JP5809529B2 - Manufacturing method of sintered heat pipe - Google Patents

Description

  The present invention relates to a method for manufacturing a heat pipe that transports heat by the flow of a working fluid enclosed in a container. In particular, the present invention relates to a method for manufacturing a sintered heat pipe formed by sintering metal powder as a wick for returning a working fluid to an evaporation section.

  The heat pipe is used for cooling a device such as a CPU of a personal computer. The heat pipe is a sealed metal body in which a non-condensable fluid is degassed and an appropriate amount of hydraulic fluid is enclosed. The working fluid sealed inside evaporates by being heated from the outside of the container (evaporating part), and when cooled, the vapor is condensed and returned to the working liquid (condensing part), and transports heat as latent heat. Since heat is transported as latent heat, heat transport can be performed even with a small temperature difference between the evaporation section and the condensation section.

  A hollow tube is used for a general heat pipe container. Since this container needs to conduct heat inside and outside, it is made of a material with high thermal conductivity. For example, metals such as copper and aluminum are used. Moreover, water, alcohol, methanol, alternative chlorofluorocarbon, ammonia, etc. are used for the hydraulic fluid.

  In the container, the working fluid condensed in the condensing part is returned to the evaporation part. When the evaporating unit is located below the condensing unit, a thermosiphon heat pipe that drops and returns the working fluid by gravity can be used.

  However, when the evaporation unit is positioned above the condensation unit or both are positioned horizontally due to the positional relationship between the evaporation unit and the condensation unit, the surface tension of the hydraulic fluid is used for the reflux of the hydraulic fluid. Therefore, a wick structure is required inside the container.

  As the wick structure, a linear body obtained by bundling a plurality of fine wires, a mesh body such as a mesh, or a sintered body obtained by sintering powder such as copper powder is used. It is known that a powder using powder can obtain a high surface tension.

  In order to fix the powder in the container, as shown in Patent Document 1, a core rod having a notch is inserted into the container, and a metal is formed in the space formed by the container and the core rod. Fill with powder. It is known to fix the container by sintering by heating the container with the metal powder and the core rod inserted.

JP 2009-68787 A

  At the time of manufacture, in Patent Document 1, a metal powder is filled into a space formed by a core bar having a notch and a container. When fixing a sintered metal by heating, there exists a problem that a core rod and a sintered metal will adhere and it will become difficult to pull out a core rod.

  If the core rod cannot be easily pulled out after fixing the sintered metal, it takes time to move to the next step during manufacturing. Therefore, the problem which reduces the productivity of a heat pipe arises.

  The present invention is a method for manufacturing a sintered heat pipe capable of facilitating the extraction of a core bar after fixing a sintered metal at the time of manufacturing a wick structure of a heat pipe.

The present inventor has intensively studied to solve the conventional problems described above. As a result, according to one aspect of the present invention, a tube-shaped container is prepared, and a splittable core rod having a plurality of cutout portions each having a flat surface is inserted into the container along the long axis direction. Filling the metal powder into the space formed by the notch and the inner wall of the container, and heating the container with the metal powder and the core rod inserted to sinter the metal powder. Each of the plurality of cutout portions includes a step of forming a wick structure, a step of dividing and pulling the core rod from the container, a step of flattening the container, and a step of enclosing a working fluid in the container. Is formed in a V shape with an adjacent notch, the core rod is divided into two or more, all flat surfaces of the divided core rod are in contact with the metal powder, and the metal powder in each of the divided core rods Metal powder than the area in contact with Area which is not in contact is a manufacturing method of a large sintered heat pipe.

In one aspect of the present invention, there are two space portions formed by the notch portion of the core rod and the inner wall of the container, and two wick structures are formed on one flat surface of the flattened container. May be .

  According to the present invention, since the core rod is divided, the core rod can be pulled out from the core rod that requires less pulling force than the core rod not fixed to the metal powder or other core rods. As a result, a space is generated in the portion where the core rod is pulled out in the container, and a force can be applied to the core rod remaining in the space direction, so that the fixation between the core rod and the metal powder can be easily peeled off.

  The shape and the number of the wick structure of the sintered heat pipe can be changed by the shape and the number of the notch portions of the core rod.

  Since all the divided core rods are in contact with the metal powder, the pulling force can be reduced in inverse proportion to the number of division.

It is sectional drawing which shows an example of the sintering heat pipe which concerns on embodiment of this invention. It is a schematic diagram explaining an example of the manufacturing method of the sintered heat pipe which concerns on embodiment of this invention. It is the schematic which shows the AA cross section of the tube-shaped container shown in FIG.2 (b). It is sectional drawing which shows the other example of the filling process of the metal powder in the manufacturing method of the sintered heat pipe which concerns on embodiment of this invention. It is sectional drawing which shows the other example of the filling process of the metal powder in the manufacturing method of the sintered heat pipe which concerns on embodiment of this invention. It is a cross section which shows the other example of the filling process of the metal powder in the manufacturing method of the sintered heat pipe which concerns on embodiment of this invention.

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

 The following embodiments of the present invention exemplify apparatuses and methods for embodying the technical idea of the present invention. The technical idea of the present invention is based on the material and shape of component parts. The structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the technical scope described in the claims.

  The sintered heat pipe according to the embodiment of the present invention includes a container 1 and a wick structure 6 as shown in FIG. The container 1 has a flat tube shape. The wick structure 6 is provided on the flat portion of the container 1. Cavities 8 are formed between the inner wall of the container 1 and the wick structure 6 at both ends of the container 1.

  The container 1 is a tubular pipe made of metal such as copper having high thermal conductivity. The wick structure 6 is made of a porous sintered metal such as copper, bronze, and stainless steel. A sintered metal is a metal powder joined by sintering. The pores of the sintered metal can be adjusted by adjusting the size of the metal powder such as spherical powder or irregular powder.

  Next, a method for manufacturing a sintered heat pipe according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 2A, a container 1 and a core rod 2 are prepared. For example, as the container 1, a copper pipe having a thickness of 0.3 mm and an outer diameter of 3.0 to 6.0 mm that has been cleaned such as degreasing is cut into a predetermined length and used. The core rod 2 has a cross section having a shape obtained by flattening a part of a circle. The core rod 2 can be divided into two parts, the first and second divided portions 3a and 3b. Flat cutout portions 4a and 4b are formed in the first and second divided portions 3a and 3b, respectively. The length of the core rod 2 is made longer than the length of the container 1. The core rod 2 is made of a material that is difficult to adhere to the wick structure 6, for example, carbon, ceramic, stainless steel, or the like.

  As shown in FIGS. 2B and 3, the core rod 2 is inserted into the tubular container 1. A metal powder 5 is filled in a space formed between the notches 4 a and 4 b of the first and second divided portions 3 a and 3 b of the core rod 2 and the inner wall of the container 1. The metal powder 5 is, for example, copper powder having a particle size of 80 μm to 250 μm, such as spherical powder or irregular powder. The amount of the metal powder 5 enclosed can be adjusted by the size and shape of the notches 4a and 4b.

  As shown in FIG. 2B, in a state where the filled metal powder 5 is fixed by the core rod 2, the metal powder 5 is heated at a sintering temperature before and after the melting point of the metal powder 5 to obtain a porous sintered metal. A wick structure 6 is formed. When the container 1 and the metal powder 5 are copper, a sintering temperature of about 800 ° C. to 1000 ° C. is selected. The wick structure 6 is formed in contact with the inner wall of the container 1 and the notches 4a and 4b. After the wick structure 6 is formed, the first and second divided portions 3a and 3b of the core rod 2 are pulled out in order from the easier one. As a result, as shown in FIG. 2 (c), the core rod 3 is pulled out to form the cavity 8.

  After the core rod 2 is pulled out, a swaging process is performed on one end of the container 1, and bottom welding is performed to seal the one end. In addition, the other end portion of the container 1 is subjected to a swaging process to provide a nozzle-like liquid injection port.

  A non-condensable gas such as air inside the container 1 is deaerated using the liquid injection port, and then a working liquid such as water, methanol, ethanol, alternative chlorofluorocarbon, or ammonia is injected. Non-condensable gas can be degassed by vacuum degassing or by heating and expelling a non-condensable gas by injecting an excess amount of hydraulic fluid in advance and heating the container 1 to boil the hydraulic fluid. Etc. are used.

  After the injection, the nozzle-like injection port that has been opened is closed and sealed by welding. The round pipe type heat pipe thus manufactured is crushed in the radial direction to obtain a flat type heat pipe. At this time, when it is necessary to bend or bend the major axis direction of the heat pipe, the round pipe type heat pipe is bent or bent into a predetermined shape and then flattened by being crushed in the radial direction. Also in these steps, since the wick structure 6 is fixed by sintering in the container 1, the positional relationship between the working fluid flow path and the steam flow path is ensured in the long axis direction.

  In the embodiment, the core rod 2 is divided into approximately two equal parts into the first and second divided portions 3a and 3b. The core rod 2 is in contact with the wick structure 6 at the notches 4a and 4b. The area of the notch 4a is substantially equal to the area of the notch 4b. The area where each of the first and second divided portions 3 a and 3 b contacts the wick structure 6 is approximately halved compared to the case of the core rod 2. Accordingly, the force for pulling out each of the first and second divided portions 3a and 3b can be reduced.

  Moreover, the 1st division part 3a with which extraction is easy among the 1st and 2nd division parts 3a and 3b is extracted, for example. When the remaining second divided portion 3b is pulled out, a force can be applied in the direction of the space generated by the first divided portion 3a being pulled out. As a result, even when the second divided portion 3b is fixed to the wick structure 6, the fixed portion can be peeled off. Further, depending on the material of the core rod 2, by applying a pulling force, a slight deformation such as bending or distortion occurs temporarily. In such a case, by applying a force in the spatial direction to the second divided portion 3b, it becomes easier to peel off the fixing portion.

  As described above, the core rod 2 can be divided into first and second divided portions 3a and 3b having flat cutout portions 4a and 4b. However, the shape of the notch and the number of divisions are not limited. Moreover, the number of the space parts formed by the notch and the inner wall of the container 1 may be plural. For example, as shown in FIG. 4, a core rod 2 that can be divided into first to third divided portions 3c, 3d, and 3e having flat cutout portions 4c, 4d, and 4e may be used. The metal powder 5 is filled in contact with each of the cutout portions 4c, 4d, and 4e of the first to third divided portions 3c, 3d, and 3e. Since the core rod 2 is divided into three parts, the pulling force can be reduced to about 1/3.

  Moreover, as shown in FIG. 5, you may use the core rod 2 which made the notch part 4f, 4g of each 1st and 2nd division | segmentation part 3f, 3g into V shape. A space between the notch 4f and the inner wall of the container 1 and a space between the notch 4g and the inner wall of the container 1 are formed separately. The metal powder 5 is filled in contact with each of the notches 4f and 4g. As a result, when the container 1 is flattened, two wick structures 6 are formed separately at both ends of the flat container 1.

  Moreover, as shown in FIG. 6, you may use the core rod 2 which has the 1st-4th division | segmentation part 3h, 3i, 3j, 3k. The cutout portions 4h and 4i of the first and second divided portions 3h and 3i and the cutout portions 4j and 4k of the third and fourth divided portions 3j and 3k are V-shaped. The metal powder 5 is filled in contact with each of the notches 4h, 4i, 4j, and 4k. Since the core rod is divided into four parts, the pulling force can be reduced to about 1/4.

  Thus, according to the embodiment, the core rod 2 can be divided into a plurality of divided portions, and since all the divided portions are in contact with the metal powder 5, the pulling force is inversely proportional to the number of divided portions. Can be small. Further, the shape and the number of the wick structures 6 can be adjusted by the shape of the notch portion of the core rod 2.

  Needless to say, the above-described details may be further modified without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Core rod, 3a ... 1st division part, 3b ... 2nd division part, 4a, 4b ... Notch part, 5 ... Metal powder, 6 ... Wick structure.

Claims (2)

Preparing a tube-shaped container, and inserting a separable core rod having a plurality of cutout portions each having a flat surface along the major axis direction into the container;
Filling a metal powder into a space formed by the notch and the inner wall of the container;
Heating the container with the metal powder and the core rod inserted, and sintering the metal powder to form a wick structure;
Dividing and extracting the core rod from the container;
A step of flattening the container;
A step of enclosing a working fluid in the container ,
Each of the plurality of notches is V-shaped with an adjacent notch,
The core rod is divided into two or more, and all the flat surfaces of the divided core rod are in contact with the metal powder, and the area of the divided core rod is in contact with the metal powder. A method for producing a sintered heat pipe, characterized in that the area not in contact with the metal powder is large . There are two spaces formed by the notch and the inner wall of the container, and two wick structures are formed on one flat surface of the container that has been flattened. The method for producing a sintered heat pipe according to claim 1.

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