GB2339897A

GB2339897A - A Heat sink

Info

Publication number: GB2339897A
Application number: GB9815579A
Authority: GB
Inventors: Ben Kibel
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-07-20
Filing date: 1998-07-20
Publication date: 2000-02-09
Also published as: GB9815579D0

Description

2339897 HIGH PERFORMANCE HEAT SINK Heat sinks for cooling electronic

components and the like have been in use for many years now. They usually comprise of a metal plate with fins protruding from it. Air flows over the fins by convection or is forced to flow by a fan. Heat flows from the component to the heat sink and then from the heat sink to the air. In order to achieve a high performance from a small heat sink it must have a high fin density and the shortest possible path from the component to the fin.

High fin density heat sinks cannot be made by the extrusion process they are usually fabricated from plates of metal. The fins are bonded on to a plate or into slots cut in a plate. The production process is costly and there is a limit to the fin density that can be practically achieved.

According to the present invention the heat sink is constructed from many plates of two or more different shapes that are laminated together. The surface where the component is mounted is narrow allowing air to flow either side of the component. The air flow remains mostly perpendicular to the component mounting surface thus minimising the distance from component to fin and allowing the air to flow with little change in direction. The space behind the component mounting surface is filled with a core that is shaped to reduce both turbulence and thermal resistance between component and fin.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which; Figure 1 shows in perspective an exploded view of the heat sink. I have shown four fins 1 and three core plates 2 for clarity. A typical heat sink would actually have eighty fins 1 and seventy nine core plates 2.

Figure 2 shows in perspective an assembled heat sink with only ten fins 1 shown for clarity.

Figure 3 shows the fan duct 4 that is used in conjunction with a fan.

Figure 4 Shows the duct 4 in place on the back of the heat sink.

Figure 5 shows in cross section the heat sink with a fan 5, the duct 4 and a component being cooled 6 fifted. The air flow through the heat sink has been shown by stream lines 7.

Referring to the drawing the heat sink comprises of fin I and core plate 2 stacked alternately. Component mounting plate 3 is attached to the face created by the edge of fins 1 and core plates 2 in the stack. In this example methods of fixing the plates together have not been shown as the plates could be fixed together in many different ways e.g. Soldered, riveted, glued, welded etc. Figure 3 shows an example of a fan duct. The duct 4 is fitted over the back of the heat sink and pardy encloses the fins 1 this is shown in figure 4. The duct 4 forces the air to flow through the fins 1 and close to the core 2.

The benefit of allowing the air to flow either side of the component mounting plate 3 can be seen in figure 5 the air is allowed to flow close to the component mounting plate 3 and core 2 yet is not greatly impeded. The core plates 2 fill space that wouild have poor air flow they greatly reduce thermal resistance between the component mounting surface and fins and reduce turbulence by creating a smooth path for the air to flow over.

The purpose of the component mounting plate 3 is to provide a solid flat surface on which to mount the component being cooled 6. This plate is not essential particularly if the fins 1 and core plates 2 were soldered together as this would create a virtually solid " surface that could be machined flat and the component being cooled 6 could be mounted directly to this surface.

Claims

1 A heat sink comprising of a number of plates of two or more different shapes stacked alternately to produce a finned assembly.

2 A heat sink as claimed in claim 1 wherein the air is allowed to flow either side of the component mounting face.

3 A heat sink as claimed in claim 1 or 2 Wherein the space behind the component is filled with a core that is shaped to reduce turbulence and reduce thermal resistance between component and fin.

3 A heat sink as in claims 1 or 2 or 3 wherein the air flow is predominantly perpendicular to the component mounting surface.

4 A heat sink substantially as described herein with reference to Figures 1-4 of accompanying drawing.

Amendments to the claims have been filed as follows CLAIMS A heat sink comprising a heat-conducting body having a component mounting face for thermal contact with a component to be cooled, and a plurality of substantially parallel cooling fins projecting from an opposite side of said body with respect to the component mounting face to form a plurality of air flow passages between the cooling fins, and in which the fins extend beyond two opposite flanks of the component mounting face.

2. A heat sink according to Claim 1, in which said heat conducting body comprises a pair of mutually inclined faces disposed in said air flow passages and which diverge towards the component mounting face.

3. A heat sink according to Claim 1 or 2 in combination with means for creating an air flow through said passages.

4. A heat sink according to Claim 3, in which said means for creating an air flow is mounted on the opposite side of the heat sink with respect to the component mounting face.

5. A heat sink according to Claim 3 or 4, in which said means for creating an air flow comprises a fan.

6. A heat sink according to Claim 3, 4 or 5, provided with an air duct which partially surrounds said cooling fins.

I Is 11 P899

7. A heat sink substantially as described herein with reference to Figures 1 to 4 of accompanying drawings.