JP3914905B2 - heatsink - Google Patents

Description

  The present invention relates to a heat sink (heat dissipating body) for dissipating heat from a heating element such as a semiconductor element such as an electronic device such as a personal computer, a hard disk device, and a mounting substrate, and the heat dissipating performance thereof is remarkably improved. .

Conventionally, as this kind of heat sink, an aluminum alloy block shape, an aluminum alloy block shape having a large number of heat radiation fins, and the like are widely used.
However, such a conventional heat sink has a problem that its surface area is small and the heat dissipation property that is proportional to the surface area is not sufficient. For this reason, when the amount of heat generated from the heating element increases, the heat sink must inevitably be increased in size, resulting in a disadvantage that the electronic device is increased in size. In addition, there is a disadvantage that a large cooling fan must be provided in order to improve heat dissipation.
JP 2002-280773 A JP 2001-24114 A Japanese Patent Laid-Open No. 11-45967

  Accordingly, an object of the present invention is to obtain a heat sink that has a large heat dissipation amount, is excellent in a heat dissipation effect, and can be downsized.

To solve this problem,
The invention according to claim 1 has a heat sink body and a substrate that is in thermal contact with the heat sink body,
The heat sink body is obtained by knitting a metal wire to form a knitted tape, winding the knitted tape into a preform, and compression molding the preform, and the metal wires are three-dimensionally entangled with each other. It is a heat sink characterized by comprising a compressive compression molding.

The invention according to claim 2 has a heat sink body and a cooling pipe that penetrates the heat sink body in a state of being in thermal contact with the heat sink body,
The heat sink body is obtained by knitting a metal wire to form a knitted tape, winding the knitted tape into a preform, and compression molding the preform, and the metal wires are three-dimensionally entangled with each other. It is a heat sink characterized by comprising a compressive compression molding.
The invention according to claim 3 is the heat sink according to claim 2, wherein the cooling pipe is a heat pipe.

The invention according to claim 4 has a heat sink body and a metal case surrounding the heat sink body in a state of being in thermal contact with the heat sink body,
In this metal case, two or more openings are formed, and gas flows through the heat sink body from one opening to another opening,
The heat sink body is obtained by knitting a metal wire to form a knitted tape, winding the knitted tape into a preform, and compression molding the preform, and the metal wires are three-dimensionally entangled with each other. It is a heat sink characterized by comprising a compressive compression molding.
The invention according to claim 5 is the heat sink according to claim 4, wherein gas is forced to flow from one opening to another opening.

  In the invention according to claim 1, since the heat sink body is porous, the surface area thereof is extremely large, and a gas such as air circulates in the heat sink body, so that the heat dissipation effect becomes extremely large. Can be realized.

Moreover, in the invention which concerns on Claim 2, since the heat | fever transmitted to a cooling pipe is transmitted to a heat sink main body and is radiated from a heat sink main body, the heat dissipation of a cooling pipe improves. In particular, if a heat pipe is used as the cooling pipe as in the invention of claim 3, the amount of heat transfer to the heat pipe itself can be increased.
In the inventions according to claims 4 and 5, in addition to heat radiation from the metal case, gas such as air is forced to flow through the voids in the porous and air-permeable heat sink body to dissipate heat. Is expensive.

FIG. 1 shows a first example of a heat sink according to claim 1. The heat sink in this example includes a heat sink body 1 and a substrate 2. The heat sink main body 1 has a rectangular parallelepiped shape, and a flat substrate 2 having a thickness of 1 to 5 mm made of a metal having good heat transfer properties such as aluminum and copper is mechanically bonded to one surface by a brazing agent 3. And thermally bonded.
This brazing agent 3 is preferably melted at a temperature of about 300 to 600 ° C., and it is preferable that a part of the melted brazing agent penetrates from the surface of the heat sink body 1 into the inside and solidifies. Heat from the substrate 2 is favorably conducted to the heat sink body 1.

The heat sink body 1 is formed by knitting a metal wire made of a metal having high thermal conductivity such as aluminum, copper, and silver to form a knitted tape. The knitted tape is wound to form a preform, and the preform is compression-molded. The obtained metal wire is composed of a porous compression molded product in which metal wires are entangled three-dimensionally.
This porous compression molded product has already been filed as a patent application by the present applicant, for example, as Japanese Patent Application No. 254968. Specifically, this porous compression-molded product is produced as follows.

First, the metal wire is knitted to form a knitted tape. There are a method in which a metal wire is sacked flat or a method in which a metal wire is circularly knitted into a cylindrical shape and then formed into a flat shape. The metal wire can be knitted using one or a plurality of metal wires, but is preferably knitted using one metal wire.
Next, the knitted tape is wound in the length direction to form a preform. Prior to this winding, it is desirable to form folds parallel to the width direction, preferably folds inclined in the width direction, on the knitting tape. Next, the preform is filled into a compression mold, and is compressed and molded with the width direction of the knitting tape as the pressing shaft.

  At the time of this compression molding, a compression mold having a columnar portion can be used, and a knitted tape can be wound around the columnar portion to form a preform, which can be compression molded. Moreover, the porous compression molding of arbitrary shapes can be shape | molded by changing the shape of a compression mold. Further, when the knitting tape is filled into the compression mold, the terminal portion of the knitting tape can be made at least one turn along the outer periphery of the preform. Furthermore, when filling the knitting tape into the compression mold, the terminal portion of the knitting tape that is the outside of the preform may be folded back and inserted into the inside or inside of the preform. In addition, as the compression mold, it is also possible to use one in which a concave portion or a convex portion is formed on at least one of the surfaces facing each other along the pressing shaft.

  In the porous compression molded product thus obtained, when the knitting tape is compressed in the tape width direction, the loop forming the stitches is extruded in the thickness direction, and adjacent portions are extruded. The loops are entangled with each other to form a strong bond. Due to the coupling of the loops, the porous compression molded product is less likely to be loosened or deformed regardless of the size, and can maintain a precise three-dimensional shape even when external pressure is applied. Further, there is no cut end of the wire rod on the surface of the compression molded product, and the surroundings are not damaged and the metal strip does not flow out.

Furthermore, since this porous compression molded product is entirely formed of a knitted tape obtained by knitting a metal wire, it is porous and has good air permeability. In addition, since the loops of the metal wire are entangled three-dimensionally and firmly bonded, they have omnidirectional elasticity.
In such a porous compression molded product, the metal wire is intricately entangled three-dimensionally, so that heat is quickly transmitted to the entire molded product. Moreover, since air flows into the space between the metal wires, heat is transferred between the surface of the metal wires and the air, and since the surface area of the wire in contact with the air is remarkably large, the heat dissipation performance is high.
For this reason, by using this porous compression molded product as the heat sink body 1, excellent heat dissipation performance is exhibited.

  FIG. 2 shows a second example of the heat sink according to claim 1. This example is the same as the first example except that the surface of the heat sink main body 1 opposite to the bonding surface of the substrate 2 is wavy and a large number of fins 1a are formed.

  In such a heat sink, a heating element such as a semiconductor element, a hard disk device, a mounting substrate, or the like is fixed to the surface of the substrate 2 by an appropriate fixing means such as screwing. Then, heat from the heating element is transmitted to the heat sink body 2 through the substrate 2 and is dissipated to the outside from the surface of the heat sink body 2.

In particular, since the heat sink body 2 is composed of the above-described porous compression molded product, it is porous and air permeable, so that the substantial surface area in contact with air is extremely large and has excellent heat dissipation performance. Demonstrate.
Further, in the heat sink of the second example, since the heat dissipating fins 1a are formed on the surface of the heat sink body 2, the surface area is further increased, and the heat dissipation performance is further improved.

  FIG. 3 shows a first example of a heat sink according to claim 2. The heat sink of this example includes a heat sink body 1 and a cooling pipe 4. The heat sink main body 1 has a round cylindrical shape, and a cooling pipe 4 made of a metal having good heat conductivity such as aluminum or copper is inserted into a hollow portion inside the heat sink main body 1. 1 is also mechanically and thermally bonded by a brazing agent. The heat sink body 1 is made of the porous compression molded product described above.

  FIG. 4 shows a second example of the heat sink according to claim 2. In this example, the heat sink body 1 has a rectangular parallelepiped shape, and two circular through holes are formed therein, and cooling pipes 4 and 4 are inserted into the through holes, respectively. It is joined.

In the heat sinks of these examples, heat transmitted to the cooling pipe 3 is transmitted to the heat sink body 1 and is radiated from the heat sink body 1. For this reason, the heat radiation area becomes much larger than that of a single cooling pipe, and high heat radiation performance is exhibited.
If a known heat pipe is used as the cooling pipe 4, the heat transfer amount of the heat sink body 2 becomes extremely high.

5 and 6 show an example of a heat sink according to claims 4 and 5. FIG. The heat sink of this example is composed of a heat sink body 1 and a metal case 5, and the metal case 5 has a shape surrounding the heat sink body 1.
The metal case 5 is a hollow rectangular parallelepiped made of a metal having good heat conductivity such as an aluminum alloy or copper, and a first opening 6 is formed on an upper wall thereof, and a second opening is formed on two opposite side walls. Second and third openings 7 and 8 are formed.

Further, a heat sink body 1 made of a porous compression molded product formed in a rectangular parallelepiped shape is inserted into the metal case 5 and mechanically and thermally joined to the metal case 5 with a brazing agent.
As shown in FIG. 6, a fan 9 for forced air blowing is attached to the upper wall of the metal case 5 where the first opening 6 is formed so as to face the first opening 6. Cooling air is forcibly blown to the heat sink body 1 inside through the opening 6. Further, a heating element 10 such as a hard disk device or a mounting board is attached to the upper wall.

In the heat sink having such a structure, the heat from the heating element 10 is transferred to the metal case 5, a part of the heat is radiated from the metal case 5, and most of the heat is transferred to the heat sink body 1 through the metal case 5. The air is forcibly transmitted from the first opening 6 to the air fed into the heat sink body 1. The air that has been deprived of heat and is heated is discharged to the outside through the second and third openings 7 and 8. For this reason, the amount of heat transfer from the heat sink body 1 to the air is larger than that of natural ventilation, and as a result, the heating element 10 is cooled well.
The fan 9 may not be directly attached to the metal case 5, but air from a fan provided at a position away from the metal case 5 may flow from the first opening 6.

The heat dissipation performance will be specifically described below.
・ Sample 1 (conventional product)
A rectangular parallelepiped heat sink having a thickness of 10 mm, a width of 45 mm, and a depth of 45 mm made of an aluminum alloy was prepared.
Table 1 shows the weight, surface area, and heat dissipation performance of the heat sink.

・ Sample 2 (conventional product)
A square groove having a width of 5 mm and a depth of 5 mm was formed on the upper surface of the heat sink of Sample 1 to form five heat dissipating fins to obtain a heat sink.
Table 1 shows the weight, surface area, and heat dissipation performance of the heat sink.

・ Sample 3
A rectangular heat sink body having a thickness of 10 mm, a width of 45 mm, a depth of 45 mm, and a density of 1.8 g / cm ³ using an aluminum wire having a diameter of 0.2 mm and forming a porous compression molded product by the above-described manufacturing method. Was made.
Table 1 shows the weight, surface area, and heat dissipation performance of the heat sink body.

  From the results in Table 1, the heat sink body made of the porous compression molded product used in the present invention is lighter and has a much larger surface area than conventional heat sinks of the same volume, such as aluminum alloy blocks. It turns out that it is excellent in performance.

  The heat sink of the present invention can be used as a heat sink for cooling a heating element such as a semiconductor element such as an electronic device such as a personal computer, a magnetic recording device, and a mounting board.

It is a perspective view which shows the example of the heat sink of this invention. It is a perspective view which shows the example of the heat sink of this invention. It is a perspective view which shows the example of the heat sink of this invention. It is a perspective view which shows the example of the heat sink of this invention. It is a perspective view which shows the example of the heat sink of this invention. It is sectional drawing which shows the example of the heat sink of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat sink main body, 2 ... Board | substrate, 4 ... Cooling pipe, 5 ... Metal case, 6 ... 1st opening part, 7 ... 2nd opening part, ...・ Third opening

Claims (5)

A heat sink body and a substrate in thermal contact with the heat sink body;
The heat sink body is obtained by knitting a metal wire to form a knitted tape, winding the knitted tape into a preform, and compression molding the preform, and the metal wires are three-dimensionally entangled with each other. A heat sink comprising a compressible compression molded product. A heat sink body and a cooling pipe that penetrates the heat sink body in a state of being in thermal contact,
The heat sink body is obtained by knitting a metal wire to form a knitted tape, winding the knitted tape into a preform, and compression molding the preform, and the metal wires are three-dimensionally entangled with each other. A heat sink comprising a compressible compression molded product.   The heat sink according to claim 2, wherein the cooling pipe is a heat pipe. A heat sink body and a metal case that surrounds the heat sink body in thermal contact with the heat sink body;
In this metal case, two or more openings are formed, and gas flows through the heat sink body from one opening to another opening,
The heat sink body is obtained by knitting a metal wire to form a knitted tape, winding the knitted tape into a preform, and compression molding the preform, and the metal wires are three-dimensionally entangled with each other. A heat sink comprising a compressible compression molded product.   The heat sink according to claim 4, wherein gas is forced to flow from one opening to another opening.

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