JP5902404B2 - Flat heat pipe and method of manufacturing the same - Google Patents

Description

  The present invention relates to a heat pipe configured to transport heat by a working fluid enclosed in a container, and in particular, a wick for generating a capillary force for returning the working fluid to an evaporation unit is formed by a thin wire and powder. The present invention relates to a heat pipe that is configured and has a flat shape as a whole, and a method for manufacturing the heat pipe.

  A heat pipe basically encloses a fluid that evaporates and condenses in a target temperature range, such as water or alcohol, as a working fluid inside a container (container) from which non-condensable gas such as air has been deaerated. Further, a wick for generating a capillary force for refluxing the liquid phase working fluid is provided inside the container. Therefore, in the heat pipe, the working fluid receives heat from the outside and evaporates, and the vapor flows toward a low pressure portion and then dissipates heat and condenses. As a result, the working fluid transports heat by its latent heat. The condensed working fluid penetrates into the wick. On the other hand, since the capillary force due to the wick is generated at the location where evaporation occurs, the working fluid that has permeated the wick is returned to the location where evaporation occurs due to the capillary force.

  As described above, in the heat pipe, a vapor flow is generated between the evaporation portion where heat is transferred from the outside and the heat dissipation portion where the working fluid radiates heat to the outside, and a liquid flow is generated in the opposite direction. As a result, heat is transported. Therefore, in order to improve the heat transport capability or reduce the thermal resistance, it is preferable to generate the vapor flow and the liquid flow smoothly and sufficiently. In addition, there are various uses for heat pipes. For example, heat pipes may be used for cooling in electronic devices. In such cases, heat pipes are also reduced in size and weight as electronic devices and circuits become smaller. It is desirable.

  Thus, various techniques for securing a flow path for a vapor flow, improving the reflux characteristics of the working fluid, and further reducing the size have been developed. In this Patent Document 1, a core material having a notch is inserted into a pipe, a metal powder is filled in a space formed by the inner wall surface and the notch of the pipe, and this is heated. Forms a wick sintered with metal powder and fixes it to the inner wall surface of the pipe, then pulls out only the core material from the pipe, and then the wick faces the inner wall surface fixing the wick. A flat heat pipe is described which is flattened by crushing the pipe so as to be in contact with other inner wall surfaces. Therefore, in the flat heat pipe described in Patent Document 1, capillary force is generated between the wick and the other inner wall surface, that is, a reflux path is formed between them, and the working fluid can be circulated. It is said that heat transport can be strengthened.

JP 2011-43320 A

  When configured as described in Patent Document 1, the vapor space is divided into two in the state where the inner wall surface of the flattened container, that is, the other inner wall surface and the wick obtained by sintering the metal powder are in contact with each other. Two narrow vapor spaces will result. Therefore, the steam space cannot be effectively used, for example, the flow velocity of the working fluid vapor is increased in the narrow steam space, and the heat transport capability may be reduced. In addition, the wick made of sintered metal powder does not form a continuous flow path for the working fluid, so the flow resistance of the working fluid increases. As a result, the flat fluid heat pipe improves the flow characteristics of the working fluid. This may be disadvantageous. Furthermore, in the configuration described in Patent Document 1, since the pipe is crushed so that the other inner wall surface and the wick are in contact with each other, the working fluid can be vaporized at those contact portions. Therefore, the evaporation area of the working fluid in the wick may be reduced accordingly.

  The present invention has been made paying attention to the technical problem described above, and provides a flat heat pipe having a wick with improved reflux characteristics and a manufacturing method thereof without reducing the evaporation area of the working fluid in the wick. It is intended to provide.

In order to achieve the above object , the present invention provides a flat heat pipe that transports heat by a working fluid that is heated to evaporate and dissipates heat to condense. A container and a wick formed by mixing a large number of fine wires and powder, and the wick is sintered in a raised state on one flat surface inside the container over the entire length of the container The evaporated working fluid is configured to flow between the wick fixed to one flat surface of the wick and the other flat surface inside the container, and the wick is A fiber wick layer formed and a powder wick layer formed of the powder, the fiber wick layer on the one flat surface Is constant, the said the fiber wick layer powder wick layer are laminated, characterized in that the flow path to become narrow grooves in the inner wall surface to produce a capillary force and the working fluid of the container is formed is there.

Said fiber c dichroic that definitive to the present invention has a thin wire bundle formed by bundling to exchange difference a single thin line for other large number of fine lines even without the small, the thin line bundle May be formed by being twisted about its central axis.

The shape of the cross section of the wick which is perpendicular to the longitudinal direction of the front Symbol containers definitive to the present invention may include one of a rectangular shape and the flat semi-circular shape.

This pre-SL container definitive the invention, the wick is fixed to the wick by sintering in this state causes arranged to bias and in contact with the inner wall surface of the pipe, the wick is flat fixed inner wall surface It may be formed by being crushed to form a surface .

Before SL thin line definitive in this invention may comprise one of the copper and carbon fibers.

Further, the present invention provides a method of manufacturing a flat heat pipe for transporting heat by the working fluid to condense is heated to evaporate and heat radiation and, on the fiber wick layer formed by a large number of fine lines, powder a wick forming a wick powder wick layer are stacked to be formed by the body, at least the c Quick formed in the wick forming step over the inserted and the total length of the pipe to the pipe was placed in contact with a portion of the inner wall surface, a fixing step of fixing the front Symbol fiber wick layer on the inner wall surface by sintering in this state, then, the so said inner wall surface is a flat surface The pipe is crushed to flatten the pipe, and between the wick and another flat surface facing the flat surface to which the wick is fixed. E Bei a flattening step of vaporized the working fluid to form a steam flow path to flow, the inner wall surface to produce a capillary force and the flow path to become narrow grooves of said working fluid of said pipe is previously formed Is a manufacturing method characterized by

The manufacturing method according to the present invention includes a jig including a base plate on which a semicircular groove having the same curvature as the inner circumference of the pipe is formed, and a cover plate that covers the opening end of the groove. and, before Symbol wick forming step, laying the thin line in the groove for securing the fiber wick on the inner wall surface of the pipe, the powder was layered on top of the spread was fine line, then in the groove it may form form the wick by firing covered state by the cover plate.

The pre-Symbol Fiber c dichroic manufacturing method according to the invention may be formed by intersecting a single fine line to the other large number of fine lines even without its least.

In the manufacturing method according to the present invention , the cross-sectional shape of the wick perpendicular to the longitudinal direction of the flattened container may include one of a rectangular shape and a flat semicircular shape .

Before SL thin line of the manufacturing method according to the invention may comprise one of the copper and carbon fibers.

According to the present invention, since the wick is formed by mixing fine wires and powder, a large capillary force can be generated between the powders, and the working fluid smoothly and continuously between the fine wires. Thus, the flow resistance of the working fluid can be reduced. As a result, the reflux characteristics of the wick as a whole can be improved. The above wick is fixed in a raised state on one flat surface of a flat container, and the operation is performed by evaporating between the wick and the other flat surface facing the flat surface fixing the wick. Since the fluid is configured to flow, in other words, the wick and the other flat surface are not in contact with each other, and accordingly, an area where the working fluid evaporates in the wick can be secured. In other words, the space for the working fluid vapor to flow is not divided or reduced by the contact between the wick and the other flat surface. Therefore, by configuring as described above, it is possible to avoid or suppress the inhibition of the flow of the evaporated working fluid. As a result, the evaporation area of the liquid-phase working fluid in the wick is increased, the flow of the evaporated working fluid is smoothed, and as a result, the heat transport characteristics of the entire heat pipe can be improved. That is, even when the container is configured to be flat, excellent heat transport characteristics can be ensured. Moreover, the wick is fixed to the inner wall surface of the container over its entire length. In order to fix it, it is sufficient to sinter and fix the wick inserted in the container, and the manufacturability is good. In addition to this, it is given a deformation such as bending into the container, since wick is fixed therein is deformed so as to follow the container, in contact with the inner wall surface of the container deviates the position of the wick, with it Thus, a situation in which a closed space is generated inside the container and the flow of the evaporated working fluid is obstructed can be avoided or suppressed in advance, and a steam flow path along the wick can be reliably ensured.

Further, according to the present invention, c Quick comprises a fiber wick layer and the powder wick layer, fiber wick layer is fixed to the inner wall surface of the container, the powder wick layer is laminated thereon. Therefore, a large capillary force can be generated in the powder wick layer, and a smooth continuous flow of the working fluid can be formed in the fiber wick layer to reduce the flow resistance of the working fluid. In addition, since the fiber wick layer is disposed in contact with the inner wall surface of the container, the wettability of the working fluid with respect to the inner wall surface of the container can be improved. In addition to this, since the powder wick layer is arranged on the inner space side of the container, a larger evaporation area of the working fluid is ensured than when the fiber wick layer is arranged on the inner space side of the container. Can do.

Further, according to the present invention, since at least one of the thin line is crossed to the other fine line in c Quick and twisted words, at least one of the thin lines and other thin lines relatively gentle i.e. Therefore, in particular, the flow of the liquid-phase working fluid in the fiber wick layer is hardly inhibited. In addition, by making at least one thin line intersect with many other thin lines, the density difference of the fine lines in the longitudinal direction of the wick and the porosity between the fine lines can be adjusted. As a result, a smoothly continuous working fluid reflux path is formed between the thin wires, and the flow resistance of the working fluid can be reduced.

Then, according to the present invention, in the longitudinal direction of the container, i.e. the shape of the wick of a cross section perpendicular to the longitudinal direction of the wick that is formed in a rectangular or flat semicircular. Therefore, a wick can be arranged along a flat container.

Further, according to the present invention, since the cross section is flattened by crushing the pipe in the state of fixed by sintering the wick inside the circular pipe, it is good manufacturability.

Further, according to the present invention can also be used in c Quick, any copper wire and carbon fibers.

Lever by the manufacturing method according to the present invention, preformed wick of a mixture of fine wire and powder, is inserted the preformed wick inside the pipe, at least a portion of the pipe inner wall surface and pipe It arrange | positions in contact over the full length, and it is comprised so that the said wick may be fixed inside a pipe by baking. After that, the pipe is crushed and flattened so that the inner wall surface to which the wick is fixed becomes a flat surface, and between the wick and another flat surface facing the flat surface fixing the wick. The vaporized working fluid is configured to flow. Since the wick is formed by mixing fine wires and powder, a large capillary force can be generated between the powders, and a smoothly continuous working fluid reflux path can be formed between the fine wires. This can reduce the flow resistance of the working fluid. As a result, the reflux characteristic of the liquid-phase working fluid in the wick can be improved. Further, since the pipe is flattened after the wick is fixed inside the pipe, the wick can be deformed along with the deformation of the pipe. In addition to this, in the flattening process as described above, the pipe is flattened so that the working fluid vaporized can flow between the wick and the other flat surface opposite to the flat surface fixing the wick. Therefore, it is possible to expand the evaporation area of the working fluid in the wick, and the space where the working fluid vapor flows can be divided or reduced when the wick comes in contact with another flat surface. Can be prevented in advance. As a result, the evaporation area of the liquid-phase working fluid is increased, the flow of the evaporated working fluid is smoothed, and as a result, the heat transport characteristics of the entire heat pipe can be improved. That is, even when the container is configured to be flat, excellent heat transport characteristics can be ensured. Moreover, the wick is fixed to the inner wall surface of the container over its entire length. In order to fix it, it is sufficient to sinter and fix the wick inserted in the container, and the manufacturability is good. In addition to this, it is given a deformation such as bending into the container, since wick is fixed therein is deformed so as to follow the container, in contact with the inner wall surface of the container deviates the position of the wick, with it Thus, a situation in which a closed space is generated inside the container and the flow of the evaporated working fluid is obstructed can be avoided or suppressed in advance, and a steam flow path along the wick can be reliably ensured.

Also, the powder by the manufacturing method lever, the groove curved surfaces are formed to have substantially the same curvature as the inner wall surface of the pipe before to be flattened at least a portion of that, after the paved thin line according to the present invention Are covered and covered with a lid member and fired. Therefore, a curved surface having substantially the same curvature as the inner wall surface of the pipe before flattening can be formed on at least a part of the wick formed in the above process. And if this is inserted in the inside of a pipe, a wick can be fixed integrally by baking to the inner wall surface of at least one part of a pipe. In addition, when the pipe is flattened so that the curved surface to which the wick is fixed becomes a flat surface, a fiber wick layer is formed on the flat surface, and a powder wick layer is formed thereon. As a result, since the fiber wick layer is in contact with the flattened inner wall surface of the pipe, the wettability of the liquid-phase working fluid to the inner wall surface of the pipe can be improved, and the fiber wick layer is smoothly continuous. The flow path of the working fluid can be reduced by forming a return path for the working fluid. In addition, a large capillary force can be generated in the powder wick layer. Furthermore, since the powder wick layer is disposed on the inner space side of the container, a larger evaporation area of the working fluid can be secured as compared with the fiber wick layer.

Moreover, lever by the manufacturing method according to the present invention, since at least one of the thin line is crossed to the other fine line in c Quick, in other words, at least one of the thin lines and the other fine line is relatively Since it is gently twisted, the flow of the working fluid in the liquid phase particularly in the fiber wick layer is hardly inhibited. In addition, by making at least one thin line intersect with many other thin lines, the density difference of the fine lines in the longitudinal direction of the wick and the porosity between the fine lines can be adjusted. As a result, a smoothly continuous working fluid reflux path is formed between the thin wires, and the flow resistance of the working fluid can be reduced.

The lever by the manufacturing method according to the present invention, the shape of the cross section of the wick which is perpendicular to the longitudinal direction of Bian Tairaka been container that is formed in a rectangular or flat semicircular. Therefore, a wick can be arranged along a flat container.

Further, according to the present invention can also be used in c Quick, any copper wire and carbon fibers.

It is a figure showing typically a sectional view of a flat type heat pipe concerning this invention. It is a figure which shows typically an example of a structure of the jig | tool used in order to form the wick which concerns on this invention. It is a figure which shows typically the process of manufacturing the wick in the heat pipe which concerns on this invention. It is sectional drawing of the round heat pipe which is an intermediate product in the manufacture process of the flat type heat pipe which concerns on this invention.

  Next, the present invention will be specifically described. This invention is a heat pipe characterized by the structure of the wick. A heat pipe wick according to the present invention includes a fiber wick layer formed by a number of fine wires bundled without using a binding tool, and a powder wick layer formed by powder laminated thereon. ing. These fine wires and powders may be any material that has excellent wettability with the working fluid sealed in the container, such as copper or carbon. More specifically, in the fiber wick layer, at least one or many thin wires out of the bundled thin wires intersect with many other thin wires. That is, it is twisted relatively gently. This is for adjusting the gap between the fine wires for generating the capillary force and the density of the fine wires in the longitudinal direction of the wick, and preventing the bundle of fine wires from being scattered. Therefore, a thin wire that maintains the shape after being crossed is preferable, and a thin metal wire such as a copper wire is preferable.

  In the present invention, the wick as described above is formed in advance, the pre-formed wick is inserted into the container, and the fiber wick layer of the wick is placed in contact with a part of the inner wall surface of the container. The wicks are then fixed in the container by sintering them. Here, by ensuring a gap between the wick and the other inner wall surface facing the one inner wall surface to which the wick is fixed, the working fluid vaporized in the gap can flow. . Thereafter, the working fluid is sealed inside the container. The container is basically an airtight hollow container, and a hollow pipe is used for a heat pipe used for transporting heat between locations apart from each other. Since it is necessary to transfer heat between the inside and the outside of the container, the container is preferably made of a material having high thermal conductivity, and for example, a copper tube is preferably used. Further, a narrow groove that serves as a flow path for the working fluid and causes capillary action may be formed on the inner wall surface of the container. That is, a groove tube may be used as the container.

  As described above, the wick is fixed to the inner wall surface of the container. Specifically, the wick is heated to a predetermined temperature in a state where the wick is disposed inside the container, thereby causing sintering between the fiber wick layer and the container and bonding them together. A so-called surplus space excluding the wick inside the container serves as a steam flow path through which the working fluid steam flows. Here, the predetermined temperature is, for example, a temperature before and after the melting point of copper when a thin wire or a container is formed of copper, and more specifically, a temperature slightly lower than the melting point temperature. Yes, when these are heated to that temperature, adjacent fine wires or containers and fine wires in contact with them are combined.

  On the other hand, the working fluid is a fluid that heats and evaporates, dissipates heat and condenses, thereby transporting heat in the form of latent heat, and is appropriately selected according to the temperature at which the heat pipe is used. For example, water, alcohols such as methanol and ethanol, ammonia, and alternative chlorofluorocarbon are used as the working fluid. The working fluid is sealed inside the container in a state where non-condensable gas such as air is deaerated from the inside of the container.

  Therefore, in the heat pipe according to the present invention, when heat is applied to a part of the container and the other part is cooled, the working fluid is heated and evaporated, and the steam flows toward a place where the temperature and pressure are low. Then, it dissipates heat and condenses. The steam flow path is a flow path along the wick. In the present invention, the vapor wick layer is also disposed between the powder wick layer and another inner wall surface facing a part of the inner wall surface of the container fixing the wick. A steam flow path is secured. Further, since the wick is fixed to the inner wall surface of the container by sintering, a steam flow path is secured even if the heat pipe is deformed such as bending. As a result, the working fluid vapor flows sufficiently and sufficiently, and the heat transport characteristics as a heat pipe are improved. In addition, as described above, a steam flow path is secured between the powder wick layer and the other inner wall surface, in other words, the powder wick layer and the other inner wall surface are not in contact with each other. The evaporation area of the working fluid is ensured.

  On the other hand, the condensed working fluid permeates the wick, and flows toward a portion where evaporation occurs using a gap between fine wires constituting the wick or between powders as a flow path. That is, when the working fluid evaporates, the meniscus formed in the fiber wick layer and the powder wick layer constituting the wick decreases, and accordingly, capillary force is generated, and the capillary force is used as a pumping force to generate a liquid phase working fluid. Reflux to the evaporation part side. More specifically, in the powder wick layer, a large capillary force is generated due to a small gap between the powders, and a large pumping force is generated. On the other hand, in the fiber wick layer, the thin wire bundle is continuous over its entire length, and not only there is no place where the thin wire bundle is fastened for bundling, but at least one thin wire is a number of other thin wires. Are adjusted so that the gap and density between the thin wires are constant or substantially constant in the longitudinal direction of the wick. Therefore, the so-called reflux path formed between the thin wires is also smoothly continuous, and thus the resistance to the flow of the liquid-phase working fluid is reduced. As a result, in the wick according to the present invention, the reflux characteristic of the liquid-phase working fluid is good. In addition, since the wick is fixed by sintering, if the wick is inserted into the pipe and heated from the outside, the wick can be fixed to the pipe over its entire length, and the work is easy and the productivity is improved. Become good.

  Next, an example of a heat pipe according to the present invention will be described together with a manufacturing method. FIG. 2 schematically shows an example of the configuration of a jig used to form the wick according to the present invention. The jig 1 includes a base plate 3 in which a plurality of grooves 2 are formed, and a cover plate 4 that covers the open end 2 a of each groove 2. In the example shown here, the base plate 3 is formed in a square shape, and a plurality of grooves 2 are formed in parallel to any one flat surface and any one piece on the flat surface. The groove 2 is for forming a wick having a predetermined shape, and therefore the shape of at least a part of the groove 2 is the same as the shape of at least a part of the inner wall surface of the container to which the wick is inserted and fixed. It is configured to be almost the same. As an example, when a hollow cylindrical pipe is used as a container, the base plate 3 has a semicircular groove 2 having substantially the same curvature as the inner circumference of the pipe as shown in FIG. It is formed. As described above, the cover plate 4 covers the open end 2a of each groove 2. Therefore, in the example shown in FIG. 2, the cover plate 4 is formed in a square shape like the base plate 3. A wick having a shape along a space formed by the cover plate 4 is formed. In this way, the jig 1 shown in FIG. 2 is configured to function as a so-called mold for forming a wick having a predetermined shape. Each of these plates 3 and 4 is preferably made of a material different from the member constituting the wick, such as SUS or carbon.

The manufacturing process of the wick using the jig 1 will be described. First, the thin wire bundle 5 is formed by bundling at least one or many thin wires so as to intersect with the other many thin wires. This is because each thin wire is bundled relatively gently, and a space between the thin wires is secured , and the porosity and density between the thin wires are adjusted to be constant or substantially constant in the longitudinal direction of the thin wire bundle 5. is there. Specifically, the thin wire is a copper wire having a direct connection of about 0.05 to 1.0 mm, and bundles 300 to 500 wires. Then, the thin wire bundle 5 is spread in each groove 2 of the base plate 3 as shown in FIG. In addition, by twisting the thin wire bundle 5 around the central axis, the fine wires can be bound to each other more strongly than the above configuration, and the state can be maintained.

  Next, as shown in FIG. 3B, the powder 6 is filled up to the opening end 2 a of the groove 2 on the thin wire bundle 5. In the example shown here, the powder 6 is a copper powder having a particle size in the range of 80 μm to 250 μm. This is because the fine wire bundle 5 and the powder 6 are integrated by sintering. In the example shown here, the ratio of the copper wire and the copper powder is such that the ratio of the copper wire and the copper powder is 1: 1 in the cross-sectional area of the wick. Thereafter, as shown in FIG. 3 (c), the cover plate 4 is used to cover each groove 2, which is sent to a heating furnace (not shown) while being kept substantially horizontal, and heated. As described above, the heating temperature is about 800 ° C. to 1000 ° C. when the fine wire and the powder are made of copper. By doing this, the fine wire and the powder are formed in the space formed by the groove 2 and the cover plate 4. The wick 7 is formed by sintering along the shape. At the same time, adjacent copper wires and powders are sintered and joined together. As a result, this wick 7 has a structure in which a fiber wick layer 7a and a powder wick layer 7b are laminated. And after taking out the jig 1 in which the wick 7 was formed from the heating furnace and cooling, when the base plate 3 and the cover plate 4 were removed, as shown to (d) of FIG. 3, it was shape | molded by semicircle shape. Wick 7 is left.

  On the other hand, a pipe having a wall thickness of 0.2 to 0.3 mm and an outer diameter of 3.0 to 6.0 mm (inner diameter of 2.4 to 5.6 mm) subjected to cleaning such as degreasing is prepared, and this pipe has a predetermined length The container 8 is cut. When copper wire or copper powder is used as the wick 7, a copper pipe is used as the container 8. Then, the wick 7 formed in advance as described above is inserted into the container 8. Although not shown in detail, as an example, the wick 7 is inserted into the container 8 using another jig. This other jig is for inserting the wick 7 into the container 8 and placing the wick 7 in contact with the inner wall surface of the container 8. Therefore, the other jig is a container together with the wick 7. The wick 7 is inserted into the container 8, placed at a predetermined location in the container 8, and then taken out from the container 8. Therefore, the outer shape of the wick 7 and other jigs is configured to be smaller than the inner diameter of the container 8. Then, after the wick 7 is arranged inside the container 8, the wick 7 is cut into a predetermined length.

  FIG. 4 schematically shows a cross-sectional view of the container in a state where the wick is arranged inside the container. In the example shown in FIG. 4, an example is shown in which a so-called groove tube is used as the container 8 which is a flow path for the working fluid on the inner wall surface thereof and in which a narrow groove that causes capillary action is formed. A so-called bare pipe in which the groove is not formed may be used as the container 8. Here, when the wick 7 is arranged inside the container 8, as shown in FIG. 4, the fiber wick layer 7a of the wick 7 is arranged so as to contact the inner wall surface of the container 8, and the powder wick is arranged. It arrange | positions so that the layer 7b may be exposed to the internal space side of the container 8. FIG.

  Next, the container 8 into which the wick 7 is inserted is sent to a heating furnace (not shown) while being kept substantially horizontal and heated. When the wick 7 and the container 8 are made of copper, the heating temperature is about 800 ° C. to 1000 ° C. By doing so, the wick 7 is baked in a state where it is biased to a part of the inner wall surface of the container 8 over its entire length. Tied and fixed.

  After the container 8 to which the wick 7 is fixed is taken out from the heating furnace and cooled, the one end portion of the container 8 is swaged and the end portion is welded and sealed. That is, so-called bottom swaging and bottom welding are performed. In addition to these processes, swaging processing of the other end, that is, top swaging processing is performed. In this way, a substantial container 8 is produced.

  By performing the top swaging process, a nozzle-like portion is formed at one end of the container 8, and liquid injection is performed using this. That is, the working fluid is injected into the container 8. In that case, it is necessary to deaerate non-condensable gas such as air from the container 8. Therefore, the injection is performed by injecting the working fluid after vacuum degassing, after injecting an excessive amount of working fluid, May be carried out by a conventionally known method such as a method of boiling non-condensable gas by boiling. And after crushing the part opened for liquid injection, it welds and seals. So-called top welding is performed.

  When a pipe having a circular cross section perpendicular to the axial direction as described above is used as the material of the container 8, the round pipe type heat pipe manufactured as described above is crushed in the radial direction. The flat heat pipe 9 is 2.0 mm thick. FIG. 1 schematically shows a cross-sectional view of a flat heat pipe according to the present invention. In a round pipe type heat pipe as shown in FIG. 4, when the pipe is crushed so that the inner wall surface to which the wick 7 is fixed becomes a flat surface, the arc-shaped portion of the wick 7 is pulled along with the deformation. It is stretched and flattened. That is, the fiber wick layer 7a becomes flat as the container 8 becomes flat. On the contrary, as shown in FIG. 4, the flat or almost flat portion of the powder wick layer 7 b that is exposed to the inner space side of the container 8 is deformed as the container 8 is deformed. Arc shape. As a result, as shown in FIG. 1, the wick 7 is in a state where it rises like a mountain on the flat surface inside the container 8, and the wick 7 is fixed over the width direction of the flat surface. Become. Here, the portions of the powder wick layer 7b that are in contact with the inner wall surface of the container 8 become both ends of the flat surface as shown in FIG. 1 after flattening. That is, when flattening is performed, the fiber wick layer 7a is encased by the flat surface of the container 8 and the powder wick layer 7b. Moreover, when making the container 8 flat, it is made for the top part of said convex-shaped wick 7 not to contact the inner wall face of the container 8 which opposes this. This is to secure the flow path of the vaporized working fluid inside the container 8, and in addition, by not contacting the wick 7 and the inner wall surface of the container 8, the working fluid in the wick 7 is correspondingly reduced. This is to ensure the evaporation area. The distance between them is, for example, a distance that allows the evaporated working fluid to flow, or a distance that does not generate a capillary force between them. Therefore, the space portion between the inner wall surface of the container 8 and the wick 7 formed in this way is a vapor flow path 10 of the working fluid that is vaporized.

  When the curved rectangular wick is placed inside the container 8 and flattened as described above, the shape of the wick changes with the deformation of the container 8, as in the example shown in FIG. As a result, the shape of the wick can be made rectangular.

  On the other hand, in the case of forming a curved or bent flat heat pipe, the wick 7 is fixed after the round pipe heat pipe is bent or bent into a predetermined shape, that is, after being bent. The container 8 is crushed and flattened in the radial direction so that the inner wall surface becomes a flat surface. Further, even when a flat heat pipe that is curved or bent is formed in this way, the top of the convex wick 7 does not come into contact with the inner wall surface of the container 8 facing the flat heat pipe after the flat processing. To do. Therefore, the space formed by the inner wall surface of the container 8 and the wick 7 serves as a vapor flow path 10 for the working fluid vaporized. In addition, since said wick 7 is being fixed to the inner wall surface of the container 8 by sintering, it deform | transforms according to the curve or bending of the container 8, and, as a result, the steam flow path 10 along the wick 7 is ensured. .

  As described above, in the flat heat pipe 9 according to the present invention shown in FIG. 1, the wick 7 includes the fiber wick layer 7a and the powder wick layer 7b, so that the fiber wick layer 7a is between the thin wires. A smooth and continuous reflux path for the working fluid is ensured, and the powder wick layer 7b generates a large capillary force, so that the reflux characteristics of the liquid-phase working fluid can be improved. In addition to this, the fiber wick layer 7a is fixed in a flat shape over the width direction of one flat surface of the hollow flat container 8, in other words, the wick 7 and the inner wall surface of the container 8 By expanding the contact area, the liquid phase working fluid can be spread in the width direction of the container 8. As a result, the area in which the flat heat pipe according to the present invention can be thermally connected to the heat source in the width direction of the container 8 can be expanded. Moreover, since the powder wick layer 7b is laminated | stacked on the fiber wick layer 7a, and is arrange | positioned inside the flat type heat pipe 9 at the vapor | steam flow path 10 side, a big evaporation area can be ensured with the porous structure. Furthermore, since the wick 7 of the flat heat pipe 8 according to the present invention has the powder wick layer 7b disposed so as to wrap the fiber wick layer 7a as described above, the working fluid flows smoothly. The working fluid can be effectively supplied from the fiber wick layer 7a to the powder wick layer 7b. In addition to these, even when deformation such as bending is applied to the container 8, the wick 7 is deformed in accordance with the deformation of the container 8, so that the steam flow path 10 can be reliably secured. In addition to these, since the working fluid vapor can flow between the wick 7 and the other flat surface opposite to the flat surface to which the wick 7 is fixed, the wick 7 and the inner wall surface are separated from each other. Reduction of the evaporation area due to contact can be suppressed. Further, since the wick 7 and the container 8 are not divided into two due to the contact between the wick 7 and the container 8, an increase in the flow velocity of the working fluid vapor in the steam channel 10 can be suppressed. A decrease in heat transport capability can be suppressed. As a result, in the flat heat pipe 9 according to the present invention, its heat transport capability can be made higher than ever before. Then, by using a groove tube as shown in FIG. 4 as the container 8, the contact area between the working fluid and the container 8 can be expanded, and the return path for the working fluid smoothly and continuously in the groove. The heat transport capability can be further improved. Further, in the present invention, since the wick 7 formed in advance is inserted into the inside of the container 8 and fixed, the flattening is performed. Therefore, when a groove pipe is used as the container 8, the groove is formed. Can be prevented from being blocked by fine wires or powders constituting the wick.

  As described above, the flat heat pipe 9 using the wick 7 according to the present invention is as thin as about 2.0 mm, and in addition, the heat transport characteristics can be made higher than before, so that a small electronic device can be obtained. The mountability for is excellent.

  7 ... wick, 7a ... fiber wick layer, 7b ... powder wick layer, 8 ... container, 9 ... flat heat pipe.

Claims (7)

In a flat heat pipe that transports heat by a working fluid that is heated to evaporate and radiates and condenses,
A container formed in a flat shape and filled with the working fluid;
A wick formed by mixing a large number of fine wires and powder,
The wick is fixed to one flat surface inside the container over the entire length of the container ,
The evaporated working fluid is configured to flow between the wick fixed to one flat surface and the other flat surface inside the container,
The wick includes a fiber wick layer formed by the fine wires, and a powder wick layer formed by the powder,
The fiber wick layer is fixed to the one flat surface, and the powder wick layer is laminated on the fiber wick layer,
A narrow groove that forms a capillary force on the inner wall surface of the container and serves as a flow path for the working fluid is formed,
The fiber wick has a fine wire bundle formed by bundling at least one fine wire so as to intersect with many other fine wires, and the fine wire bundle is twisted around its central axis. A flat heat pipe characterized by   The flat heat pipe according to claim 1, wherein the cross-sectional shape of the wick orthogonal to the longitudinal direction of the container includes one of a rectangular shape and a flat semicircular shape. The thin line, flat heat pipe of claim 1 or 2, characterized in that it comprises one of the copper and carbon fibers. In a manufacturing method of a flat heat pipe that transports heat by a working fluid that is heated and evaporated and radiates and condenses,
A wick forming step of forming a wick in which a powder wick layer formed of powder is laminated on a fiber wick layer formed of a plurality of fine wires;
The fiber wick is formed by inserting the wick formed in the wick forming step into a pipe and placing the wick in contact with at least a part of the inner wall surface over the entire length of the pipe and sintering in that state. A fixing step of fixing the layer to the inner wall surface;
Thereafter, the pipe is crushed so that the inner wall surface becomes a flat surface to flatten the pipe, and vaporization is performed between the wick and another flat surface facing the flat surface to which the wick is fixed. A flattening step for forming a steam flow path through which the working fluid flows,
A narrow groove that creates a capillary force on the inner wall surface of the pipe and serves as a flow path for the working fluid is formed in advance,
The fiber wick is formed by intersecting at least one fine wire with a plurality of other fine wires, and manufacturing the flat heat pipe. A base plate in which a semicircular groove having the same curvature as the inner circumference of the pipe is formed, and a cover plate that covers an opening end of the groove;
In the wick forming step, the fine wire is spread over the groove to fix the fiber wick to the inner wall surface of the pipe, the powder is laminated on the fine wire, and then the groove is placed on the cover plate. The method for producing a flat heat pipe according to claim 4 , wherein the wick is formed by firing in a state where the flat heat pipe is covered. The flat shape according to claim 4 or 5 , wherein a shape of a cross section of the wick orthogonal to a longitudinal direction of the flattened container includes one of a rectangular shape and a flat semicircular shape. Heat pipe manufacturing method. The method for manufacturing a flat heat pipe according to any one of claims 4 to 6 , wherein the thin wire includes one of a copper wire and a carbon fiber.

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