JP4485013B2 - Plate type heat pipe and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pipe that radiates heat generated from a heating element such as a semiconductor element and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, a heat sink is used for cooling a heating element such as a semiconductor element mounted on an electronic device. One type of heat sink uses a heat pipe. The heat pipe is one in which a sealed medium inside is evacuated and then a heat medium such as water, butane, or alcohol is enclosed therein. The part of the heat pipe to which the heating element is attached becomes a heat receiving part, and heat is transmitted from the heating element. The heat transferred to the heat receiving unit evaporates the heat medium in the heat pipe of the heat receiving unit. The steam moves to the heat radiating part of the heat pipe and dissipates heat, and the steam returns to the liquid. The heat of the heating element diffuses due to the change or movement of the phase of the heat medium in the sealed space. With this heat pipe, the heat transmitted from the heating element is spread over the entire surface of the heat pipe and dissipated.
[0003]
One type of such heat pipe is a meandering pore heat pipe. This meandering pore heat pipe has the following characteristics (see Japanese Patent Laid-Open No. 4-190090).
(1) Both ends of the pores (heat medium passage) are connected to each other so as to be freely flowable and sealed.
(2) The part with the pore is the heat receiving part, and the other part is the heat radiating part.
(3) The heat receiving portions and the heat radiating portions are alternately arranged, and the pores meander between the two portions.
(4) A two-phase condensable heat medium is enclosed in the pores.
(5) The inner wall of the pore has a diameter that is equal to or less than the maximum diameter that allows the heat medium to circulate or move while the inside of the pore is always closed.
[0004]
Conventionally, the following two methods are known as typical manufacturing methods for plate-type meandering pore heat pipes.
(1) Method using a grooved flat plate disclosed in JP-A-7-63487:
6A and 6B are diagrams showing a method of manufacturing a heat pipe disclosed in Japanese Patent Application Laid-Open No. 7-63487. FIG. 6A is a sectional view, and FIG. 6B is a partially broken plan view showing an internal structure. It is.
In this method, first, a series of meandering narrow grooves 54 are formed on the surface of a thin metal plate 53 with good thermal conductivity by cutting or electric discharge machining. Next, a flat thin plate 55 is stacked on the surface of the thin plate 53, and both the plates 53 and 55 are laminated by brazing. The narrow grooves 54 formed in the thin plate 53 become sealed meandering pores (heat medium passages) 56 by stacking. A heat medium is sealed in the tunnel 56.
[0005]
(2) A method using a porous flat tube of extruded material disclosed in JP-A-9-49692:
FIG. 7 is a view showing a method of manufacturing a heat pipe disclosed in Japanese Patent Laid-Open No. 9-49692. FIG. 7 (A) is a plan sectional view for explaining the first step, and FIG. It is a plane sectional view for explaining the 2nd process.
In the first step, a porous flat tube 63 of light metal such as aluminum or magnesium is used as a raw material. The porous flat tube 63 has a flat plate-like outer shape as a whole, and a large number of through-holes 64 arranged in parallel inside are formed by extrusion molding. Thereafter, the partition wall 66 on the end face of the pore 64 is cut every other line by the cut part 66a having a predetermined depth, and the cut part 66b is cut by shifting one line at the opposite end face. In the second step, the edge portions 68a and 68b are welded to both end surfaces, leaving a predetermined length from the deepest portion of the cut portions 66a and 66b. The pores 64 communicate with each other at the end portion to form a series of meandering pores (heat medium passages), in which the heat medium is enclosed.
[0006]
[Problems to be solved by the invention]
However, the above manufacturing method has the following insufficient points.
In the method (2), since extrusion molding is used, the number of grooves, pitch, wall thickness or material of the partition cannot be freely selected, and must be selected from commercially available products with limited types. . Furthermore, electrical discharge machining is required for excision at both ends, and special know-how and equipment are required.
On the other hand, in the method of cutting a groove in the flat plate of (1) above, the processing cost increases according to the length and number of grooves, and is not suitable for an inexpensive mass production process.
[0007]
The present invention has been made in view of such problems, and an object of the present invention is to provide a plate-type heat pipe that can be mass-produced at low cost and a method for manufacturing the same.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, a plate-type heat pipe serving as a base of the present invention includes a corrugated bent middle plate that forms a side wall of a meandering pore in which a heat medium is enclosed, and front and rear surfaces of the middle plate. And a front plate joined so as to cover the intermediate plate.
Since the side walls of the pores are formed by press-bending a flat plate, the manufacturing cost is lower than that of cutting. In addition, by changing the height, width, and shape of the press die during the press bending process, pores having an arbitrary size and shape can be formed.
[0009]
In the present invention, the communication path of the meandering pores can be formed at the end portion of the intermediate plate by press punching. If the communication path is formed in the intermediate plate by press working, the turn portion of the meandering pore can be easily configured as compared with the case where electric discharge machining or the like is used.
[0010]
A plate-type heat pipe manufacturing method as a base of the present invention is a method for manufacturing a plate-type heat pipe having meandering pores in which a heat medium is enclosed, wherein communication paths are formed by press punching at both ends of an intermediate plate. The intermediate plate is bent into a wave shape, the front plate is bonded to the front and back surfaces of the intermediate plate so as to cover the intermediate plate, and the end of the laminated body of the intermediate plate and the front plate is connected to one end One of the pores formed by the front plate and the middle plate is crushed and sealed, and a heat medium is sealed from the remaining pores and sealed.
A plate-type meandering small-diameter heat pipe can be produced by a simple method, and mass production becomes possible.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, it demonstrates, referring drawings.
FIG. 1 is an exploded view showing the structure of a plate heat pipe according to an embodiment of the present invention. The top, bottom, left, and right in the text indicate the top, bottom, left, and right directions in the figure.
The plate heat pipe 1 has a laminated structure including an intermediate plate 3 and two front plates 5 and 7 sandwiching the intermediate plate 3. The middle plate 3 and the front plates 5 and 7 are made of a material such as aluminum having high thermal conductivity. In this example, the thickness of the middle plate 3 and the front plates 5 and 7 is 0.3 mm. In FIG. 1, the thin shape of the end portion of the intermediate plate 3 is not shown.
[0012]
The middle plate 3 is continuously bent in a rectangular wave shape. The side surface of the intermediate plate 3 has a shape in which U-shapes are alternately arranged in reverse. Both sides of the U-shape are the side walls of the pores of the plate heat pipe 1, and the middle side is the upper or lower wall of the pores.
[0013]
The shape of the end portion of the intermediate plate 3 and the bending method will be described in detail.
FIG. 2 is an enlarged perspective view showing an end portion of an intermediate plate according to an example of the plate heat pipe of the present invention.
The middle plate 3 is bent into a rectangular wave shape as described above. The middle plate 3 includes upper and lower surfaces 3a and 3a ′, a side surface 3b formed with a long cutout 15b, and a side surface 3c formed with a short cutout 15c. Both notches play a role of escape when both ends are pressed. The long notch 15b serves as a communication path for the heat medium (details will be described later).
[0014]
3A is a plan view showing a flat plate-like state before the middle plate of FIG. 2 is folded, and FIG. 3B is a side view of the folded middle plate.
The intermediate plate 3 is made from a flat plate 9 shown in FIG. The flat plate 9 has a plurality of fold lines (two-dot chain lines) 11 parallel to the length direction. The portion of the flat plate between the two fold lines 11 is the portion that forms the side walls and the upper and lower walls of the pores. At both ends of each row, short notches 15c and long notches 15b are alternately formed by punching with the row 13 having no notches interposed therebetween. Furthermore, the row | line | column in which the notch was formed has the short notch 15d and the long notch 15c formed in a pair at the both ends of a row | line | column. That is, in the row in which the long notch 15c is formed at one end, the short notch 15d is formed at the other end. The row 13 in which notches are not formed is straight at both ends.
[0015]
When the flat plate 9 is bent, it is pressed in a rectangular wave shape along the fold line 11 so that the rows 13 without notches are the upper and lower sides of the rectangle and the rows with the notches are the sides of the rectangle. Bend by bending. That is, the folding lines on both sides of the row 13 where no notch is formed are folded in a mountain when viewed from the front of the figure, and both sides of the row 13 where the next notch is not formed are folded in a valley. By repeating this, the flat plate 9 is bent into a rectangular wave shape with a side cross section in which the row 13 in which notches are formed is the upper and lower sides and the row in which the notches are formed is the side.
[0016]
FIG. 3B shows the side surface of the bent flat plate 9. The side on one side painted black in the figure is the side on which the long notch 15b is formed. As described above, the upper and lower sides of the rectangular portion are rows 13 in which notches are not formed, the black side is a row in which long notches 15b are formed, and the other sides are formed with short notches 15c. Column. The side where the long notch 15b is formed and the side where the short notch 15c is formed are alternately arranged across the side where the notch is not formed. In FIG. 3B, the row 13 in which notches are not formed corresponds to the upper and lower surfaces 3a and 3a ′ in FIG. 2, and the row in which long notches 15b are formed corresponds to the side surface 3b and is short. The row in which the notches 15c are formed corresponds to the side surface 3c.
[0017]
On the intermediate plate 3 manufactured as described above, the front plates 5 and 7 are joined from above and below by brazing to form a laminate.
4A and 4B are diagrams schematically showing the laminate, in which FIG. 4A is a plan sectional view, FIG. 4B is a front view, and FIG. 4C is a side sectional view.
As shown in FIG. 4C, the upper and lower surfaces 3 a and 3 a ′ of the bent middle plate 3 are in contact with the front plates 5 and 7. By this joining, a plurality of parallel pores 17 separated by the side surfaces 3 b and 3 c of the intermediate plate 3 are formed between the two front plates 5 and 7. As shown in FIG. 4 (A), the side wall of the pore 17 has a portion that is shortened by the formation of the long notch 15b and a portion that is elongated by the formation of the short notch 15b. Each notch is located alternately at one end of the laminate. In addition, each notch is positioned so that the long side wall and the short side wall are shifted one by one at both ends of the laminate.
[0018]
The laminate is pressed from both ends by a predetermined length of the pressing surface 19 (see FIGS. 4A and 4B). The press length is almost equal to the length of the short notch 15c from the end, and is shorter than the length of the long notch 15b. Since the long and short cutouts are formed on the side walls at both ends, the side walls that support the upper and lower walls do not exist for a certain length (short cutout length) from the end (see FIG. 2). It can be crushed relatively easily when it is pressed. After the press surface 19 is pressed, the ends of the press surface 19 are joined by laser welding.
[0019]
In this state, as shown in FIG. 4A, a space 21 is formed between the end of the side wall formed by the surface 3 b where the long notch is formed and the press surface 19. This space 21 is shifted by one row at both ends of the laminate, and serves as a communication path from one row of pores to the next row. The conduit of the heat medium formed from the pores formed in this way extends in the length direction of the laminate, and becomes a series of meandering pores that meander by alternately turning at both ends of the laminate. .
[0020]
At the time of pressing, one of the formed pores remains without being pressed. A heat medium such as water or butane is injected from the opening of the remaining pores. After the heat medium is injected, the pores are sealed by laser welding or the like, and a plate-type meandering pore heat pipe is produced.
[0021]
The plate-type meandering pore heat pipe formed by the above-mentioned method has a length of 200 mm, a width of 60 mm, and a thickness of 2 mm (including the thickness of the middle plate and the front plate of 0.3 mm). The size of the opening of the hole is 1.1 mm in height and 1.1 mm in width.
Note that the size of the opening of the pore can be changed by changing the height and width of the press die when the flat plate is bent by press working.
[0022]
FIGS. 5A and 5B are side views showing the bent shape of the intermediate plate according to another embodiment of the present invention.
The intermediate plate may be bent into a triangular wave shape as shown in FIG. 5A or a meandering shape as shown in FIG. Even in such a case, the top of the bent portion is joined to the front plates 3 and 5 by brazing or the like, and a laminated body of plate-type heat pipes is produced.
[0023]
【The invention's effect】
As is clear from the above description, in the heat pipe of the present invention, the side walls of the pores are formed by press bending a flat plate rather than extrusion molding or cutting, so that the heat pipe can be mass-produced at low cost. Furthermore, the turn part of the meandering pores can be efficiently formed by forming the communication path at the end of the intermediate plate by press punching.
[Brief description of the drawings]
FIG. 1 is an exploded view showing a structure of a plate heat pipe according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view showing an end portion of an intermediate plate according to an example of a plate heat pipe of the present invention.
3A is a plan view showing a flat plate-like state before the middle plate of FIG. 2 is bent, and FIG. 3B is a side view of the folded middle plate.
4A and 4B are diagrams schematically showing a laminate, in which FIG. 4A is a plan sectional view, FIG. 4B is a front view, and FIG. 4C is a side sectional view.
FIGS. 5A and 5B are side views showing a bent shape of an intermediate plate according to another embodiment of the present invention.
6A and 6B are diagrams showing a heat pipe manufacturing method disclosed in JP-A-7-63487, in which FIG. 6A is a sectional view and FIG. 6B is a partially broken plan view showing an internal structure. It is.
7A and 7B are diagrams showing a heat pipe manufacturing method disclosed in Japanese Patent Laid-Open No. 9-49692. FIG. 7A is a cross-sectional plan view for explaining the first step, and FIG. It is a plane sectional view for explaining the 2nd process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plate type heat pipe 3 Middle plate 5, 7 Surface plate 9 Flat plate 11 Bending line 13 Row 15 Notch 17 Pore 19 Press surface

Claims (2)

A corrugated intermediate plate that forms the side wall of the meandering pores in which the heat medium is enclosed;
A front plate joined to cover the middle plate on the front and back surfaces of the middle plate;
Comprising
The intermediate plate is bent to form a plurality of parallel pores,
A cutout is formed at the end of the intermediate plate, and the cutout serves as a communication path for the heat medium and constitutes a turn portion of the meandering pore.
The heat medium pipe formed from the pores formed in this way is a plate-type heat pipe that becomes a series of meandering pores that meander and turn alternately at both ends,
At both ends of the intermediate plate, short notches and long notches are alternately formed across rows in which notches are not formed,
The row in which the notches are formed has a pair of the short notch and the long notch formed at both ends of the row,
From both ends of the laminate of the intermediate plate and the front plate, a portion substantially equal to the length of the short notch is pressed, and the end of the pressed surface is joined,
The short notch and the long notch play a role of escape when pressing at both ends,
The plate-type heat pipe, wherein the long notch serves as a communication path for a heat medium . The plate-type heat pipe manufacturing method according to claim 1, which has meandering pores in which a heat medium is enclosed,
Form the short notch and the long notch at the end of the intermediate plate by press punching,
The long notches are formed so that the communication passage adjacent pores, by bending the intermediate plate in a wave shape to form a wall of a plurality of parallel pores,
A plurality of parallel pores are formed by joining the front plate so as to cover the middle plate on the front and back surfaces of the middle plate,
From both ends of the laminate of the intermediate plate and the front plate, pressing a portion substantially equal to the length of the short notch, and joining the end of the pressed surface,
Seal both ends of the joined intermediate plate and the front plate by crushing them, leaving one mouth of the pores formed by the front plate and the intermediate plate, and alternately turning at both ends. Without a series of meandering pores to meander,
A plate-type heat pipe manufacturing method, wherein a heat medium is sealed and sealed from the remaining pore opening.

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