JPH10263779A - Manufacture of heat sink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for surely manufacturing a heat sink large in heat exchange area and firm in constitution. SOLUTION: Metallic fins 8 are squeezed in the thickness direction or in the width direction to reduce the thickness or the width, and projected parts 10 which are projected in the thickness direction or the width direction of the fins 8 and substantially continuous in the plane direction are formed. One end part of the fins 8 is projected in a cavity 50 and held with one end part of the projected parts 10 toward the cavity 50. The molten metal 13 of the material to form a base 7 is poured in the cavity 50, and the fins 8 are assembled in an erected condition relative to the base 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink for increasing a heat exchange area in various heat exchangers and heat transfer devices, and more particularly to a heat sink manufactured by a pressure casting method.

[0002]

2. Description of the Related Art In heat-related equipment such as heat pipes,
It is well known that a heat sink is provided to increase the heat exchange area by increasing the heat radiation area or heat absorption area.

One example is shown in FIGS. 9 and 10. FIG.
The heat sink 1 shown in FIG. 9 has a configuration in which a plurality of flat fin bodies 2 parallel to each other extend vertically upward from the upper surface of a flat base 3, and is extruded using, for example, an aluminum alloy as a material. It is manufactured by a molding method. Further, the heat sink 1 shown in FIG. 10 has a configuration in which the fin body 2 is formed in a cylindrical shape instead of a flat plate shape, and is manufactured by, for example, forging using a copper alloy as a material.

Here, the above-mentioned extrusion or forging is a method of integrally processing the fin main body 2 and the base 3 from a single material. Therefore, as shown in FIG. The fin body 2 to be obtained has a minimum thickness (t) of about 2 mm and a thickness (t) of 2 mm.
The height (h) of the fin main body 2 when the height is set to 20 mm is limited to about 20 mm at the maximum. Therefore, the ratio (C) between the thickness (t) and the height (h) of the fin body 2 in these manufacturing methods is expressed as C = h / t ≦ 20/2 = 10. Further, the pitch (p) between the fin bodies 2 is required to be at least 5 mm or more.

As described above, in the conventional heat sink 1 obtained by the above-described manufacturing method by extrusion molding or forging, the fin main body 2 cannot be formed thin and high, and is provided with respect to the surface area of the base 3. Since the number of fin bodies 2 (number of fins) was also small, a sufficient heat exchange area could not be obtained.

As a means for solving the above-mentioned problems, a heat sink employing a pressure casting method has been proposed, and this will be briefly described with reference to FIG. This type of heat sink 4 is configured such that a plurality of rolled plates formed in a predetermined shape in advance are held substantially in parallel with each other, and a molten metal is cast so as to integrally cast, for example, about 2 mm of each lower end of the rolled plates. Is pressure-cast and integrated with the flat base 5.

According to this pressure casting method, since a ready-made rolled plate is adopted as the fin body 6, it is possible to achieve both thinness and height in the fin body 6 and narrow the pitch of each fin body 6. As a result, the heat exchange area as the heat sink 4 can be made larger than that of the conventional heat sink.

[0008]

However, in this kind of heat sink 4, there is a possibility that the fin body 6 may be deformed so as to be bent from the base end thereof. This is because the load acting on the base end side of the fin body 6 increases in proportion to the height of the fin body 6, and the fin 6 itself is softened by the heat of the molten metal when the base 5 is cast. This seems to be the cause.

That is, in the prior art, a heat sink having a structure in which the fin body is thin and high and has sufficient strength has not been developed.

The present invention has been made in view of the above circumstances, and has as its object to provide a method capable of reliably manufacturing a heat sink having a large heat exchange area and a strong structure.

[0011]

Means for Solving the Problems and Action Therefor To achieve the above object, according to the first aspect of the present invention, a fin made of metal is crushed in the thickness direction or the thickness direction to reduce the thickness of the metal fin. Alternatively, the thickness is reduced, and a projection that projects in the thickness direction or the thickness direction of the fin and that is substantially continuous in the surface direction is formed. Then, one end of the projection is directed toward the cavity. Then, one end of the fin is projected and held inside the cavity,
From this state, a molten metal of the material forming the base is poured into the cavity, and the fins are assembled in an upright state with respect to the base.

Therefore, according to the first aspect of the present invention, first, the fins are crushed to be thin or thin, so that segregation and voids existing inside the fins are eliminated or reduced, and the fins themselves are reduced. Strength is improved.
In addition, the portion of the fin where the protrusion is provided is thicker than the other portions, so that the strength is locally increased. Further, since the projection is oriented in a direction standing upright with respect to the base, that is, in a height direction of the fin, the projection acts as a so-called reinforcing rib against deformation in a direction in which the fin is bent. Therefore, the heat sink has a strong structure.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram for explaining a step of reducing the thickness of a fin material in a manufacturing method according to the present invention. First, a flat rolled material 30 made of Al or an Al alloy is prepared as a fin material. In this specific example, in order to adopt the blanking process, the rolled material 30 has a size corresponding to the size of the fin to be formed.
It is assumed that it is as large as the width.

First, the rolled material 30 is attached to the outer shape cutting die 31, and is punched into a rectangle or a square. The outer shape removing die 31 has a configuration in which an upper die 32 includes a punch 33 and a movable stripper 34, and a lower die 35 includes a die 36 and a movable pad 37 (knockout 37) having a cushion. Therefore, immediately before being punched, the rolled material 30 is punched in a state where the inner and outer shapes are simultaneously pressed down by a strong force.

In this case, the rolled material 30 that has been punched out and taken out is compressed in the thickness direction by the punch 33 and the knockout 37, and has a thickness of 0.2 to 0.2 mm.
About 10% thinner. As described above, by compressing in the thickness direction, segregation and voids existing inside disappear or decrease, so that the strength of the rolled material 30 is improved.

Next, a projection is formed on the thinned rolled material 30. In this processing, as shown in FIG. 2, a die 39 having a concave portion 38 formed of a linear V groove on the upper surface is used.
And a V-bending die 41 formed by a punch 40 having a tip corresponding to the recess 38. That is, the rolled material 30 is laid on the upper surface of the die 39 so that the linearly extending concave portion 38 and the line of the edge of the rolled material 30 are orthogonal or parallel to each other, and the punch 40 is lowered from this state. Then, as shown in FIG. 3, the protruding portion 10 projecting in a V-shaped cross section is formed from the upper edge to the lower edge of one surface of the rolled material 30.

The protruding portion 10 is connected to each rolled material 30.
Three articles are formed every time. In that case, these projections 1
0 is a state that is parallel to each other and spaced at equal intervals. Thus, the fin 8 is completed.

Next, the fins 8 are assembled integrally with the base. As this means, for example, a pressure casting method can be used. More specifically, as shown in FIG.
The upper end of each of the plurality of fins 8 is moved to the upper mold 11 (movable mold 11).
To be held. In this case, the fins 8 are arranged in parallel with each other with the surfaces on which the protrusions 10 are formed being aligned in the same direction, and the lower ends of the fins 8 are fixed to the lower mold 12.
It is held in a state of protruding about 1 to 2 mm into the internal space of the (fixed mold 12). In addition, these fins 8 are held in a state where the protrusions 10 are oriented in the vertical direction in FIG. The pitch (p) between the fins 8 is set to 2 mm.

The bottom of the upper mold 11 and the bottom of the lower mold 12 are
Both of them form a flat surface, and the distance between the upper and lower surfaces is about 3 mm. Therefore, the projection size of each fin 8 described above is the insertion depth of the fin 8 into the base 7 described above. As described above, the cavity 50 having a shape substantially following the base 7 is formed by the upper mold 11 and the lower mold 12. Further, the lower die 12 is provided with a pressure plunger 14 configured to press a molten metal 13 of Cu or a Cu alloy, which is a material of the base 7, upward from below in FIG.

From the above state, the pressure plunger 14 is moved in the direction of the arrow toward the movable mold 11 as shown in FIG. In this case, about 1 to 2 mm of the lower end of each fin 8 is inserted into the molten metal 13.

When the lower end of the fin 8 contacts the molten metal 13 of Cu or Cu alloy, the surface of the fin 8 is melted because the melting point of Al or Al alloy is lower than the melting point of Cu or Cu alloy. When the materials of the molten metal 13 and the fins 8 solidify together, the base 7 and the fins 8 are integrally connected. Further, if a cooling / cleaning step or the like is performed as usual, the operation is completed. As a result, it is possible to obtain the heat sink 9 having almost no void defects in the base 7 and having no deformation of the base 7.

The heat sink will be described with reference to FIGS. 6 and 7. A plurality of fins 8 are attached to the upper surface of the base 7 in FIG.
The heat sink 9 is formed by the base 7 and the fins 8.
Is configured. The base 7 has a thickness of 3 m as an example.
It is a substantially square or rectangular plate of about m.

On the other hand, the fin 8 is a rectangular plate having a height (h) of 20 mm. On the front surface of these fins 8 in FIG. 6, a V-shaped protrusion 10 is formed from the upper edge to the lower edge. Further, the protrusions 10 are provided at three positions of the fins 8 at equal intervals in the diagonal left-right direction in FIG.

On the other hand, portions of each fin 8 other than the protruding portion 10 are formed as flat portions 20 having a flat surface. In this specific example, four fins 8 are provided at four locations. In addition, as an example, the thickness (t) of these flat portions 20 is 1.5 mm. Therefore, FIG.
As shown in the figure, the ratio (C) between the height (h) of the fin 8 and the thickness (t) of the flat portion 20 is C = h / t ≦ 20 /
It is expressed as 0.5 = 40.

Here, other combinations of the material of the base 7 and the material of the fin 8 include Al-Mg, Al-graphite, Al-carbon fiber and the like. It is preferable to select a material having as high a thermal conductivity as possible and so-called good castability from these materials. Further, the surface of the fin 8 may be plated with Zn, Sn, or the like, so that the compatibility with the molten metal forming the base 7 is improved.

Therefore, according to the heat sink 9 configured as described above, since the strength in the height direction of the fins 8 is supported by the projections 10, it is possible to reliably prevent the fins 8 from being bent and deformed. it can.
Since the fin 8 made of the rolled material 30 is attached to the base 7 by pressure casting, the fin 8 can be made thin and high, and the pitch (p) can be set narrow, so that the overall fin 8 can be formed. The heat exchange area increases. Therefore, a heat sink 9 having a strong structure and a large heat exchange area can be obtained.

In the heat sink 9, the protrusion 1
0 is not excessively close to the adjacent fins 8 side. For example, when air is caused to flow between the fins 8 by a cooling fan, the air flow smoothly flows, and therefore, is excellent in heat dissipation. Heat sink 9.

Next, another specific example of the heat sink according to the present invention will be described with reference to FIG. The example shown here is an example in which the projection 10 is replaced with a V-shaped groove and a cross-shaped one. In addition, since the heat sink shown here can be manufactured in substantially the same procedure as in the first specific example, differences in the configuration will be described.

A plurality of cross-shaped projections 10 are formed on the front surface of the fin 8 in FIG. Between these projections 10,
Although a small gap (flat portion) is present in the vertical direction in FIG. In addition, seven rows of the projections 10 are provided in the horizontal direction in FIG. Note that these projections 10
As an example of a method for forming the boss, embossing may be mentioned.

Therefore, in the heat sink having the above-described structure, the strength of the fins 8 is supported by the large number of protrusions 10 in the height direction. Deformation can be prevented beforehand.

In each of the above specific examples, a flat fin is illustrated. However, the present invention is not limited to the above specific example, and the shape of the fin may be, for example, a wavy curved thin plate. The material of the fin is not limited to a rolled material, but may be a material formed by cutting or a cylindrical shape formed by casting.

Further, the projections are not limited to those illustrated, but may have a rectangular cross section, for example, and may be provided on both sides of the fin. In addition to the examples described in the above specific examples, a coining process in which a material is strongly pressed inside a closed mold to form irregularities having a shape following the mold on the surface thereof may be employed.

[0033]

As is apparent from the above description, according to the first aspect of the present invention, the fins are crushed to reduce the plate thickness or thickness, and protrude in the thickness direction or the thickness direction. Forming a substantially continuous projection in the direction, and then, with one end of the projection facing the cavity, holding the base with one end of the fin protruding inside the cavity, and attaching the base to the cavity. Since the molten metal of the material to be formed is injected and the fins are assembled in an upright state with respect to the base, a heat sink in which the fins do not bend can be obtained, that is, a heat sink having a large heat exchange area and a strong structure can be obtained. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an outline punching die and a rolled material.

FIG. 2 is a cross-sectional view showing a step of forming a projection.

FIG. 3 is a perspective view showing a single fin.

FIG. 4 is a schematic diagram showing a state before pressurization in a step of assembling the fin to the base.

FIG. 5 is a schematic diagram showing a state during pressurization in the process.

FIG. 6 is a schematic view showing a completed heat sink.

FIG. 7 is a cross-sectional view showing the relationship between the thickness and the height of the fin in the heat sink.

FIG. 8 is a schematic view showing another specific example of the heat sink.

FIG. 9 is a schematic view showing a conventional heat sink.

FIG. 10 is a schematic view showing another example of a conventional heat sink.

FIG. 11 is a schematic diagram showing the relationship between the thickness and height of a fin in a conventional heat sink.

FIG. 12 is a cross-sectional view illustrating a heat sink manufactured by a pressure casting method.

[Explanation of symbols]

7 ... base, 8 ... fin, 9 ... heat sink, 1
0: Projection, 20: Flat, 30: Rolled material, 31
... Outer die, 50 ... Cavity.

Claims (1)

[Claims] 1. A fin made of metal is crushed in a thickness direction or a thickness direction thereof to reduce a plate thickness or a thickness, and protrudes in a thickness direction or a thickness direction of the fin and in a plane direction. A substantially continuous projection is formed, and then, with one end of the projection facing the cavity, one end of the fin is protruded and held inside the cavity. A method of manufacturing a heat sink, comprising: injecting a molten metal of a material for forming a fin, and assembling the fin upright with respect to a base.