JP2003322484A - Plate type heat pipe and structure for mounting the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight plate type heat pipe with a small number of parts and excellent productivity. <P>SOLUTION: In the plate type heat pipe having a flat container 2 as a main component with a working liquid sealed in an evacuated condition, the flat container 2 is formed by forming a flat cylindrical body 6 formed by folding one plate 3 and having a hollow strut 1 inside thereof, and pressing both open ends of the flat cylindrical body 6 in the thickness direction to seal the cylindrical body. Since the flat container 2 is formed by folding one plate 3, the number of parts is small, and the productivity is excellent. The hollow strut 1 provided in the flat container 2 prevents the container from being dent by the external pressure, and improves the cooling characteristic. The strut 1 is hollow, and the plate type heat pipe is lightweight. The working liquid is excellently circulated by folding the hollow strut 1 in a fine manner to form a wick, resulting in a good cooling characteristic. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component (CPU, semiconductor chip, etc.) and an optical component (LD) mounted in high density.
Etc.) and a mounting structure thereof suitable for cooling a heating element such as.

[0002]

2. Description of the Related Art A plate-type heat pipe is widely used as a heat pipe for cooling a heating element such as a high-density mounted electronic component or optical component in view of space. As shown in FIG. 11 (a), the plate type heat pipe is a container body 2
Flat container 2 consisting of two parts in which a lid 22 is joined to 1
3. A working fluid (not shown) is sealed under reduced pressure in 3.
When a heating element (not shown) is thermally joined to one of the two surfaces of the flat container 23, the working fluid in that portion deprives the latent heat of vaporization from the heating element to evaporate, and the evaporated working fluid is the other. The surface side is cooled and becomes a liquid phase, and returns to the one surface side where the heating element is joined. The heating element is cooled by repeating the evaporation and condensation of the working fluid.

By the way, in the plate heat pipe, when the working fluid is sealed under reduced pressure, the surface of the flat container 23 may be dented by external pressure, and this dent reduces the thermal bonding property with the heating element or the heat sink. Good cooling characteristics may not be obtained. Therefore, in the plate heat pipe, as shown in FIG. 11B, a separately prepared block 24 is provided inside the flat container 23 to prevent the depression due to the external pressure.

[0004]

However, the flat container is difficult to manufacture because the container body, the lid and the block are joined to each other, and since the number of parts is large, it takes time to manage them. Therefore, the productivity was poor, and the increase in weight due to the block was a problem. The purpose of the present invention is to
An object of the present invention is to provide a plate heat pipe having a small number of parts, excellent in productivity, and lightweight, and a mounting structure thereof.

[0005]

According to a first aspect of the present invention, in a plate-type heat pipe whose main part is a flat container in which hydraulic fluid is sealed under reduced pressure, the flat container is composed of a single plate material. Is a plate-type heat pipe.

According to a second aspect of the present invention, in a plate-type heat pipe whose main part is a flat container in which hydraulic fluid is sealed under a reduced pressure, the flat container is a flat tube having a hollow column formed by bending a single plate material. It is a plate-type heat pipe characterized in that a flat body is formed, and both open ends of the flat tubular body are pressed against each other in the thickness direction and sealed.

A third aspect of the present invention is the plate heat pipe according to the second aspect, wherein a wick is formed on the hollow support column by finely bending the hollow support column.

According to a fourth aspect of the present invention, a heating element is thermally joined to one of the two surfaces of the flat container according to the first to third aspects and a heat sink is thermally joined to the other surface. It is a characteristic plate-type heat pipe mounting structure.

According to a fifth aspect of the present invention, the circuit board or the heat sink on which the heating element is mounted is fixed to the flat container with bolts and thermally joined to the flat container. It is a mounting structure of.

According to a sixth aspect of the present invention, there is provided a plate-type heat pipe mounting structure according to the fourth or fifth aspect, further comprising a fan for cooling the heat sink.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The plate heat pipe of the present invention is, as shown in FIG. 1, a flat container 2 having hollow struts 1 therein, in which a working fluid (not shown) is vacuum-sealed.
The flat container 2 is formed by bending one plate material. In all the drawings for explaining the present invention, components having the same function are designated by the same reference numeral, and the repeated description thereof will be omitted.

The method of manufacturing the plate heat pipe of the present invention will be specifically described below with reference to FIGS. 2 (a), 2 (b) and 3 (a)-(c). The left and right ends of the plate material 3 (FIG. 2 (a)) cut out according to the flat container development view are bent inward along the alternate long and short dash line and outwardly curved along the dotted line,
The hollow columns 1 are formed on both sides of the plate member 3 (see FIG. 2).
(B)). In FIG. 2 (a), 4 is a window that serves as a passage for the working fluid or the working fluid vapor. Next, the central portion of the plate member 3 is bent inward along the alternate long and short dash line to position the two hollow columns 1 back to back, and the joints 5 are brazed to form the flat cylindrical body 6 (see FIG. )). Next, both end portions of the flat tubular body 6 are pressed against each other in the thickness direction over the entire width, and the pressed contact portion is sealed by brazing to form the flat container 2 (FIG. 3).
(B)). In FIG. 3B, reference numeral 18 is a pressure-welded portion after brazing. Next, a hydraulic fluid (not shown) is injected through a hydraulic fluid injection hole 7 provided by cutting out a corner portion of the flat container 2, and then,
If necessary, the interior of the flat container 2 is depressurized to reduce the pressure, and finally the injection hole 7 is filled with a brazing material and sealed (Fig. 3).
(C)).

The plate-type heat pipe shown in FIG. 4 is formed by bending the flange portions 8 on both sides of the flat container 2, and the flange portions 8 can be used for fixing a heating element or fins.

According to the third aspect of the invention, as shown in FIG.
This is a plate-type heat pipe in which the wick 9 is formed by finely bending the portion of the hollow pillar 2 that serves as the vertical wall. The shape of the wick is arbitrary such as the convex shape shown in FIG. 6 (a) or the wavy shape shown in FIG. 6 (b), but if the acute angle portion 10 is formed on the convex wick or the wavy wick, the portion will be formed. At 10, a capillary force is generated in the hydraulic fluid to promote the reflux of the hydraulic fluid.

The plate-type heat pipe shown in FIG. 7 is a plate-type heat pipe in which a wick 9 is formed in the bottom wall of the hollow column 2. The shape of the wick 9 is shown in FIGS.
, Which are the same as those shown in FIGS. 6A and 6B.

Next, FIG. 9 shows an example of the mounting structure of the plate heat pipe of the present invention. Here, a plate-type heat pipe having the collar portion 8 shown in FIG. 4 was used. On one of the two surfaces of the flat container 2, the C mounted on the circuit board 11
The PU 12 is brazed and the fins 13 are brazed to the other surface. The circuit board 11 and the fins 13 are bolts 14 and nuts 15 on the flange portions 8 at both end portions of the flat container 2.
It is fixed by. The flat container 2 has an annular frame 16
Protected by.

Another example of the mounting structure of the plate-type heat pipe of the present invention is shown in FIG. In this mounting structure, the bolt 14 penetrates through the flat container 2 and the circuit board 11 and the fins 13
And are fixed. The gap between the flat container 2 and the bolt 14 is filled with a brazing material or the like and is hermetically sealed. A collarless heat pipe can be used here.

In the present invention, when the heat sink mounted on the plate heat pipe is cooled by the fan, the heat dissipation characteristic is improved. It is desirable that the fan is integrally attached to the plate-type heat pipe so that the assembly does not take time and effort. A corrugated fin, a comb fin, a crimped fin, or the like is used for the heat sink.

In the present invention, the bending of the plate 3 and the molding of the wick 9 are conveniently performed by using a press machine.
The flat cylindrical body 6 is formed by bending the plate member 3 and then bending the plate member 3 back-to-back portion 5a of the hollow strut 1 and abutting portions 5b at both ends of the plate member 3.
It can be easily manufactured by joining The back-to-back portion 5a of the hollow strut 1 may be joined only at its upper end portion 17 (see FIG. 3A).

In the present invention, the above-mentioned respective parts are joined by
Metal bonding having excellent thermal conductivity or bonding via another metal is desirable. The former uses ultrasonic welding, resistance heating welding,
Arc (TIG, MIG, plasma, laser) welding method, FSW (Friction Stir Welding), etc. can be applied,
Silver brazing, copper brazing, tin brazing, low temperature soldering, etc. can be applied to the latter. It is also possible to use an adhesive having good thermal conductivity. The shape of the flat container will be more stable if the hollow columns and the inner surface of the flat container are joined. In that case, the joining method is also useful.

In the present invention, if a material having a high heat conductivity is used for the plate member 3, heat conduction and heat dissipation will be excellent,
Further, the hollow support columns 1 promote heat transfer in the plate-like container, and the cooling efficiency is improved. Examples of the material having good thermal conductivity include copper (C1020, C1100, C1200, etc.), aluminum (A1010, A1100, A5000 series, A6).
000 series, A7000 series, etc. are recommended.

In the present invention, the working fluid is helium,
Methane, ammonia, acetone, water, naphthalene, sodium, mercury, CFC substitute, hydrocarbon, etc. can be used,
These are selected according to the operating temperature. When the wick is formed, the amount of the working fluid enclosed is preferably such that most of the working fluid is retained in the wick by capillary force, and the working fluid works most effectively in this amount.

In the present invention, it is desirable to interpose a heat-conducting grease, a heat-conducting sheet, a heat-conducting resin or the like between the plate-type heat pipe and the heating element because the thermal resistance between the two decreases.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples. (Example 1) Plate type heat pipe shown in FIG. 4 (thickness 8 m
m, width 60 mm (excluding flange), length 140 mm) were manufactured. That is, from a C1020 aluminum alloy plate having a thickness of 1.0 mm, a plate material having the same shape as the development view of the flat container was punched by a press machine, and this plate material was cut as shown in FIG.
A plate heat pipe was processed according to the manufacturing process shown in (c).

A CPU (heat generation amount: 100 W) mounted on a circuit board was brought into contact with one surface of the plate heat pipe, and a corrugated fin was brazed to the other surface. The circuit board and the corrugated fins are fixed by bolts and nuts as shown in FIG. 9, and the CPU and the circuit board are wholly annular frame 1
Covered with 6. In this state, the temperature distribution of the CPU was measured to investigate the cooling characteristics of the plate heat pipe. CP
It was evaluated that when the maximum temperature of U is less than 50 ° C, the cooling efficiency is extremely excellent (⊚), when it is 50 ° C or more and 60 ° C or less, it is excellent (◯), and when it exceeds 60 ° C, it is poor (x).

(Example 2) FIG. 6 or FIG.
A plate-type heat pipe was manufactured by the same method as in Example 1 except that the wick shown in 1 was formed, and its cooling characteristics were examined and evaluated by the same method as in Example 1.

(Comparative Example 1) A plate heat pipe was manufactured in the same manner as in Example 1 except that the CPU was brazed to the conventional plate heat pipe shown in FIG. 11B as shown in FIG. Was manufactured, and its cooling characteristics were examined and evaluated by the same method as in Example 1. All of the above brazing is BA
It was carried out using g-8. The results are shown in Table 1. The number of parts, productivity, and weight of the plate heat pipe are also shown. Productivity is
Extremely excellent is ◎, excellent is ○, inferior is ×
Indicated by.

[0028]

[Table 1]

As is clear from Table 1, N of the present invention example
o. Nos. 1 to 3 were excellent in cooling characteristics, and particularly Example 2 in which the wick was formed on the column was extremely excellent in cooling characteristics. Further, the plate heat pipe of the example of the present invention has a small number of parts and a small number of times of brazing, so that it is excellent in productivity, and further, the column is hollow and therefore lightweight. In particular, Example 1 in which no wick was formed was excellent in productivity. On the other hand, Comparative Example 1 was inferior in productivity due to the large number of parts, and was heavy because the block was used for preventing the depression.

[0030]

As described above, the plate heat pipe of the present invention has a small number of parts and is excellent in productivity because the flat container is composed of one plate material. In the flat container, the hollow columns are provided so that the depression due to the external pressure is prevented and the cooling characteristic is improved. The columns are hollow and therefore lightweight. By finely bending the hollow pillars to form a wick, the working fluid is satisfactorily refluxed and the cooling characteristics are further improved. In the plate heat pipe of the present invention, a heat generating element is thermally bonded to one surface of the plate container and a heat sink is thermally bonded to the other surface thereof to obtain high cooling characteristics. Therefore, it has a remarkable industrial effect.

[Brief description of drawings]

FIG. 1 is a plan view, an AA sectional view, and a side view showing a first embodiment of a plate heat pipe of the present invention.

[FIG. 2] Manufacturing process of plate heat pipe of the present invention (first half)
In the explanatory view, (a) is a plan view of the plate material cut out in accordance with the development view of the flat container, and (b) is a state in which the left and right end portions of the plate material are bent to form hollow columns on both sides of the plate material. It is a top view and an AA sectional view.

FIG. 3 is a manufacturing process (second half) of the plate heat pipe of the present invention.
In the explanatory diagram, (a) is a plan view of the flat cylindrical body, AA cross-sectional view, side view, (b) is a side view of the flat container, and (c) is a plan view of a method for vacuum-sealing the working fluid in the flat container. It is a figure.

FIG. 4 is a plan view and an AA cross-sectional view showing a second embodiment of the plate heat pipe of the present invention.

FIG. 5 is an explanatory plan view of a plate material of a wick portion showing a third embodiment of the plate heat pipe of the present invention.

6A and 6B are enlarged explanatory views of the wick portion shown in FIG.

FIG. 7 is an explanatory plan view of a plate material of a wick portion showing a plate heat pipe according to a fourth embodiment of the present invention.

8A and 8B are enlarged explanatory views of the wick portion shown in FIG.

FIG. 9 is a cross-sectional explanatory view showing an example of the mounting structure of the present invention.

FIG. 10 is a cross-sectional explanatory view showing another example of the mounting structure of the present invention.

FIG. 11 is a cross-sectional view of a conventional plate heat pipe (a).
Is a block without a block, and (b) is a block.

[Explanation of symbols]

1 hollow pillar 2 flat container 3 Plates cut out according to the development view of the flat container 4 Windows that serve as passages for hydraulic fluid or hydraulic fluid 5a Back-to-back seam of hollow columns 5b Butt parts at both ends of plate 6 flat cylinder 7 Hydraulic fluid injection hole provided by cutting out the corner of the flat container 8 Collars formed on both sides of the flat container 9 wicks 10 wick formed sharp corners 11 circuit board 12 CPU (heating element) 13 fins 14 Volts 15 nuts 16 Ring frame that protects flat containers 17 Top part 18 Pressure welding part after brazing 21 container body 22 Lid 23 Conventional flat container 24 blocks

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F28D 15/02 106 F28D 15/02 106G H01L 23/467 H01L 23/46 C F term (reference) 5F036 AA01 BA04 BA06 BA24 BB60 BC03

Claims (6)

[Claims] 1. A plate heat pipe having a flat container in which a working fluid is sealed under reduced pressure as a main part, wherein the flat container is composed of a single plate material. 2. A plate-type heat pipe comprising, as a main part, a flat container in which a working fluid is sealed under reduced pressure, wherein the flat container is formed by bending a single plate material to form a flat cylindrical body having hollow columns therein. A plate-type heat pipe, characterized in that both open ends of the flat tubular body are pressed against each other in the thickness direction and sealed. 3. The plate heat pipe according to claim 2, wherein a wick is formed on the hollow support column by finely bending the hollow support column. 4. A plate mold characterized in that a heating element is thermally joined to one of the two surfaces of the flat container according to claim 1 and a heat sink is thermally joined to the other surface. Heat pipe mounting structure. 5. The mounting structure for a plate-type heat pipe according to claim 4, wherein a circuit board or a heat sink on which the heating element is mounted is fixed to the flat container by a bolt and thermally joined thereto. 6. The fan according to claim 4, further comprising a fan for cooling the heat sink.
Mounting structure of the plate heat pipe described.