plate member 52, the plate member 52 is additionally bent so as to sandwich the capillary member 5 as shown in FIG. 17(C). Then, the bonding portion 53 (bonding area 52a) of the bent plate member 52 is bonded by diffusion bonding, with the result that the capillary member 5 is diffusion-bonded with an upper plate portion 52c and lower plate portion 52d of the plate member 52.

In the case of the heat transportation device 110, since the vessel 51 is formed by a single plate member 52, the number of components and costs can be reduced. Moreover, when the vessel 51 is formed by two or more members, there is a need to position those members. However, in this embodiment, positioning of the members is unnecessary. Therefore, the heat transportation device 110 can be produced with ease.

Modified Example

FIG. 18 is a development diagram of the plate member for explaining the heat transportation device 110 according to a modified example.

As shown in FIG. 18, the plate member 52 includes a groove 54 formed at the center of the plate member 52 in the longitudinal direction (Y-axis direction). The groove 54 is formed by, for example, press processing or etching processing, though the method of forming the groove 54 is not particularly limited.

By providing the groove 54 in the plate member 52, it becomes easy to bend the plate member 52. Accordingly, the heat transportation device 110 can be produced more easily. It should be noted that although the plate member 52 is bent in the longitudinal direction (with Y direction as axis), it may also be bent in the short-side direction (with X direction as axis).

Seventh embodiment

Next, a seventh embodiment of the present invention will be described. It should be noted that points different from those of the sixth embodiment will be described in the seventh embodiment.

FIG. 19 is a perspective view showing a heat transportation device according to the seventh embodiment. FIG. 20 is a cross-sectional diagram taken along the line A-A of FIG. 19. FIG. 21 is a development diagram of a plate member constituting a vessel of the heat transportation device.

As shown in FIGS. 19 and 20, a heat transportation device 120 includes a vessel 61 having a shape of a rectangular thin plate elongated in one direction (Y-axis direction).

The vessel 61 is formed by bending a plate member 62 shown in FIG. 21 at the center. The plate member 62 has two openings 65 formed at the center of the plate member 62 along the longitudinal direction of the plate member 62. By thus providing the openings 65, the left-hand side plate and right-hand side plate of the plate member 62 are connected by three areas 66.

The vessel 61 includes a bonding portion 63 at side portions 61c and 61d in a direction along the longitudinal direction (Y-axis direction) and side portions 61e and 61f in a direction along the short- side direction (X-axis direction). The upper plate and the lower plate are diffusion-bonded at the bonding portion 63 to thus constitute the vessel 61. The bonding portion 63 corresponds to bonding areas 62a and 62b as hatched areas of the plate member 62 shown in FIG. 21.

As a result of the bonding of the upper plate and the lower plate as described above, three protrusions 64 protruding from the side portion 61c are formed.

Since the openings 65 are provided on the plate member 62 in the heat transportation device 120, the plate member 62 can be bent with ease. As a result, the heat transportation device 120 can be produced more easily.

A groove formed by, for example, press processing may be formed in an area 66 between the opening 65 and an edge portion 62c and an area 66 between the two openings 65. As a result, the plate member 62 can be bent more easily.

Eighth embodiment

(Structure of heat transportation device)

FIG. 22 is a diagram for explaining a production method for a heat transportation device according to an eighth embodiment of the present invention. A heat transportation device 800 of this embodiment includes, in place of the capillary member 5 of the heat transportation device 200 according to the second embodiment, a capillary member 805 having a thickness t₁.

The capillary member 805 includes a first mesh member 860, a second mesh member 870 laminated on the first mesh member 860, and a bonding mesh member 850 laminated on the second mesh member 870. In the heat transportation device 800 of this embodiment, the working fluid in the vapor phase moves mainly through the first mesh member 860, and the working fluid in the liquid phase moves mainly through the second mesh member 870.

Comparing a spring constant of the second mesh member 870 and a spring constant of the bonding mesh member 850, the spring constant of the second mesh member 870 is larger. A spring constant of the first mesh member 860 is also set to be larger than the spring constant of the bonding mesh member 850. The spring constant of the first mesh member 860 and the spring constant of the second mesh member 870 may either be the same or different. However, when the spring constants of the first mesh member 860 and the second mesh member 870 differ, the difference is smaller than a difference between the spring constants of the second mesh member 870 and the bonding mesh member 850. In this embodiment, the spring constants of the first mesh member 860 and the second mesh member 870 are almost the same.

Here, the spring constants will be described. The spring constant described in this embodiment refers to a spring constant of each mesh member in a thickness direction. FIG. 23 is a schematic graph showing a relationship between a stress and a deformation amount (squashed amount) in the thickness direction caused by the stress at the time the stress is applied to the bonding mesh member 850, the first mesh member 860, and the second mesh member 870 in the thickness direction.

In the graph shown in FIG. 23, the relationship between the stress and deformation amount of the bonding mesh member 850 having a small spring constant is indicated by a broken line. On the other hand, the relationship between the stress and deformation amount of the first mesh member 860 and the second mesh member 870 having a large spring constant is indicated by a solid line. As indicated by “difference in deformation amount” in the graph, when the same stress σ is applied to the bonding mesh member 850, the first mesh member 860, and the second mesh member 870, the deformation amount of the bonding mesh member 850 is the largest. In other words, the bonding mesh member 850 having a small spring constant is more apt to deform than the first mesh member 860 and the second mesh member 870 having a large spring constant.

The spring constant and the shape of the mesh members will be described. In a case where, in mesh members formed by weaving a plurality of metal thin lines, sizes of meshes of the woven metal thin lines are the same, the spring constant of the mesh member having thicker (diameter) metal thin lines is larger. When the diameters of the metal thin lines are the same, the mesh member having smaller meshes has a larger spring constant. By thus appropriately setting the sizes and diameters of the metal thin lines to be woven, mesh members having desired spring constants can be obtained. Alternatively, it is also possible to appropriately set the spring constants of the mesh members by appropriately setting a material of the metal thin lines to be used and the like.

In this embodiment, the size of the meshes of the metal thin lines in the bonding mesh member 850 having a small spring constant is smaller than that of the meshes of the metal thin lines to be woven as the first mesh member 860 and the second mesh member 870. However, in the bonding mesh member 850, metal thin lines having a smaller diameter than those used for the first mesh member 860 and the second mesh member 870 are used. As a result, the spring constant of the bonding mesh member 850 is set to be smaller than those of the first mesh member 860 and the second mesh member 870.

(Production method for heat transportation device 800)

As shown in FIG. 24(A), the first mesh member 860 of the capillary member 805 is mounted on the inner surface 11 of the lower plate member 1. Further, the upper plate member 203 is mounted on the bonding mesh member 850 of the capillary member 805. A squashing amount G is provided between the lower plate member 1 and the upper plate member 203.

As shown in FIG. 24(B), the pressure P is applied from the upper plate member 203 side so that the lower plate member 1 and the upper plate member 203 are diffusion-bonded. At this time, by the pressures P′ and P″ from the capillary member 805 compressed by an amount corresponding to the squashing amount G, the capillary member 805, the lower plate member 1, and the upper plate member 203 are diffusion-bonded.

The diffusion bonding of the capillary member 805 and the upper plate member 203 in the diffusion bonding step shown in FIG. 24(B) will be described. FIGS. 25 are enlarged diagrams of the upper plate member 203, the bonding mesh member 850, and the second mesh member 870 shown in FIGS. 24. FIGS. 26 are enlarged diagrams showing a state where a capillary member 895 taken as a comparative example and the upper plate member 203 are diffusion bonded. In the capillary member 895, the bonding mesh member 850 is not laminated on the second mesh member 870. Therefore, FIGS. 26 show enlarged diagrams of the upper plate member 203 and the second mesh member 870. In descriptions below, the second mesh member 870 of the capillary member 895 will be referred to as second mesh member 870′.

FIGS. 25 show a plurality of metal thin lines 855 that are woven as the bonding mesh member 850 and a plurality of metal thin lines 875 (875a and 875b) that are woven as the second mesh member 870. The metal thin lines 855 and the metal thin lines 875 are woven in the X direction shown in FIGS. 25. FIGS. 26 also show a plurality of metal thin lines 875′ (875a′ and 875b′) that are woven as the second mesh member 870′. In FIGS. 25 and 26, metal thin lines that are woven with the metal thin lines 855, 875, and 875′ in a direction different from the X direction are omitted.

FIG. 25(A) shows the bonding mesh member 850 and the second mesh member 870 before being diffusion-bonded with the upper plate member 203. As shown in FIG. 25(A), the woven metal thin lines 855 and 875 vary at positions in the thickness direction of the heat transportation device 800 (Z direction in FIGS. 25) due to dimension tolerance. Similarly, the metal thin lines 875′ of the second mesh member 870′ vary due to dimension tolerance.

When the second mesh member 870′ having variances is diffusion-bonded with the upper plate member 203, the metal thin lines 875a′ are diffusion-bonded with the upper plate member 203, but the metal thin lines 875b′ are not diffusion-bonded with the upper plate member 203 as shown in FIG. 26(A). In this state, it cannot be said that the capillary member 895 and the upper plate member 203 are sufficiently diffusion-bonded.

When increasing the pressure in the diffusion bonding step for diffusion-bonding the metal thin lines 875b′ with the upper plate member 203, the metal thin lines 875a′ are largely deformed as compared to the metal thin lines 875b′ as shown in FIG. 26(B). When such a difference in the deformation amounts of the metal thin lines 875a′ and 875b′ is caused, the function on performance of the heat transportation device that causes a capillary force to act on the working fluid in the liquid phase may not be fully exerted.

On the other hand, when the capillary member 805 of this embodiment including the bonding mesh member 850 is diffusion-bonded with the upper plate member 203, the bonding mesh member 850 and the second mesh member 870 are diffusion-bonded with the upper plate member 203 as shown in FIG. 25(B). The bonding mesh member 850 having a small spring constant is sufficiently deformed in the diffusion bonding step and sufficiently diffusion-bonded with the upper plate member 203. In the second mesh member 870 that is hard to be deformed due to its large spring constant, the metal thin lines 875a are diffusion-bonded with the upper plate member 203. The metal thin lines 875b are not diffusion-bonded with the upper plate member 203, but are diffusion-bonded with the metal thin lines 855.

As described above, in this embodiment, the bonding mesh member 850 having a small spring constant is sufficiently compressed in the diffusion bonding step to be sufficiently diffusion-bonded with the upper plate member 203 by that stress. Moreover, variances of the deformation amount of the second mesh member 870 due to dimension tolerance can be absorbed by the bonding mesh member 850. Therefore, it becomes possible to prevent the metal thin lines 875a diffusion-bonded with the upper plate member 203 to be largely deformed as compared to the metal thin lines 875b as shown in FIG. 25(B). As a result, the second mesh member 870 is sufficiently bonded with the upper plate member 203, and the function on the heat transportation performance described above can be fully exerted. For example, the effect of this embodiment becomes large when the heat transportation device 800 is to handle a high heat flux density.

In this embodiment, the dimension tolerance of the second mesh member 870 has been described. However, variances in the deformation amount of the second mesh member 870 may be caused due to variances in the thickness of the upper plate member 203, the height of the side wall portion 203b (t₃ shown in FIG. 22), and the like. Also in those cases, the variances in the deformation amount of the second mesh member 870 can be absorbed by the bonding mesh member 850.

FIGS. 27(A) and 27(B) are schematic diagrams showing mesh members that are formed by differently weaving the metal thin lines. FIGS. 27(A) and 27(B) respectively show mesh members M and N that are formed by weaving the same metal thin lines in the same mesh size. The mesh member M shown in FIG. 27(A) is formed such that a thickness m thereof becomes almost 3 times the diameter r of the metal thin lines. The mesh member n shown in FIG. 27(B) is formed such that a thickness n thereof becomes almost twice the diameter r of the metal thin lines. Specifically, since the mesh member N is weaved tighter than the mesh member M in the thickness direction of the mesh members (direction shown in FIGS. 27), the mesh member N has a larger spring constant than the mesh member M. The spring constants may be set as appropriate based on the way the metal thin lines are weaved as described above.

The capillary member 805 of this embodiment is obtained by laminating mesh members. However, the capillary member may take any form as long as it can cause a capillary force to act on the working fluid and has predetermined elasticity as described in the first embodiment. As such a capillary member, in addition to that described above, there are a blind-like or lattice-like member formed by, for example, an etching technique, a member in which grooves are formed, and the like. Alternatively, a member having a sinter structure of metallic powders may be used as the capillary member. In this case, by providing a member that has a small spring constant and is apt to deform on the upper plate member side of the capillary member, the same effect as this embodiment can be obtained. Furthermore, those described above can be used as the capillary member in every embodiment of the present invention.

Modified Example

FIG. 28 is a diagram showing a modified example of the capillary member 805. The capillary member 805 is obtained by laminating a bonding mesh member 840 on the other side of the first mesh member 860 on which the second mesh member 870 is laminated. The spring constant of the bonding mesh member 840 is smaller than that of the first mesh member 860. In other words, the bonding mesh member 840 is more apt to deform than the first mesh member 860.

By diffusion-bonding the capillary member 805 with the upper plate member 203 and the lower plate member 1, the internal space of the vessel 204 of the heat transportation device 800 is reinforced. At this time, by diffusion-bonding the bonding mesh member 840 laminated on the first mesh member 860 with the lower plate member 1, the capillary member 805 and the lower plate member 1 are sufficiently diffusion-bonded to each other.

The first mesh member 860 is a mesh member that becomes a flow path of the working fluid in the vapor phase. Therefore, if the first mesh member 860 is largely deformed in the diffusion bonding step, a flow path resistance generated at the time the working fluid in the vapor phase moves may become large. Moreover, if the first mesh member 860 is largely deformed, a pressure loss caused at the time the working fluid circulates inside the vessel 204 of the heat transportation device 800 may become large. However, by using the first mesh member 860 that has a large spring constant and is hard to be deformed, the above problem can be prevented from occurring.

Ninth embodiment

FIG. 29 is a diagram for explaining a heat transportation device according to a ninth embodiment of the present invention. A heat transportation device 900 of this embodiment is obtained by forming an inlet 900a and an injection flow path 900b described below on the inner surface 11 of the lower plate member 1 in the heat transportation device 100 of the first embodiment.

The inlet 900a and the injection flow path 900b are formed for injecting the working fluid in the vessel 4 in the production process of the heat transportation device 900. The inlet 900a and the injection flow path 900b are formed at an end portion of the lower plate member 1 in the longitudinal direction (X direction shown in FIG. 29) in an area where the lower plate member 1 is diffusion-bonded with the frame member 2 on the inner surface 11.

FIG. 30 is an enlarged plan view of the inlet 900a and the injection flow path 900b. The inlet 900a penetrates the lower plate member 1. The injection flow path 900b is a groove formed on the inner surface 1 so as be in communication with the inlet 900a and is in communication with the inside of the vessel 4 at an end portion thereof on the other side of the side on which the inlet 900a is provided. As shown in FIG. 30, the injection flow path 900b is formed in an L shape, for example.

The injection flow path 900b only needs to be formed by, for example, end mill processing, laser processing, press processing, or microfabrication such as photolithography and half etching used in producing semiconductors. Press processing has characteristics that no burr appears. Laser processing and end mill processing require no mold, and grooves of any shape can be formed.

The inlet 900a and the injection flow path 900b are sealed by, for example, swage processing after the working fluid is injected into the vessel 4 in the production process of the heat transportation device 900.

Tenth embodiment

FIG. 30 is a diagram for explaining a heat transportation device according to a tenth embodiment of the present invention. In the heat transportation device 900 shown in FIG. 29, the inlet 900a and the injection flow path 900b are formed on the lower plate member 1. In a heat transportation device 910 of this embodiment, an inlet 910a is formed on the upper plate member 3, and a groove to be an injection flow path 910b is formed on the frame member 2 as shown in FIG. 30.

The inlet 910a is formed at an end portion of the upper plate member 3 in the longitudinal direction (X direction shown in FIG. 30) while penetrating the upper plate member 3. The injection flow path 910b is formed in an area where the frame member 2 is diffusion-bonded with the upper plate member 3. The injection flow path 910b is in communication with the inlet 910a, and an end portion of the injection flow path 910b on the other side of the side that is in communication with the inlet 910a is in communication with the inside of the vessel 4. Although the inlet 910a is formed on the upper plate member 3 in this embodiment, it is also possible to form the inlet 910a on the lower plate member 1 and form the injection flow path 910b in an area the frame member 2 is diffusion-bonded with the lower plate member 1.

If the injection flow path 910b is formed on the frame member 2 by press processing, the surface of the frame member 2 on the other side of the side on which the injection flow path 910b is formed becomes bumpy. In this case, the frame member 2 cannot be diffusion-bonded with the lower plate member 1. Therefore, in the case of this embodiment, the injection flow path 910b only needs to be formed by laser processing or end mill processing.

In the above embodiments, wire discharge processing (wire cut) may be used for processing or cutting the upper plate member, the lower plate member, the frame member, or the capillary member. The wire discharge processing is a processing method for processing a member, that involves applying a voltage to a wire formed of, for example, brass, tungsten, and molybdenum, and generating an electrical discharge between a member to be processed and the wire. By using the wire discharge processing, highly-accurate microfabrication is realized. In addition, a processing time of the members can be shortened.

The present invention is not limited to the above embodiments and can be variously modified without departing from the gist of the present invention.

For example, the batch processing described in the fifth embodiment may be used in the production method for a heat transportation device according to the first, second, third, and fourth embodiments. By changing the shape of the jig portion 700 used in the fifth embodiment to a shape that corresponds to the lower plate member and the upper plate member, the batch processing can be used in other embodiments.

Description of Symbols

1 lower plate member

2 frame member

3, 203, 303, 403, 503 upper plate member

4, 51, 61, 204, 304, 404 vessel

5, 805 capillary member

6 first mesh layer

7 second mesh layer

8 mesh member

9 heat source

11 inner surface of lower plate member

21 opposing surface of side wall portion

31 inner surface of upper plate member

52, 62 plate member

100, 110, 120, 200, 300, 400, 500, 800, 900, 910 heat transportation device

203a, 303a, 403a upper plate portion

203b, 303b, 403b side wall portion

203c, 303c, 403c, 503c bonding portion

231 opposing surface of bonding portion

313 protrusion

450, 550 heat transportation device unit

600, 700 jig portion

610, 710 mounting surface

610a lower surface

610b upper surface

840, 850 bonding mesh member

860 first mesh member

870 second mesh member

900a, 910a inlet

900b, 910b injection flow path

Claims

1. A production method for a heat transportation device, comprising the steps of:

laminating a first plate and a second plate constituting a vessel of a heat transportation device that transports heat using a phase change of a working fluid and a capillary member that causes a capillary force to act on the working fluid such that the capillary member is interposed between the first plate and the second plate; and

diffusion-bonding the first plate and the second plate so that the first plate and the capillary member are diffusion-bonded.

2. The production method for a heat transportation device according to claim 1,

wherein the capillary member has a larger thickness than an internal space of the vessel constituted of the first plate and the second plate.

3. The production method for a heat transportation device according to claim 1 or 2,

wherein the capillary member is formed of a material having elasticity, and

wherein the diffusion bonding step includes diffusion-bonding the first plate and the second plate while compressing the capillary member.

4. The production method for a heat transportation device according to claim 3,

wherein the capillary member includes a first mesh layer and a second mesh layer that is laminated on the first mesh layer and constituted of coarser meshes than the first mesh layer.

5. The production method for a heat transportation device according to claim 3,

wherein the second plate includes a protrusion, and

wherein the diffusion bonding step includes diffusion-bonding the first plate and the second plate while compressing the capillary member by the protrusion.

6. The production method for a heat transportation device according to claim 1,

wherein the heat transportation device includes a frame member constituting side walls of the vessel, and

wherein the diffusion bonding step includes diffusion-bonding the first plate and the second plate with the frame member so that the first plate and the capillary member are diffusion-bonded.

7. The production method for a heat transportation device according to claim 1,

wherein the lamination step includes laminating a unit, that includes the first plate, the capillary member, and the second plate that are laminated with the capillary member being interposed between the first plate and the second plate, and a jig portion including a concave portion such that the unit is fit into the concave portion, and

wherein the diffusion bonding step includes diffusion-bonding the first plate and the second plate of the unit by applying a pressure to the jig portion and the unit in a lamination direction.

8. The production method for a heat transportation device according to claim 1,

wherein the lamination step includes laminating a plurality of units each including the first plate, the capillary member, and the second plate and a plurality of jig portions such that each of the plurality of jig portions is inserted between the plurality of units, and

wherein the diffusion bonding step includes diffusion-bonding the first plate and the second plate of each of the plurality of units by applying a pressure to the plurality of units and the plurality of jig portions in a lamination direction.

9. The production method for a heat transportation device according to claim 3,

wherein the capillary member includes a first member that has a first spring constant and is diffusion-bonded with the first plate, and a second member that has a second spring constant larger than the first spring constant and is laminated on the first member.

10. The production method for a heat transportation device according to claim 9,

wherein the diffusion bonding step includes diffusion-bonding the first plate and the second plate so that the first plate and the second plate are diffusion-bonded with the capillary member, and wherein the capillary member includes a third member having a third spring constant smaller than the second spring constant, the third member being laminated on the second member and being diffusion- bonded with the second plate.

11. A production method for a heat transportation device, comprising:

interposing, by bending a plate for constituting a vessel of a heat transportation device that transports heat using a phase change of a working fluid, a capillary member that causes a capillary force to act on the working fluid between a first portion and a second portion of the bent plate; and

diffusion-bonding an end portion of the first portion and an end portion of the second portion so that the first portion and the capillary member are diffusion-bonded, to thus form the vessel.

12. A heat transportation device, comprising:

a vessel including an inner surface;

a working fluid that is accommodated in the vessel and transports heat using a phase change; and

a capillary member including a first member that has a first spring constant and is diffusion-bonded with the inner surface and a second member that has a second spring constant larger than the first spring constant and is laminated on the first member, the capillary member causing a capillary force to act on the working fluid.

13. A heat transportation device, comprising:

a vessel including side walls, a frame member constituting the side walls, and a first plate and a second plate bonded to the frame member such that the frame member is interposed between the first plate and the second plate;

a working fluid that transports heat inside the vessel using a phase change; and

a capillary member that causes a capillary force to act on the working fluid.