JPH08130274A - Heat sink - Google Patents

Abstract

PURPOSE: To obtain a large heat sink having enhanced performance at low cost. CONSTITUTION: The heat sink 10 comprises fins 12 having one ends fixed to a substrate 11. The fin 12 is made of a corrugated plate produced by bending a thin aluminum plate perpendicularly at a short pitch. The corrugated plate is brazed or welded, at the bent end plate part on one side thereof, to the substrate 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink using aluminum used for cooling semiconductor devices and the like.

[0002]

2. Description of the Related Art Thyristors, transistors or power I
Since a semiconductor such as C generates heat when operated, it is necessary to dissipate the heat. Therefore, a heat sink is used. The heat sink is usually composed of a substrate on which a semiconductor is fixed, and fins attached to the substrate. Plate fins in which a large number of plates are arranged in parallel or a large number of pins are erected at regular intervals on the fins. There is a pin fin. Pin fins have extremely good cooling efficiency,
Since a large heat sink having a pin fin structure is extremely expensive, plate fins are usually used. An example of the plate fin is shown in FIG. 5, which has a substrate 50 made of an aluminum clad plate and an aluminum fin 51 standing on the substrate 50 as shown in the figure. In the production of fins, it is troublesome to fabricate a large number of plates side by side, and further, since strength is weak if the plates are not connected in the middle, the vertical plates 52 normally arranged side by side at a constant pitch, A fin 5 having a ceiling plate 53 and a connecting plate 54 that connect the vertical plate 52 to the ceiling and the middle, respectively.
1 is manufactured by extrusion molding, and is brazed on the substrate 50.

[0003]

However, there is a problem that the cost of extrusion molding is relatively high. Furthermore, if the base end portion of the vertical plate 52 and the substrate 50 are not joined sufficiently, the cooling efficiency will drop, so it is necessary to perform sufficient brazing. Further, it is preferable to form small holes in the plate portion in order to increase the surface area, but it is difficult to form small holes in the case of extrusion processing. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat sink in which a large-sized heat sink can be manufactured at low cost and which has improved performance over conventional heat sinks.

[0004]

A method according to the above-mentioned object.
The heat sink described in claim 1 is a heat sink having a substrate and a fin whose one end is attached to the substrate, wherein the fin is a corrugated plate obtained by bending a thin aluminum plate at a right angle at a short pitch. The bent end plate portion on one side of the corrugated plate is joined by brazing or welding. The heat sink according to a second aspect is the heat sink according to the first aspect, wherein a large number of small holes are formed in the long plate portion of the corrugated plate at an opening ratio of 5 to 15%. The heat sink according to claim 3 is the heat sink according to claim 1 or 2, wherein the corrugated plate has a thickness of about 0.3 to 0.8 mm, and the corrugated plate has a bending pitch of 3 to 5 mm.
The long plate portion of the corrugated plate has a length of 50 to 80 mm.

[0005]

In the heat sink according to claims 1 to 3,
A corrugated plate obtained by bending a thin aluminum plate at a short pitch at a right angle is used as the fin, and a bent end plate portion on one side of the corrugated plate is joined to the substrate. Therefore, since the relatively wide bent end plate part is joined to the substrate, it has sufficient thermal conductivity even if there is a partial defect in the brazing, and therefore welding (eg spot welding or seam welding) The bent end plate portion of the corrugated plate and the substrate can be joined together, which improves productivity. And when one side of the bent end plate of the corrugated plate is joined to the substrate, each fin becomes a gate shape,
Strength is improved. Particularly, in the heat sink according to the second aspect, since a large number of small holes are formed in the long plate portion of the corrugated plate with an opening ratio of 5 to 15%, the surface area is improved and the cooling efficiency is improved. . In this case, this small hole can be formed extremely easily by punching the aluminum plate before corrugating. Further, in the heat sink according to claim 3, since the thickness of the corrugated plate is about 0.3 to 0.8 mm and the bending pitch of the corrugated plate is 3 to 5 mm, it is easy to bend and form the long plate of the corrugated plate. The length of the part is 50
Since it is set to -80 mm, the weight can be reduced and the cooling efficiency can be improved. That is, when the bending pitch of the corrugated plate is small, there is a drawback that the ventilation resistance increases and the corrugating process is difficult, and when the bending pitch of the corrugated plate is wide, the cooling efficiency decreases.
When the corrugated plate has a large thickness, corrugating becomes difficult, and when the corrugated plate has a small thickness, the heat conduction area decreases and the heat transfer efficiency decreases. Next, it is difficult to secure a sufficient heat dissipation area when the long plate part of the corrugated plate is short, and when the long plate part of the corrugated plate is long, the heat is not transferred to the end. As a result, the heat transfer efficiency with respect to the weight decreases.

[0006]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. 1 is a front view of a heat sink according to an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a front view showing the same manufacturing process, and FIG. 4 is an explanatory view of a heat sink according to another embodiment. Is.

As shown in FIGS. 1 and 2, a heat sink 10 according to an embodiment of the present invention comprises an aluminum substrate 11
And an aluminum corrugated board 12. Board 1
Reference numeral 1 is a clad plate having a plate thickness t of about 8 to 10 mm in which a low melting point silicon aluminum alloy 14 is laminated on the surface of a pure aluminum plate 13.

The corrugated plate 12 has a thickness of 0.3 to
An aluminum plate having a width of about 0.8 mm and a width W of about 100 to 200 mm, and the height h of the long plate portion 15 is set to 50 to 80 mm,
The bending pitch p is set to 3 to 5 mm, and the zigzag shape is bent at a right angle to form a corrugated shape.

Then, as shown in FIG. 3, the corrugated plate 12 is placed on the substrate 11 and pressed by the pressing member 17 having the pressing teeth 16 which are fitted in the valleys of the corrugated plate 12 to be vacuum or inactive. The corrugated plate 1 is heated to a temperature lower than the melting point of aluminum and higher than the melting point of the silicon-aluminum alloy 14 while maintaining the gas atmosphere.
2 is brazed to the substrate 11. In this case, the pressing member 17 is slightly raised from the valley bottom 18 of the corrugated plate 12 so that the whole can be heated to be brazed, and then the pressing member 17 is lowered to set the valley bottom 18 of the corrugated plate 12 to the substrate. Alternatively, the pressing member 17 may be lifted at the time when it is pressed against 11 and brazing of the bent end portion is completed to some extent. Then, the whole is cooled and the heat sink 10 is completed.

In the above embodiment, the corrugated board 1 is further added.
The second long plate portion 15 may be provided with a small hole 19 as shown in FIG. 4, which further increases the heat radiation area. Here, if a large number of small holes are provided, the heat dissipation area increases, but the effective heat conduction area also flows through the cross-section of the corrugated plate 12, so a small hole with a diameter of 1 to 3 mm is about 5 to 15%. If the aperture ratio is set to, the overall heat dissipation efficiency is improved. Tables 1 and 2 show the conventional heat sink 55 shown in FIG.
It shows the properties of various heat sinks to which the embodiment of the present invention is applied.

[0011]

[Table 1]

[0012]

[Table 2]

As is clear from Table 1, the heat sink according to one embodiment of the invention has better overall cooling efficiency,
Furthermore, it can be seen that the weight is also reduced. In the above-mentioned embodiment, the substrate 11 and the corrugated plate 12 are joined by brazing, but welding is also possible. This welding is preferably spot welding or seam welding. Since the welding work is performed in the atmosphere, the work efficiency is extremely improved and the product can be manufactured at a low price.

[0014]

As is clear from the above description, the heat sinks according to claims 1 to 3 are manufactured at a very low cost because the heat sink is manufactured by joining the corrugated plate to the substrate. Is. Further, by selecting the thickness, pitch, and height of the long plate portion of the corrugated plate, it is possible to provide a heat sink that is lighter in weight and more efficient in cooling than the conventional extruded heat sink.

[Brief description of drawings]

FIG. 1 is a front view of a heat sink according to an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view showing the manufacturing process.

FIG. 4 is an explanatory diagram of a heat sink according to another embodiment.

FIG. 5 is a front view of a heat sink according to a conventional example.

[Explanation of symbols]

 10 Heat Sink 11 Substrate 12 Corrugated Plate 13 Pure Aluminum Plate 14 Silicon Aluminum Alloy 15 Long Plate Part 16 Pressing Teeth 17 Pressing Member 18 Valley Bottom 19 Small Hole

Claims (3)

[Claims] 1. A heat sink comprising a substrate and a fin having one end attached to the substrate, wherein the fin is a corrugated plate obtained by bending a thin aluminum plate at a right angle at a short pitch. A heat sink characterized in that a bent end plate portion on one side of the corrugated plate is joined by brazing or welding. 2. The long plate portion of the corrugated plate has 5 to 1
2. A large number of small holes are formed with an opening ratio of 5%.
Heatsink as described. 3. The corrugated plate has a thickness of 0.3 to 0.
About 8 mm, the folding pitch of the corrugated plate is 3 ~
5 mm, length of corrugated plate is 50-80 mm
The heat sink according to claim 1 or 2.