JP2003046037A - Corrugated matrix heat sink for cooling electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To markedly reduce the manufacture cost of a corrugated heat sink for cooling the electrical and electronic components, by easy assembly. SOLUTION: The heat sink comprises a primary corrugated fin pack 12, having a continuous series of primary vertically extended fins 15 defining channels between the adjacent pairs of the vertically extended fins. A secondary corrugated fin pack 11 fits within the channels of the primary corrugated fin pack, and a fin pack matrix 13 is assembled, and the fin pack matrix 13 is attached to a base plate 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This is July 10, 2000.
It is a regular application based on the preliminary application No. 60 / 217,088 filed on the date.

The present invention relates to cooling electrical and electronic components, and more particularly to corrugated heat sinks for cooling electrical and electronic components.

[0003]

BACKGROUND OF THE INVENTION Electrical and electronic components (eg, microprocessors, IGBTs, output semiconductors, etc.) generate heat that must be removed in order to obtain reliable operation and long life of the components. Since the dissipation of heat generated by the electronic components is continuously increasing, it is necessary to provide a more effective and efficient means of cooling these elements.

One method of removing heat from electronic components is to use a heat sink. Heat sinks consisting of a flat plate with a large number of elongated vertical fins have been the focus of attention for many years (20-30 years) as a primary means of dissipating heat from electronic components to the ambient air. Much time and effort has been devoted to improving heat sinks not only from a manufacturing point of view, but also from a design optimization point of view. What could happen is that the basic geometric parameters (fin thickness,
Theoretical optimization of fin height, number of fins or fin spacing) has resulted in difficulties versus manufacturing (and high cost) or unmanufacturable heat sink features. The problem stems from the fact that optimal heat sinks require fin densities and fin thicknesses that cannot be achieved when bound to standard manufacturing practices.

Recently, there have been five main approaches to heat sink manufacture: extrusion, casting, micro-forging, metal-to-metal working fins, corrugated fins. Each of these methods has a long and narrow air passage between the fins (ie,
(Similar to parallel plates) in the design of their fins.

The extrusion method involves extruding a billet of heated material through a hollow tool (called a die) to form a contour. The design of the tool is very demanding, as the large forces required to push the material out of the tool place great stresses on the tool, and if not designed properly, the tool will break. Tool-constrained designs make heat sink profiles very difficult to manufacture, and very difficult, especially when very thin, high, and dense fins are required. Recently,
Extrusion ratios of 6: 1 and 8: 1 (fin height to fin gap) are considered easy and can be obtained from many extruders. There are only a handful of extruders that can extrude even 11: 1 and even 15: 1, but only within a certain overall size range. Currently, the thermal requirements of electronic components in the electronic market are 25: 1 and 40:
This is done for heat sinks in the ratio range up to 1. These ratios are not currently available to extruders.

The casting method involves injecting molten metal into the die so that the metal conforms to the shape cut in the die. This method has three drawbacks. That is,
(1) the thermal properties of the material required for this method are lower than those of other methods, (2) the fin size and fin density are limited similarly to that of extrusion, but it is This is because. (3) The cost of this method only leads itself to very high volume applications.

[0008] Micro forging is by repeatedly pressing a heated billet into the die cavity (by high pressure).
It is a molding method. This method has fin size and fin density limitations as well as high volume requirements. The manufactured fin heat sink is made by making individual fins and by joining the fins to the base plate by a mounting method (metal to metal forming method such as swaging, epoxy bonding). While this method outperforms the fin height to gap ratio limitation of other methods, it still fails to provide the ratio achievable using corrugated fin technology.

Corrugated fin heat sinks are made by bonding the fin pack to the base plate by gluing, soldering, or brazing. A fin pack is a continuous piece of metal sheet folded into a corrugated shape. This method removes the fin thickness and fin density limitations of the other four methods and can be manufactured with theoretical optimization. However, one drawback is that maximum fin heights of only 10 cm (4 in) can currently be achieved. Nevertheless, heat sinks that require this fin height are not a common requirement on the market. Another drawback of this type of heat sink is that due to the long flow length, the high fin density impairs the air flow, resulting in a very high pressure drop which impairs the cooling capacity.

One common constraint for all heat sink designs manufactured by the method described above is that the design primarily utilizes the fins only vertically, ie perpendicular to the base plate. is there. A small number of extruded and / or manufactured fin heat sink designs have utilized spacing horizontally (perpendicular to the fins), but very slight fashion (small, thick secondary fins, fin irregularities, or Corrugated fin itself).

The designs described above do not make effective use of the cooling benefits obtained by utilizing surface area in the direction normal to the fins.

[0012]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a new heat sink. It will be appreciated that there is a continuing need for improved methods for removing heat from electrical or electronic components, especially heat sink designs that provide significant manufacturing and subsequent cost advantages over the prior art.

This need is addressed by the present invention, which proposes a novel solution for embedding small fin packs, ie corrugated fin units, between large fin packs. In accordance with one aspect of the present invention, an improved heat sink provides cooling from the surface of electrical and electronic components. The heat sink consists of at least one primary corrugated fin pack having a continuous series of vertically extending fins defining a channel between a pair of vertically extending fins. At least one secondary corrugated fin pack fits within the channel of the primary corrugated fin pack to create a fin pack matrix. The fin pack matrix is then attached to the base plate.

Accordingly, it is an object of the present invention to provide an improved heat sink design for cooling electrical and electronic components. Beyond heatsinks formed by alternating corrugated fins and separator sheets and brazing together, improved features in accordance with the present invention include reduced element count and simplified assembly that ultimately result in lower overall unit costs. Exists in

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, the most effective conventional heat sink design utilizes a maximum amount of surface area and includes multiple corrugated fins and separator sheets alternatingly stacked together and brazed together. Including. This method allows optimum use of the material by allowing the fin thickness to be optimized independently for vertical and horizontal channels. In essence, this feature has the potential to provide the heat sink with the best thermal performance due to the lowest pressure drop, lowest weight, and smallest size. However, one drawback of this design is the requirement to hold and braze many individual parts together which is labor intensive and costly. Although this feature is currently the most optimal feature, it is least used in the heat sink market, suggesting that it is too expensive to manufacture and reduces its market acceptance and success.

The present invention proposes a corrugated matrix heat sink for enhanced heat dissipation and improved production capacity. In FIG. 2, a preferred embodiment of a heat sink 10 made in accordance with the present invention is shown. The heat sink 10 comprises a plurality of small corrugated fin packs 11 embedded within the channels of thick, widely spaced corrugated fin packs 12. Primary corrugated fin pack 12
Consists of a number of vertically extending fins 15. A plurality of secondary corrugated fin packs 11 are inserted between adjacent pairs of fins 15. The secondary corrugated fin pack 11 has its fins 18
Are placed between the fins 15 so that they are in vertical relation to the fins 15 of the primary corrugated fin pack 12. A fin pack assembly consisting of fin packs 11 and 12 (herein referred to as fin pack body 13) is attached to a thick base plate 14. Fin pack 11
And 12 are typically made of aluminum, copper, or other heat-dissipating metal or metal alloy.

In FIG. 3, the fin pack 12 preferably comprises a continuous sheet folded into spaced vertical extensions 15 connected by horizontally extending tops 16a and bottoms 16b. Adjacent vertical extensions 15 define channels 17 that receive fin pack 11. Each fin pack 11 preferably consists of a continuous sheet folded into a horizontal extension 18 connected by connecting portions 19a and 19b.

Once the secondary corrugated fin pack 11 is housed within the channel of the primary corrugated fin pack 12, the secondary corrugated fin pack 11 is secured to the primary corrugated fin pack 12 by any suitable mounting method. It The fin pack matrix 13 widens the channels 17 and extends the fin pack 12 to allow unrestricted replacement of the fin pack 11, and also at the force required by the mounting method for the entire assembly. It is preferably assembled by compression. The fin pack 11 may be attached to the fin pack 12 by any suitable means such as conventional methods of brazing, soldering, or epoxy bonding. Simultaneously or subsequently, the corrugated fin pack body 13 is attached to the base plate 14 by any suitable method such as brazing, soldering, or gluing.

Referring to FIG. 4, a heat sink 10 'made in accordance with another embodiment of the present invention is shown.
The heat sink 10 'comprises a fin pack body 13 such as that of the preferred embodiment sandwiched between a first base plate 14 and a second base plate 14'. Only one as sometimes required by the heat sink market
Although having one base plate 14 is most common, base plates on either side of fin pack body 13 (ie, 14 and 14 ') are desired for mounting electronic components. It is obvious to a person skilled in the art that other embodiments may fall within the scope of the present invention.

As shown, manufacturing a heat sink by embedding small corrugated fin packs within the channels of large corrugated fin packs offers significant manufacturing and resulting cost advantages. The thermal advantage lies in the optimal choice of fin thickness and fin density for the two fin packs of heat dissipation matrix. Those skilled in the art will understand that the optimum value depends on all of the unique constraints for each given application. These constraints can include selected fans, weight and / or size constraints, required heat dissipation, maximum element coupling temperature, maximum ambient cooling air temperature, operating environment cleaning. Manufacturing and cost advantages reside in ease of assembly and consequent increased productivity.

[Brief description of drawings]

1 is a front view of a conventional stacked corrugated fin heat sink. FIG.

2 is a perspective view of a preferred embodiment of a heat sink constructed in accordance with the present invention. FIG.

FIG. 3 is a front view of a preferred embodiment of a heat sink constructed in accordance with the present invention.

FIG. 4 is a front view of a modified embodiment of the heat sink according to the present invention.

[Explanation of symbols]

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E322 AA01 AB02 AB06 FA04                 5F036 AA01 BB05 BC05 BC06

Claims (10)

[Claims] 1. A continuous series of primary vertically extending fins having at least one primary corrugated fin pack defining a channel between successive pairs of fins, and a continuous series of secondary vertically extending fins. At least one secondary corrugated fin pack, wherein the secondary corrugated fin pack fits within a channel of the at least one primary corrugated fin pack, and an adjacent pair of the at least one primary corrugated fin pack. A fin pack matrix made by inserting said at least one secondary corrugated fin pack between vertically extending fins; at least one base plate; and said fin pack matrix on said at least one base plate An improved heat sink consisting of mounting means. 2. The improved heat sink of claim 1, wherein the at least one primary corrugated fin pack comprises one primary corrugated fin pack. 3. The at least one secondary corrugated fin pack comprises a plurality of secondary corrugated fin packs for insertion into the channels of the at least one primary corrugated fin pack. Improved heatsink. 4. The plurality of secondary corrugations such that the primary vertical extension fins of the at least one primary corrugated fin pack are in vertical relationship with the secondary vertical extension fins of the plurality of secondary corrugated fin packs. The improved heat sink of claim 3, wherein fin packs are disposed within channels of the at least one primary corrugated fin pack. 5. The improved heat sink of claim 1, wherein the at least one primary corrugated fin pack and the at least one secondary corrugated fin pack comprise a heat dissipating metal or metal alloy. 6. A method of cooling one or more heat generating electrical or electronic elements, the method comprising: at least one primary corrugated fin pack having vertically extending fins defining channels between adjacent pairs of vertically extending fins. Providing at least one secondary corrugated fin pack having vertical extension fins, wherein the vertical extension fins of the at least one primary corrugated fin pack are vertical extension fins of the at least one secondary corrugated fin pack. Thicker and wider spaced, said at least one so as to create a fin pack matrix
Inserting two secondary corrugated fin packs into the at least one primary corrugated fin pack; attaching the fin pack matrix to at least one base plate. 7. The method of claim 6, wherein the at least one primary corrugated fin pack comprises one primary corrugated fin pack. 8. The method of claim 6, wherein the at least one secondary corrugated fin pack comprises a plurality of secondary corrugated fin packs for insertion into channels of the at least one primary corrugated fin pack. Method. 9. The at least one primary vertically extending fin of the at least one primary corrugated fin pack is in vertical relationship with the secondary vertically extending fin of the at least one secondary corrugated fin pack. 7. The method of claim 6, further comprising placing the at least one primary corrugated fin pack within a channel of the primary corrugated fin pack. 10. The at least one primary corrugated fin
7. The method of claim 6, wherein the pack and at least one secondary corrugated fin pack comprises a heat dissipating metal or metal alloy.