Pulsating heat pipe heat sink

Abstract

A heat pipe heat sink. The heat pipe heat sink has at least one meandering channel for guiding a cooling medium, with at least two components which delimit the cross-section of the at least one channel. At least the first component is manufactured using a primary shaping process and may have fins arranged parallel to one another for laterally delimiting the cross-section of the at least one channel.

Description

FIELD

[0001] The present invention relates to a pulsating heat pipe heat sink, hereinafter referred to simply as heat pipe heat sink, which is characterized by a particularly advantageous manufacture, whereby, among other things, the desired thermomechanical properties can be adapted to the particular application in a particularly simple and advantageous manner.BACKGROUND INFORMATION

[0002] Certain heat pipe heat sinks are described in the related art. Such a heat pipe heat sink is characterized by at least one, typically meandering, channel, which serves to guide a vaporizable cooling medium, such as glycerin or the like. The mode of operation of such a heat pipe heat sink is such that, at an evaporator region of the heat pipe heat sink arranged at least in indirect contact with a heat-generating component, the cooling medium located in the at least one channel is heated to a temperature above its boiling point and evaporates, whereby it reaches a condenser region of the heat pipe heat sink by pressure pulsation, in which condenser region the evaporated cooling medium condenses again and can thus flow back into the evaporator region.

[0003] Typically, such a heat pipe heat sink comprises a central body or a first component, in which the at least one channel is formed, which is closed off on its two opposite sides with end caps or similar components. The end caps or similar components serve to reverse the flow of the cooling medium between two adjacently arranged portions of the at least one channel, which forms the separated portions by means of fins in the first component. This makes the meandering guidance or flow of the cooling medium within the heat pipe heat sink possible. It is conventional to form the central body, for example, as an extruded profile or from multiple components connected to one another.SUMMARY

[0004] A (pulsating) heat pipe heat sink according to the present invention has the advantage that it can be optimally adapted to the particular application. In particular, a wide variety of geometries of the fins, which laterally delimit the portions of the channel, can be realized particularly easily in terms of manufacturing technology. In addition, it is possible to realize not only flat heat sinks, i.e., heat sinks whose central or first component has a constant cross-section, but also heat sinks that have a special geometry, for example fins that widen in width, or the like, in the region in which the heat pipe heat sink is arranged in heat-conducting contact with components to be cooled.

[0005] In contrast to the related art, the present invention is based on the idea of using two components to form the region of the heat pipe heat sink that forms the at least one channel: a first component, which is manufactured using a primary shaping process, and a second component, which covers the first component at least in the region of the fins. The primary shaping process makes it particularly easy to realize a wide variety of geometries or arrangements of the fins in the first component. In contrast, the second component in the form of a cover or base serves to delimit the cross-section of the at least one channel or to make the heat pipe heat sink media-tight. For this purpose, the first and the second component are typically connected by means of a material bond such that leakage of the pressurized cooling medium in the region of the at least one channel is avoided.

[0006] According to an example embodiment of the present invention, a heat pipe heat sink has at least one meandering channel for guiding a cooling medium. Furthermore, the heat pipe heat sink comprises at least two components, which delimit the cross-section of the at least one channel. The first component is manufactured using a primary shaping process and preferably has fins arranged parallel to one another for laterally delimiting the cross-section of the at least one channel. Lastly, it is provided that the second component covers the first component at least in the region of the at least one channel in the manner of a cover or base.

[0007] In particular but not restrictively, a primary shaping process for the first component is understood to mean a die-casting process, an impact extrusion process, a forging process, or an extrusion process. Materials that can be used to form the first and / or second component include copper, aluminum, iron, steel, titanium, and their alloys. As already explained above, the connection between the two components is preferably made by a material bond. In particular and also not restrictively, this involves a laser welding process, an adhesive bonding process, friction stir welding, or the like.

[0008] Advantageous developments of the heat pipe heat sink according to the present invention are disclosed herein.

[0009] A first preferred structural design of the present invention provides that the fins have different widths at least over a subportion of their longitudinal extent. The different widths of the fins lead to different widths of portions or different cross-sections of the at least one channel (if the heights of the fins are the same), which has proven to be advantageous depending on the application in order to change a local flow velocity of the cooling medium.

[0010] A further preferred embodiment of the heat pipe heat sink of the present invention provides that the fins are rectangular and / or trapezoidal in cross-section. Both rectangular fins and trapezoidal fins can be used within a heat pipe heat sink. The cross-sections of the fins can, for example, be rounded in the region in which the fins are connected to the second component. It is also conceivable that the connections between the two components in the region of the fins are not consistently tight. Rather, it may also be possible for small gaps between the fins and the second component to be permitted, which may arise, for example, due to the dimensional tolerances during the manufacture of the components. The only important thing is that the two components are media-tight to the outside, i.e., that no cooling medium leaks from the heat pipe heat sink.

[0011] A further advantage of the heat pipe heat sink of the present invention is that the geometry of the heat pipe heat sink can be easily adapted locally to the existing conditions or the arrangement of components to be cooled. For this purpose, it is in particular provided that, at least in some areas, the first and / or second component has regions which are raised in a direction running in the height direction of the fins. These raised regions can then, for example, be arranged in direct heat-conducting contact with components to be cooled, without the need for intermediate elements or the like.

[0012] The fins can also have different heights. This has the result that the cross-section of the channel also varies in size locally (assuming the same distance between the individual fins). This allows a local adjustment of the flow velocity or of the heat transfer properties.

[0013] According to the present invention, a further preferred structural design of the heat pipe heat sink for local adaptation to components to be cooled or for influencing the effect of the cooling medium provides that the first and / or second component has at least one raised portion of increased wall thickness on the outer side facing away from the at least one channel.

[0014] In particular, in the event that the second component not only is designed in the form of a (flat) cover or base but also has flow elements or fins, it can be provided that the second component is manufactured using the primary shaping process and that some of the fins are formed on the second component. This allows advantageous properties to be achieved in that, for example, particularly narrow distances between the fins can be realized, which cannot be achieved or can only be achieved with difficulty by forming all fins on the first component alone.

[0015] In order to allow a type of form-fitting connection between the two components in the region of the fins or to be able to design material bonds particularly simply and effectively, it can be provided that the fins engage in recesses of the first and / or second component.

[0016] The heat pipe heat sink typically requires flow deflection elements in the region between two directly adjacent fins, which flow deflection elements allow the cooling medium to flow in different directions in the two directly adjacent channels for forming the meandering channel. For this purpose, a third component is provided for deflecting the flow between the fins. Of course, it is also possible to form corresponding elements or the corresponding flow deflections on the first and / or second component.

[0017] As explained above, it is important that the heat pipe heat sink is media-tight to the outside. For this purpose, according to an example embodiment of the present invention, it is provided that at least the first component and the second component are connected to one another in a media-tight manner by a material bond at least in edge portions.

[0018] Further advantages, features, and details of the present invention can be found in the following description of preferred embodiments of the present invention and with reference to the figures.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a longitudinal section through a first heat pipe heat sink in the region of its first component manufactured using the primary shaping process, according to an example embodiment of the present invention.

[0020] FIG. 2 to FIG. 4 show partial cross-sections through a heat pipe heat sink to illustrate differently designed fins on the first component and differently shaped second components, according to example embodiments of the present invention.

[0021] FIG. 5 shows a longitudinal section, as shown in FIG. 1, of a heat pipe heat sink which has fins that are enlarged in width in some areas, according to an example embodiment of the present invention.

[0022] FIG. 6 and FIG. 7 show partial cross-sections through modified heat pipe heat sinks which have local recesses or raised portions, according to example embodiments of the present invention.

[0023] FIG. 8 to FIG. 11 show partial cross-sections through further modified heat pipe heat sinks which have recesses for the arrangement of the cooling fins, according to example embodiments of the present invention.

[0024] FIG. 12 shows a partial cross-section, as shown in FIG. 8 to 11, in which recesses for fins are formed on both components.

[0025] FIG. 13 shows a partial cross-section through a heat pipe heat sink in which the second component is deformed in a wave-shaped manner, according to an example embodiment of the present invention.

[0026] FIG. 14 to FIG. 16 show longitudinal sections through heat pipe heat sinks with specially designed deflection regions using two components, according to example embodiments of the present invention.

[0027] FIG. 17 shows a longitudinal section through a heat pipe heat sink in which the deflection regions are realized by a third component, according to example embodiments of the present invention.

[0028] FIG. 18 shows a longitudinal section through a heat pipe heat sink in which the second component engages in an edge-side peripheral recess of the first component, according to example embodiments of the present invention.

[0029] FIG. 19 shows a partial cross-section in plane A-A of FIG. 18.

[0030] FIG. 20 is a perspective view of a second component, in which the second component has raised regions for contacting heat-generating components, according to example embodiments of the present invention.DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0031] Identical elements or elements which have the same function are provided with the same reference signs in the figures.

[0032] The (pulsating) heat pipe heat sink 10 shown in longitudinal section in FIG. 1 serves to cool, in particular, electronic components or parts (not shown) which give off heat during operation. For this purpose, in a conventional manner and therefore not shown, the heat pipe heat sink 10 is connected on an evaporator side 13 of the heat pipe heat sink 10 in a heat-conducting manner to the component(s) to be cooled or to an assembly to be cooled. The heat-conducting connection can be made, for example, via a thermal adhesive or by direct mechanical connection to the heat pipe heat sink 10.

[0033] Within the heat pipe heat sink 10, a cooling medium (not shown) in the form of a vaporizable liquid is arranged in at least one channel 11. The cooling medium, which is evaporated by the heat of the component or assembly to be cooled, flows within the at least one channel 11 of the heat pipe heat sink 10 from the evaporator side 13 to a condenser side 14, where the cooling medium is cooled again by the ambient cold or in some other way to a temperature below the condensation temperature, whereupon it flows back in the direction of the evaporator side. The mode of operation of such a heat pipe heat sink 10 is conventional and is therefore not explained further.

[0034] The heat pipe heat sink 10 has a housing 12, which comprises at least two components 16, 18, wherein the component 18 can only be seen in FIG. 2 to FIG. 4. The two components 16, 18 are connected to one another in a media-tight manner at least in some areas such that the cooling medium located in the channel 11 of the heat pipe heat sink 10 cannot leak from the housing 12 of the heat pipe heat sink 10.

[0035] Whereas the first component 16 is manufactured by a primary shaping process and in particular consists of aluminum or an aluminum alloy, the second component 18 can be manufactured both using the primary shaping process and in some other way, for example by a deformation process from a (flat) sheet metal part or the like. Preferably, the second component 18 consists of the same material as the first component 16 in order to avoid thermal stresses due to different expansion coefficients.

[0036] The first component 16 is trough-shaped and has a flat base portion 22 in a plane running parallel to the plane of the drawing in FIG. 1. The base portion 22 is delimited by a peripheral edge portion 24 as shown in FIG. 1. Within the edge portion 24, the first component 16 has multiple fins 26 arranged parallel to one another for guiding the cooling medium within the meandering channel 11. The channel 11 also has deflection regions 28, 30 at the front end regions of the fins 26 for the cooling medium so that the cooling medium guided between the fins 26 can flow alternately in one direction or the other in the direction of the channel 11 according to the arrows 31, 32.

[0037] The edge portion 24, together with the fins 26, forms a (single) endless channel 11 for the cooling medium in the exemplary embodiment shown in FIG. 1. For this reason, the channel 11 has a connecting channel 35 on the side of the deflection regions 30 which faces away from the deflection regions 28, which connecting channel connects the two edge-side channel portions 37, 38 of the channel 11 to one another.

[0038] In addition, it is mentioned that, in a modification of the exemplary embodiment shown in FIG. 1, without the connecting channel 35, the channel 11 can also be designed as a channel 11 closed on both sides, as is also conventional.

[0039] As can be seen in FIG. 1, the fins 26 can have different widths by, b2, wherein the width b2 is greater than the width b1. In the exemplary embodiment shown, the fins 26 of different widths alternate in a direction running in the direction of the arrow 33.

[0040] The cross-section of the fins 26 can also be designed in different ways. In this respect, reference is first made to FIG. 2. It can be seen in FIG. 2 that fins 26a are provided, which have a rectangular cross-section. In view of the above explanation, the width of the fins 26a can differ. In addition, fins 26b which have oblique flanks are also shown in the exemplary embodiment shown in FIG. 2. In particular, the cross-section of the fins 26b may also be trapezoidal.

[0041] FIG. 2 also shows that the second component 18 serving as the cover element 19 is connected to the first component 16 at least in the region of the edge portion 24, and additionally also in the region of most of the fins 26a, 26b. The connection between the two components 16, 18 can in particular be designed in the form of a material bond 36. In particular but not restrictively, a material bond is understood to mean brazing, soldering, welding (in particular laser beam welding), or possibly gluing. It can also be seen in FIG. 2 that small gaps 38 may be formed between the fins 26a, 26b and the second component 18 in the regions in which no material bond 36 is formed. However, depending on the manufacturing process or component tolerances as well as the material bond 36, there may also be contact between the fins 26a, 26b and the second component 18, even if no material bond 36 is formed there.

[0042] FIG. 3 shows the case in which the fins 26b are formed with rounded portions 40 on the side facing the second component 18.

[0043] In contrast, the heat pipe heat sink 10a according to FIG. 4 has only fins 26a having a rectangular cross-section. In contrast to the second component 18 according to FIG. 1 to 3, the second component 18a is only flat within the edge portion 24 of the first component 16a. Outside the edge portion 24, the second component 18a has an obliquely arranged edge 46 projecting toward the first component 16a and having portions 48 running parallel to the base portion 22 of the first component 44. In the region of the portions 48, the second component 18a can additionally be connected to the first component 16a, in particular by a material bond (not shown). This is in particular provided when only one contact is formed between the edge portion 24 of the first component 16a and the second component 18a.

[0044] FIG. 5 shows a heat pipe heat sink 10b, the first component 16b of which comprises, in addition to fins 26 possibly having a different width b1, b2, fins 52 which, when viewed in the longitudinal direction of the fins 52, in some areas have a width b3 that is enlarged relative to the width b1, b2 such that portions 53 which are raised over a partial region of the longitudinal extent of the fins 52 are formed on opposite sides of the fins 52. This reduces the flow cross-section of the channel 11 in the region of the portions 53.

[0045] FIGS. 6 and 7 show heat pipe heat sinks 10c and 10d, in which the first component 16c, 16d has a region 55, 56 which is raised relative to the rest of the surface. Whereas the second component 18c of the heat pipe heat sink 10c is designed as a flat component, the second component 18d of the heat pipe heat sink 10d is adapted to the shape of the first component 16d so that the height h of the channel 11 within the heat pipe heat sink 10d is constant due to the raised region 57. In contrast, the channel 11 of the heat pipe heat sink 10c has different heights h1, h2.

[0046] FIG. 8 to 11 show further heat pipe heat sinks 10e to 10h sectionally. The heat pipe heat sinks 10e to 10h are all characterized in that the second components 18e to 18h each have groove-shaped recesses 63, 64, into which the end faces of the fins 65, 66 of the first components 16e to 16h dip. Whereas the recesses 63 each have a rectangular cross-section corresponding to the rectangular cross-section of the fins 65, the recesses 64 are each rounded, wherein the fins 66 on the side facing the recesses 64 can be either flat or rounded.

[0047] In FIG. 12, the heat pipe heat sink 10i has a first component 16i with an edge portion 24, which, when viewed in the direction of the double arrow 66, alternately has recesses 67, rounded recesses 67 in the exemplary embodiment, and fins 26, rounded fins 26 in the exemplary embodiment. The second component 18i, like the first component 16i, is manufactured using the primary shaping process and, in the exemplary embodiment, has rectangular recesses 68 for receiving the end faces of the fins 26 of the first component 16i, and fins 26 which are rectangular in cross-section and project into the recesses 67 of the first component 16i.

[0048] FIG. 13 shows a heat pipe heat sink 10j in which the second component 18j is designed in the form of a corrugated sheet metal part. The second component 18j is connected in the region of recesses 69 to some of the fins 26 of the first component 16j, in particular by laser weld seams 70.

[0049] In the heat pipe heat sink 10k shown in FIG. 14 and comprising the two components 16k, 18k, fins 26 are formed in the first component 16k, whereas the second component 18k, which is also manufactured using the primary shaping process, has fins 26k. When viewed in the direction of the double arrow 71, the fins 26, 26k of the two components 16k, 18k alternate. On one side of the heat pipe heat sink 10k, the first component 16k also has a deflection portion 72 which runs in the direction of the double arrow 83 and in which the end faces of the fins 26, 26k are arranged alternately.

[0050] The heat pipe heat sink 101 shown in FIG. 15 differs from the heat pipe heat sink 10k in that the deflection portion 721 is part of the fins 261 formed on the second component 181.

[0051] In the heat pipe heat sink 10m shown in FIG. 16, its deflection portion 72m is formed on the second component 18m, whereas all fins 26 are formed on the first component 16m.

[0052] FIG. 17 shows a heat pipe heat sink 10n, which is formed from a third component 74 in addition to the two components 16n and 18n with the fins 26. The third component 74 forms the deflection portion 72n.

[0053] FIGS. 18 and 19 show a heat pipe heat sink 100, the second component 18o of which is completely inserted within a recess 76 of the first component 16o. The first component 18o also comprises local or linear raised portions 78, which penetrate corresponding opposing openings on the second component 18o. In the region of the raised portions 78, the connection between the two components 16o, 18o is made, for example, by friction stir welding.

[0054] Lastly, FIG. 20 shows a heat pipe heat sink 10p, which is characterized in that either the first component 16p and / or the second component 18p is formed with one or more raised portions 80 on the outer side facing away from the channel 11 (not shown), in order to shorten a distance between the heat-conducting components. In the region of the raised portions 80, the heat pipe heat sink 10p has an increased wall thickness on the first and / or second component 16p, 16p, which increased wall thickness can be realized particularly easily in terms of manufacturing technology by the primary shaping process.

[0055] The heat pipe heat sink 10, 10a to 10p described thus far can be altered or modified in many ways without deviating from the scope of the present invention.

Claims

1-10. (canceled)11. A heat pipe heat sink, comprising:at least one meandering channel configured to guide a cooling medium;at least two components which delimit a cross-section of the at least one channel, wherein a first component of the at least two components is manufactured using a primary shaping process and has fins arranged parallel to one another for laterally delimiting the cross-section of the at least one channel, and wherein a second component of the at least two components covers the first component at least in a region of the at least one channel as a cover or base.

12. The heat pipe heat sink according to claim 11, wherein the fins have different widths at least over a subportion of their longitudinal extent.

13. The heat pipe heat sink according to claim 11, wherein the fins are rectangular in cross-section and / or trapezoidal in cross-section.

14. The heat pipe heat sink according to claim 11, wherein, at least in some areas, the first component and / or the second component has regions raised in a direction running in a height direction of the fins.

15. The heat pipe heat sink according to claim 14, wherein the fins have different heights.

16. The heat pipe heat sink according to claim 11, wherein the first component and / or the second component has at least one raised portion of increased wall thickness on an outer side facing away from the at least one channel.

17. The heat pipe heat sink according to claim 11, wherein the second component is manufactured using the primary shaping process, and some of the fins are formed on the second component.

18. The heat pipe heat sink according to claim 11, wherein the fins engage in recesses of the first component and / or the second component.

19. The heat pipe heat sink according to claim 11, further comprising a third component configured to deflect a flow of the cooling medium between the fins.

20. The heat pipe heat sink according to claim 11, wherein at least the first component and the second component are connected to one another in a media-tight manner by a material bond at least in edge portions.

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