JP2003240461A - Plate type heat pipe and mounting structure of the heat pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plate type heat pipe having an excellent cooling efficiency. <P>SOLUTION: In this plate type heat pipe, the portion of the surface of two surfaces of a container forming the plate type heat pipe 1 to which a heating element is thermally connected is formed flat, and the other portions are formed in irregular shapes, whereby since the portion to which the heating element is thermally connected is formed flat, a thermal resistance between the plate type heat pipe 1 and the heating element 4 is reduced and the cooling efficiency is increased, the same effect is also obtained when a flat plate 7 is disposed on the flat portion 3, and for those heat pipes in which columns are disposed in the container corresponding to the flat portion 3, the shape of the flat portion 3 is maintained satisfactorily, for those in which a material with a high thermal conductivity is used for the columns, a thermal resistance in the plate type heat pipe is lowered and the cooling efficiency is increased, and those in which a mesh material is used for the columns, working fluid is circulated satisfactorily to increase the cooling efficiency. <P>COPYRIGHT: (C)2003,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 for the plate-type heat pipe that can efficiently cool 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 FIGS. 8 and 9, the plate-type heat pipe 21 includes a container body 1
8 is a container 20 in which a lid 19 is joined to 8, and a working liquid (not shown) is sealed under reduced pressure. A surface 22 to which a heating element is thermally connected is formed in an uneven shape to enhance heat dissipation. ing. When the heating element is brought into contact with the surface 22 of the plate-shaped heat pipe 21 to which the heating element is thermally connected, the working liquid in that portion takes the latent heat of vaporization from the heating element to evaporate and the heating element is cooled. . The evaporated working fluid is cooled on the other surface (the surface that does not thermally connect the heating element) 26 to become a liquid phase, and returns to the inside of the surface to which the heating element is thermally connected.

[0003]

However, in this plate-type heat pipe 21, as shown in FIG. 9, the heating element 4 is heated on the surface 22 to which the uneven heating element is thermally connected. However, since the recess 5 does not come into contact with the heating element 4, the heat transfer area becomes small and high cooling efficiency cannot be obtained. An object of the present invention is to provide a plate heat pipe having excellent cooling efficiency and a mounting structure thereof.

[0004]

According to a first aspect of the present invention, in the two surfaces of a container forming a plate heat pipe, an outer surface for thermally connecting a heating element is a portion where the heating element is thermally connected. Is a flat plate, and the other part is formed in a concavo-convex shape.

A second aspect of the present invention is the plate heat pipe according to the first aspect, wherein a flat plate is joined to a flat portion to which the heating element is thermally connected.

According to a third aspect of the present invention, a column for holding the shape of the plate heat pipe is arranged inside the container corresponding to the flat portion of the plate heat pipe. Alternatively, it is the plate heat pipe described in 2.

The invention according to claim 4 is the above-mentioned claims 1 to 3.
According to another aspect of the present invention, there is provided a plate-type heat pipe mounting structure in which a heating element is thermally connected to a flat portion of the plate-type heat pipe directly or through a flat plate.

The invention according to claim 5 is the same as claims 1 to 3.
A heat sink is thermally connected to the plate heat pipe according to claim 4, wherein the plate heat pipe has a mounting structure.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The plate heat pipe of the present invention will be described below in detail with reference to the drawings. In the plate-type heat pipe 1 according to the first aspect of the present invention, as shown in FIGS. 1A and 1B, the heating element 4 of the uneven surface 2 of the plate-type heat pipe 1 is thermally connected. The portion 3 to be formed is flat and the other portion is formed to be uneven. In this plate-type heat pipe 1, since the portion 3 to which the heating element 4 is thermally connected is flat, the heat resistance between the heating element 4 and the plate-shaped heat pipe 1 is small and the heating element is efficiently cooled. In addition, the other portions are uneven and have a large surface area, so that they have excellent heat dissipation.

In the present invention, the shape of the unevenness is circular,
It is arbitrary such as a polygon. It is desirable to form a large number of small irregularities because the surface area becomes larger and the heat dissipation is improved.

As a method for forming the unevenness, a press molding method (embossing method or the like) is simple and recommended. In the press molding method, the inner surface is usually formed in an uneven shape,
It is necessary to consider the uneven shape of the inner surface so that the flow passage area of the hydraulic fluid can be appropriately maintained. Further, the strength of the plate heat pipe 1 can be improved by bringing the recess 5 into contact with another inner surface 6.

According to a second aspect of the present invention, there is provided a plate heat pipe,
As shown in FIGS. 2A and 2B, the flat portion 3 is provided with a flat plate 7 for adjusting the height of the heating element 4 or enhancing the flatness. The flat plate 7 also contributes to improving the strength of the plate heat pipe 1 by arranging the flat plate 7 across the surface 2 for thermally connecting the heating element.

A plate-type heat pipe according to a third aspect of the invention is
The columns are arranged inside the container corresponding to the flat portion of the flat plate heat pipe of the invention, and the strength of the flat plate heat pipe is enhanced. The pillar is shown in FIG.
The columnar columns 8, the corrugated columns 9, the trapezoidal columns 10, and the like as shown in (a) to (c) can be applied. If a material having a good thermal conductivity is used for the pillar, the heat resistance inside the plate heat pipe 1 is reduced and the cooling efficiency of the plate heat pipe 1 is improved. A mesh material such as wire mesh, sintered metal (porous material), metal wool, carbon fiber, ceramics fiber, glass fiber can be used for the pillar. The wire mesh, metal wool, carbon fiber and the like are preferably reinforced by compression and used. The mesh material has an effect of promoting the reflux of the working liquid, and when the mesh material is a good thermal conductor, it also reduces the thermal resistance, and is therefore a desirable material.

The plate-type heat pipe of the present invention is constructed by depressurizing and enclosing the working fluid in a container consisting of a container body and a lid body. The container body and the lid body are made by pressing a plate material such as an aluminum alloy plate. It is manufactured by punching or press forming. Concavities and convexities can be formed during the press molding. Welding method to join the container body and lid,
A brazing method, an adhesive method or the like can be applied. The unevenness may be formed on either surface of the plate heat pipe.

In the present invention, the material of the container is copper (C1020, C1100, C1200, etc.), aluminum (A1010, A1100, A5000 series, A6).
000 series, A7000 series, etc. can be used. It is desirable that the container body and the lid are made of the same material in terms of productivity and corrosion resistance.

As the working fluid, helium, methane, ammonia, acetone, water, naphthalene, sodium, mercury, alternative CFCs, hydrocarbons and the like can be used, and these are properly used depending on the operating temperature. 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.

According to the fourth aspect of the invention, as shown in FIG.
This is a mounting structure in which a heating element 4 is joined to a flat portion 3 to which the heating element of the plate heat pipe 1 is thermally connected. In this mounting structure, since the heating element 4 is thermally connected to the flat portion 3, the heat resistance between the heating element 4 and the plate heat pipe 1 is small and the cooling efficiency is excellent. Except for the portion to which the heating element 4 is thermally connected, the heat dissipation is excellent because it is uneven.

According to the invention described in claim 5, as shown in FIG.
In the mounting structure in which the heating element 4 is joined to the flat portion 3 to which the heating element of the plate heat pipe 1 is thermally connected, and the heat sink 13 is thermally connected to the other surface 12, the mounting structure shown in FIG. Excellent heat dissipation.

In the present invention, the columns are joined to the inner surface of the plate heat pipe, the heating element is thermally joined to the flat portion of the plate heat pipe, the flat plate is joined to the flat portion, and the flat surface of the plate heat pipe is joined. For thermal bonding of the heat sink, it is desirable to use metal bonding having excellent thermal conductivity or bonding via another metal. Ultrasonic welding, resistance heating welding, arc (TIG, MIG, plasma, laser) welding, FSW (Friction Stir Welding), etc. can be applied to the former, and silver brazing, copper brazing, tin brazing to the latter. , Low temperature soldering can be applied. It is also possible to use an adhesive having good thermal conductivity.

A heat transfer grease, a heat transfer sheet, a heat transfer resin, etc. are interposed between the flat portion 3 of the plate heat pipe 1 and the heating element 4 and between the flat plate 7 and the heating element 4. The thermal resistance between the plate heat pipe 1 and the heating element 4 is reduced, which is desirable.

In the mounting structure shown in FIG. 6, the heating element 4 is mounted on the circuit board 14, and the entire body is surrounded by the housing 15.

In the mounting structure shown in FIG. 7, the flat plate 7 is arranged on the flat portion 3 of the plate heat pipe (see FIG. 2), the heating element 4 is thermally connected thereto, and the heat sink is attached to the other surface 12. 13 is thermally connected. Here, the flat plate 7 is fastened to the plate heat pipe 1 with bolts 16.
Bolt 16 is nut 1 in the part without heat sink 13.
7, the inner surface of the plate-shaped heat pipe 1 is partially projected at a portion where the heat sink 13 is present, and a screw groove is engraved on the inner surface of the protruding portion.
It is concluded to 1. The gap between the plate heat pipe and the bolt is filled with a brazing material or the like to close it. In FIG. 7, 10 is a trapezoidal pillar made of a mesh material.

In the present invention, when the heat sink is cooled by the fan, the heat radiation characteristic is improved. It is desirable that the fan is integrally attached to the plate heat pipe because the fan can be easily assembled. A corrugated fin, a comb fin, a crimped fin, or the like is used for the heat sink.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples. (Example 1) A C1020 aluminum alloy plate having a thickness of 1.0 mm was press-molded to produce a container body 18 and a lid body 19. The bottom surface of the container body 18 was embossed in a concavo-convex shape except for the portion 3 for thermally connecting the heating element 4 during press molding. Next, the above-mentioned members are assembled by brazing, and the working fluid is sealed under reduced pressure in the container by a conventional method, and the plate heat pipe shown in FIG. 1 (thickness 8 mm, width 6
0 mm, length 140 mm) was produced.

C mounted on the circuit board 14 in the flat portion 3 to which the heating element of the plate heat pipe 1 is thermally connected
PU (heat generation amount 100 W) 4 was brazed, and corrugated fins 13 were brazed to the other surface 12 of the plate heat pipe 1. The CPU 4 and the circuit board 14 are entirely the housing 15
(See FIG. 6). In this state, the temperature distribution of the CPU 4 is measured. When the maximum temperature is less than 50 ° C., the cooling efficiency is extremely excellent (⊚), 50 ° C. or more and 60 ° C. or less is excellent (∘), and 60 ° C. is inferior (×). ) Was evaluated.

(Embodiment 2) The plate-shaped heat is manufactured in the same manner as in Embodiment 1 except that the trapezoidal column 10 (FIG. 3C) is arranged inside the container corresponding to the flat portion 3 of the plate-shaped heat pipe 1. The pipe 1 was manufactured and the cooling efficiency was evaluated by the same method as in Example 1. The trapezoidal column is made of C1020 aluminum alloy mesh material (80 μm # 120).
A stack of 0 sheets was used.

Example 3 The same method as in Example 1 except that a flat plate 7 having a thickness of 1.0 mm was brazed to the flat portion 3 of the plate heat pipe 1 and the CPU 4 was thermally connected thereto. Then, the plate heat pipe 1 shown in FIG. 2 was manufactured, and the cooling efficiency was evaluated by the same method as in Example 1.

(Comparative Example 1) The cooling efficiency was evaluated by the same method as in Example 1 except that the CPU 4 was brazed to the conventional plate heat pipe 21 shown in FIG. 8 as shown in FIG. All the brazings were performed using BAg-8 as the brazing material. The results are shown in Table 1.

[0029]

[Table 1]

As is clear from Table 1, in Examples 1 to 3 of the present invention, the CPU was cooled well. In particular,
The cooling efficiency was extremely excellent in the case where the columns were arranged inside the container corresponding to the flat portion of the plate heat pipe (Example 2). On the other hand, in Comparative Example 1, since the CPU was thermally connected to the unevenness forming portion of the plate heat pipe, the thermal resistance between the CPU and the plate heat pipe increased, and the CPU was not cooled sufficiently.

[0031]

As described above, in the plate type heat pipe of the present invention, of the two surfaces of the container forming the plate type heat pipe, the surface that thermally connects the heating element is the one where the heating element is thermally connected. Since the portion connected to is formed flat and the other portions are formed in a concavo-convex shape, the thermal resistance between the plate heat pipe and the heating element is small and the cooling efficiency is excellent. The same effect can be obtained in a plate heat pipe in which a flat plate is arranged in the flat portion for adjusting the height of the heating element or increasing the flatness. The shape of the flat portion of the plate-shaped heat pipe, in which the pillars are arranged inside the container corresponding to the flat portion, is maintained well. In addition, if a good thermal conductive material is used for the pillar, the thermal resistance inside the plate heat pipe is reduced,
Further, if a mesh material is used, the working fluid is satisfactorily refluxed and the cooling efficiency is improved. The plate heat pipe of the present invention has a mounting structure in which a heating element is thermally connected to a flat portion or a flat plate portion on which the heating element is thermally connected, and a heat sink is thermally connected to the heat pipe. By doing so, high cooling efficiency can be obtained. Therefore, it has a remarkable industrial effect.

[Brief description of drawings]

FIG. 1A is a perspective view showing a first embodiment of a plate heat pipe of the present invention, and FIG. 1B is a sectional view taken along line AA of FIG.

FIG. 2A is a perspective view showing a second embodiment of the plate heat pipe of the present invention, and FIG. 2B is a sectional view taken along line AA of FIG.

3 (a) to 3 (c) are explanatory views of struts arranged inside the container corresponding to the flat portion of the plate heat pipe of the present invention.

FIG. 4 is a perspective view showing a first embodiment of a mounting structure of the present invention.

FIG. 5 is a perspective view showing a second embodiment of the mounting structure of the present invention.

FIG. 6 is a perspective view showing a third embodiment of the mounting structure of the present invention.

FIG. 7 is a perspective view showing a fourth embodiment of the mounting structure of the present invention.

FIG. 8 is a perspective view of a conventional plate heat pipe.

FIG. 9 is a partial vertical cross-sectional view showing a state where a heating element is thermally connected to a conventional plate heat pipe.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Plate heat pipe of the present invention 2 Surface for thermally connecting heating elements of plate heat pipe 3 Flat portion to which heating elements are thermally connected 4 Heating element (CPU) 5 Heating element for plate heating pipe Concave portion of surface to be thermally connected 6 Other inner surface of plate-type heat pipe (non-heater side inner surface) 7 Flat plate 8 Cylindrical column 9 Wavy column 10 Trapezoidal column 11 Projection part 12 with screw groove engraved 13 heat sink 14 circuit board 15 housing 16 bolt 17 nut 18 container body 19 lid 20 container 21 conventional plate type heat pipe 22 conventional plate type heat pipe heating element The surface to which the heat sink is thermally connected 26 The surface to which the heat sink of the conventional plate heat pipe is thermally connected

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E322 AA01 AA11 DB08 DB10                 5F036 AA01 BA06 BA23 BB01 BB21                       BB60 BC01 BC06

Claims (5)

[Claims] 1. Among two surfaces of a container constituting a plate-type heat pipe, a surface to which a heating element is thermally connected is formed flat at a portion to which the heating element is thermally connected, and the other portion is A plate heat pipe characterized by being formed in an uneven shape. 2. A flat plate is joined to a flat portion to which the heating element is thermally connected.
The plate heat pipe described. 3. The plate according to claim 1, wherein a column for holding the shape of the plate heat pipe is arranged inside a container corresponding to a flat portion of the plate heat pipe. Type heat pipe. 4. The plate heat pipe according to claim 1, wherein a heating element is thermally connected to a flat portion of the plate heat pipe according to any one of claims 1 to 3 directly or through a flat plate. Implementation structure of. 5. The mounting structure for a plate heat pipe according to claim 4, wherein a heat sink is thermally connected to the plate heat pipe according to any one of claims 1 to 3.