US 20040200608 A1
A fin for a heat sink is provided that includes a plate having a surface and an edge and at least one vane projecting outwardly from the surface and arranged relative to the edge so as to redirect a portion of a stream of air that is impinging upon the edge. A heat transfer system is also provided that includes a heat pipe having an elongate side and a fan that is arranged so as to direct a stream of air toward the elongate side of the heat pipe. At least one plate is arranged in parallel relation to a stream of air created by the fan. The plate includes an opening with the heat pipe positioned within the opening, a surface and an edge and at least one vane projecting outwardly from the surface and arranged relative to the edge so as to redirect a portion of the stream of air that is impinging upon the edge from the fan.
1. A fin for a heat sink comprising:
a plate having a surface and an edge and at least one vane projecting outwardly from said surface and arranged relative to said edge so as to redirect a portion of a stream of air impinging upon said edge.
2. A fin according to
3. A fin according to
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5. A fin according to
6. A fin according to
7. A heat transfer system comprising:
a heat pipe having an elongate side;
a fan arranged so as to direct a stream of air toward said elongate side of said heat pipe; and
at least one plate having an opening with said heat pipe positioned within said opening wherein said at least one plate comprises a surface and an edge and at least one vane projecting outwardly from said surface and arranged relative to said edge so as to redirect a portion of a stream of air impinging upon said edge.
8. A fin according to
9. A fin according to
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12. A fin according to
13. A heat transfer system comprising:
a cylindrical heat pipe having a central longitudinal axis;
a fan arranged to direct a stream of air at a substantially right angle to said central longitudinal axis of said heat pipe; and
a plurality of planar plates mounted upon said heat pipe in substantially perpendicular relation to said central longitudinal axis wherein each of said plates comprises at least one vane formed integrally with said plate and projecting outwardly from said surface and arranged relative to said fan so as to redirect that portion of a stream of air impinging upon said at least one vane.
14. A fin according to
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 The present invention generally relates to the management of thermal energy generated by electronic systems, and more particularly to a heat pipe-related device and method for efficiently and cost effectively routing and controlling the thermal energy generated by various components of an electronic system.
 A significant problem with electronic circuit board components, including integrated circuits, is that they generate substantial heat. Since the performance of most of these components is very sensitive to heat, it is necessary to provide some means of cooling the components. This problem has increased as technology has been developed allowing the components to be made smaller in size. This means that more components generating the same amount of heat are being packed into the same or even smaller enclosures. It also means that the surface area through which heat must be dissipated from each component has decreased.
 One type of heat-dissipating device that is often employed is a simple fan mounted within the enclosure and designed to circulate air through the enclosure. Such fans remove the hot air and introduce cooler air so as to dissipate the heat generated by the electronic components. Another method of removing heat is the use of a heat sink. The term “heat sink” is here used in its normal dictionary definition: “a substance or device for the absorption or dissipation of unwanted heat (as from a process or an electronic device).” Webster's Ninth New Collegiate Dictionary, p. 560 (1983). A typical heat sink used in the electronics industry for dissipating heat from components will comprise a base and a plurality of fins. The heat sink base is secured in firm heat-transfer engagement with an electronic component so as to absorb the heat from the component, passing it into the plurality of fins, which in turn radiate the heat into the surrounding air. Heat sinks are normally constructed from high heat-conducting material, such as metal, including aluminum and copper, or may comprise well known heat pipe technology. Heat sinks may be used in combination with one or more fans.
 A typical heat sink may be formed from an aluminum extrusion in which the base and fins are integral. The extrusion is then cut off in sections, each section forming an individual heat sink. Since the extrusion process results in fins that are in parallel planes, the fins form a plurality of passages between the fins extending in one direction. When a heat sink is formed with passages in one direction, it is desirable to have the fan and heat sink located relative to one another so that the air stream of the fan is parallel with the air passages between the fins. That is of course not always possible or desirable for other reasons.
 One of the shortcomings in the heat sinks described above is that they have a fixed orientation within the electronic system such that one or more fans must be arranged in a prescribed location in order to direct a stream of air over the surface of each fin. If a stream of air is needed to be directed in a different direction, a separate fan will be needed to do the job. In many electronic assemblies, the electronic components are mounted on a printed circuit board in close relation to one another. Therefore, mounting a heat sink on a particular electronic device is more or less circumscribed by the area (width and length) of the electronic component. This relationship also impacts the available real estate for positioning of fans. The thermal designer for the electronic assembly is therefore faced with specifying a custom-made heat sink of a particular height for a particular application, or attempting to accommodate the limited heat sink dissipation capability by selection and positioning of a more powerful fan. Thus, a heat sink with a fixed air flow requirement presents the thermal designer with a design restriction that is undesirable.
 In one embodiment, the present invention provides a fin for a heat sink comprising a plate having a surface and an edge and at least one vane projecting outwardly from the surface and arranged relative to the edge so as to redirect a portion of a stream of air that is impinging upon the edge. The plate may include a bent-edge that is bent outwardly relative to the surface so as to further redirect a portion of the stream of air that is impinging upon the first edge. In this way, the fin of the present invention may be used to cool a heat generating component that is directly attached to the fin, as well as, to direct a stream of air toward a heat generating component that is not directly attached to the fin, or that is in line with the general direction of the stream of air (or the fan creating the stream) so as to effect a thermal energy transfer from that adjacent component without the need for an additional fan.
 In another embodiment of the invention, a heat transfer system is provided that combines a heat pipe having an elongate side and a fan that is arranged so as to direct a stream of air toward the elongate side of the heat pipe. At least one plate is arranged in parallel relation to a stream of air created by the fan. The plate includes an opening with the heat pipe positioned within the opening, a surface and an edge and at least one vane projecting outwardly from the surface and arranged relative to the edge so as to redirect a portion of the stream of air that is impinging upon the edge from the fan.
 These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:
FIG. 1 is a perspective view of an electronic assembly comprising a plurality of plate fins having vanes for redirecting air flow formed in accordance with the present invention;
FIG. 2 is a perspective view of a plate fin formed in accordance with the present invention;
FIG. 3 is a partially broken-way, perspective view of a portion of the electronic assembly shown in FIG. 1 and a plurality of plate fins formed in accordance with the present invention;
FIG. 4 is a side elevational view one of the plate fins shown in FIG. 3, and indicating the direction of air flow from a fan;
FIG. 5 is a perspective view of an alternative embodiment of a plate fin formed in accordance with the present invention;
FIG. 6 is a perspective view of a further alternative embodiment of plate fins formed in accordance with the present invention; and
FIG. 7 is yet a further alternative embodiment of plate fins formed in accordance with the present invention.
 This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.
 Referring to FIGS. 1 and 2, the present invention comprises a fin assembly 5 that is adapted for mounting onto a portion of a heat transfer shaft 8, e.g., an elongate solid shaft of copper or aluminum or an elongate heat pipe, and assembled within an electronic system 9. Fin assembly 5 may comprise a stackable heat sink for an electronic component 10, where a plate 12 of heat-dissipating material, such as metal, provides the means for securing heat transfer shaft 8 to electronic component 10. Plate 12 has an opening for receiving a portion of heat transfer shaft 8. Heat transfer shaft 8 is generally cylindrical in shape, although it should be understood that the shaft cross-section could be square, rectangular, elliptical or other cross-sectional shapes as may be selected for the particular manufacturing process and the intended use of the heat sink.
 Fin assembly 5 comprises a plurality of individual fins 20 each comprising a substantially planar shape. It will be appreciated that the shape of each fin 20 may be rectangular, square, round, oval, or some other geometric shape. Each fin 20 is formed from a suitable heat-conducting material, such as a metal, e.g., aluminum, copper, or the like. Each fin 20 includes a central opening 22, although it will be understood that opening 22 need not be centered within the geometric shape, although that location may be preferable for maximizing the heat conduction from heat transfer shaft 8 to all portions of each fin 20. Opening 22 is often formed by stamping, with a dimension that is less than the dimension of heat transfer shaft 8. Opening 22 may be coined or swaged so as to create a force-fit with heat transfer shaft 8.
 Each fin 20 also includes at least one vane 30 which projects outwardly from a surface of the fin, and may or may not contact an adjacent fin 20. A plurality of vanes 30 are often formed in fin 20, in a staggered, substantially “V”-shaped pattern. Each vane 30 is canted or pitched so that a surface 32 is arranged at an angle relative to an edge 23 of fin 20. This canted arrangement of each vane 30 helps to direct a portion of a stream of air 33 (FIG. 3) away from heat transfer shaft 8 so as to exit fin 20 from edges 34 and 35. Vanes 30 may be formed by cutting and bending a correspondingly shaped portion of fin 20 outwardly, away from the remainder of fin 20. Vanes 30 are often arranged substantially perpendicularly with respect to the plane of fin 20, and also may comprise a curvature that is selected so as to catch and redirect air stream 33 impinging upon them from a fan 36 (FIG. 3).
 In an alternative embodiment of the present invention, edges 40 may be bent so as to form a baffle for further directing air stream 33, or the air stream that has been initially directed from vanes 30. One or more edges 34, 35, 40 may be bent for air flow control (FIGS. 4-7).
 In operation, fan 36 directs a stream of air 33 toward the edges of fins 20. (FIG. 3). As air stream 33 engages vanes 30, a portion of air stream 33 is directed outwardly, away from air stream 33 so as to be directed on other heat generating elements requiring convection cooling within electronic system 9. It will be understood that vanes 30 may be arranged in staggered patterns on the surface of fins 20 so that different portions of air stream 33 may be captured and redirected outwardly away from the fin assembly.
 It is to be understood that the present invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.