WO2014206578A2

WO2014206578A2 - Housing, cooling body and method for producing a cooling body for cooling electric and/or electronic components

Info

Publication number: WO2014206578A2
Application number: PCT/EP2014/001785
Authority: WO
Inventors: David BURKHARDT
Original assignee: Protonet GmbH
Priority date: 2013-06-28
Filing date: 2014-06-30
Publication date: 2014-12-31
Also published as: WO2014206578A3; DE102013010867B4; DE102013010867A1

Abstract

The invention relates to a housing, a cooling body and a method for producing a cooling body for cooling electric and/or electronic components. The convection-cooled housing comprises a plurality of openings on the upper side of the housing, and a cooling body which comprises at least one lamella, arranged in such a manner, on the upper side of the housing, with respect to the plurality of openings such that an air flow passing through the housing is directed directly to the lamella which is arranged above.

Description

Housing, heat sink and method for producing a heat sink for cooling electrical and / or electronic components

The present invention generally relates to cooling of electronic and / or electrical components. More specifically, the present invention relates to a convection-cooled housing, a heat sink, and a method of manufacturing a heat sink for cooling electrical and / or electronic components.

Housing for modular electronic or electrical components (also referred to as components and / or components) in particular power semiconductors and / or SMD (surface-mounted device) components must have a specified operating temperature (eg Intel 7 Series Chipset / C2160: 108 ° C maximum inside of the chip and 104 ° C on the package surface of the chip) for the components included in the package. Such housings include, for example, PC housings, server housings, control and / or control cabinets. Electronic or electrical components include, for example, electrical conductors such as cables, printed circuit boards, superconductors, waveguides such as antenna elements, circulators, electromechanical components e.g. for power supply, for frequency generation, passive components such as e.g. Resistors, capacitors, active devices, e.g. Tube discrete semiconductors and power semiconductors, integrated circuits, actuators, and / or sensors.

At a critical working temperature, the life of the components may be limited and / or a stable function can not always be guaranteed. A critical working temperature of a component may be a manufacturer's limit value. Depending on the robustness of the process and the intended durability of the component, the manufacturer chooses a suitable temperature range. The physical degradation processes that underlie this, on the other hand, scale exponentially with increasing temperature and current density. Manufacturers therefore choose a permissible operating range for a specific service life. For example, in Texas Instruments most chips are approved for the commercial sector eg for permanent temperatures 0-70 ° C. A maximum temperature is usually slightly higher (95-110 ° C), depending on the chip application, z. For example, in graphics processors where an error (so-called softerror) would only mean a short frame disturbance, higher limits (110 ° C) apply than with application processors (95 ° C). Consequently, in cases with high electrical power density (eg 50W / cm ^{2 of} a 130 watt CPU with 263mm ² die area (Core i7 Bloomfield)) active cooling (also referred to as forced cooling) is used. In this case, small heat sink and / or one or more fans, which promote air for heat exchange, are often used. Such fans allow a reduction in the size of the heat sink with constant temperature resistance. Thus, the delivery rate is increased accordingly to come to a similar thermal resistance, which is achieved by a larger heat sink without forced ventilation. The disadvantage is that such fans increase emissions such as energy consumption, dust, and / or sound. In addition, fans, such as any additional component, increase the potential for failure of the device to be cooled (eg bearing damage).

In the industrial environment, convection-cooled housings are also used. Convection-cooled housings include, for example, external aluminum heat sinks (also referred to as extrusion), internal heat-conducting bridges (eg, heatpipes, copper and / or aluminum blocks), and / or a largely closed housing. Housings that include only mounting joints and / or openings for power supply and / or peripheral connections that are not air or dustproof can be said to be largely closed. This heat can be dissipated to the housing surface. In addition, it can be avoided that dust penetrates into the housing interior. The disadvantage is that the construction by means of aluminum extrusions is very material-intensive, expensive and / or energy-consuming to manufacture. The design options are also limited in extrusion parts. Moreover, in such a convection cooling a cooling of components and in particular of SMD components inside the housing which are not connected to the heat sink with heat sinks, can not be guaranteed. This is particularly problematic for the development of increasingly powerful semiconductor platforms with ever greater component density. Unlike SMD devices, the cooling of upright THT (through-hole technology) devices can be easily guaranteed by slip-on heatsinks, soldered THT heatsinks and / or by ceramic chip packages and / or those with integrated metal plate. By contrast, the much smaller SMD components are produced almost exclusively in the plastic package, which can not emit the waste heat through its own surface because the temperature resistance of the plastic package is too high and / or the surface is no longer sufficient due to the increasing miniaturization. Instead, the cooling must be released through the heat-conducting leads and / or BGA pads connected to the chip DIE to the board, which then serves as a cooling lug. Thus, the board with the associated thermally conductive copper conductor tracks serves as a heat sink for SMD components in such an arrangement. For this purpose, some boards additional surfaces and / or additional cooling layer (German: layers) are installed to avoid glued and / or soldered heat sinks. Consequently, with such a cooling, the integration density of components is limited not only by the size and / or number of layers and / or vias and by the format of the SMD components, but also by the thermal resistance of the board. In particular, most commercially available circuit boards are designed for airflow and have no sufficient cooling surface to be able to install them in a closed passive housing. As a result, fans are used to cool powerful device. Through the use of fans, both the heatsink of the connected component (IC such as CPU, graphics chip, power electronics such as mosfet, linear regulator, etc.) is cooled and the air flow caused is reduced. In addition, the heat exchange between the board and the ambient air can be reduced because there is more volume flow and / or a reduced laminar or laminated sliding layer.

In addition, there are approaches to cooling components that are buried in transformer oil and / or where there are small thermal bridges for each component (usually with Wärmeleitpads, GapPads). But such cooling is relatively inflexible, expensive and / require low tolerances in the Series production are not given. Consequently, such cooling is not suitable for industrial use and / or mass production.

As already described, in casings with high electrical power density, active cooling is used, wherein heat sinks and fans are inserted into the housing. Heat sinks, also referred to as heat sinks, are, for example, milled heatsinks, scraped heat sinks (also referred to as skiving fins), extruded heatsinks, drop forged heatsinks, cast heatsinks, heatsinks made from laminations. Heatsinks may include measures to reduce the temperature resistance, for example by improved heat distribution, heat pipes, water circuits, compressors, copper inserts, which can be switched before or between the heat sink in the housing.

If a heat sink made of laminations, soldered, pressed and / or plugged, so relatively little material is installed, because thin slats are used and / or material mix (for example, a copper base plate, aluminum fins) requires only minimal additional effort.

Although both milled heat sink and scraped heat sink may reach a similar lamella density and similar thin material cross-sections as the laminations, but are much more complex in the production and in materials and format severely limited.

Extrusion heatsinks, cast and drop forged heat sinks have much larger lamellae or pins due to production than are possible with laminations. Consequently, they are heavier and less scalable than a heat sink made of laminations.

Accordingly, finned heat sinks have prevailed in the high performance area. For example, aluminum heat sinks with inserted lamellas and / or lamellae soldered between flat tubes (mains cooler) are used for automobiles. In the cold For example, heat sinks made of copper pipe with inserted aluminum fins are used in air conditioning technology. For PCs and notebooks, finned heat sinks in combination with heatpipes have prevailed. However, the finned heat sinks used to date have disadvantages. Thus, only a slight structural and / or mechanical stability is given. In addition, thin slats bend easily. A heat sink consisting of flat straight blades offers little shear and torsional rigidity.

In view of the above, disadvantages of the known and conventional convection-cooled housings and the heatsinks used are to be avoided. Accordingly, a silent and low-emission convection cooling for electronic and / or electrical components is provided. This should require less raw material than conventional convection cooling. A high tolerance in the production should be possible, so that the Konvektionskühlung be suitable for a mass production, thus be scalable both in the production (number of units, procedures) as well as in the application (power, size, design). In this case, slats are preferably used as a heat sink, which have improved structural and / or mechanical stability. The slats should be as versatile as possible. Accordingly, lamellae inserted for a housing must be provided, which, despite the low material thickness, are sufficiently rigid to form a solid housing surface. It should also be made possible that the electronic and / or electrical components should not only be kept within the specified working temperatures, but have a longer life expectancy compared to the conventional forced cooling, whereby the aging process caused by thermal stress can be reduced.

The object of the present invention is accordingly to provide a convection-cooled housing for electronic and / or electrical components, heat sinks for such a housing, and a manufacturing method for these heatsinks, which are structurally and / or mechanically stable, silent, low-emission, cost-effective, scalable convection cooling enable. This object is solved by the subject matters of the independent claims. Preferred embodiments are subject of the dependent claims.

According to the invention, a convection-cooled housing is provided for cooling electrical and / or electronic components. The housing (100) comprising:

a plurality of openings at the top of the housing; and

a heat sink comprising at least one fin, wherein the heat sink is disposed at the top of the housing relative to the plurality of openings so that an air flow through the housing is directly aligned with the overlying fin.

The fins of the heat sink may be mounted on the top of the housing perpendicular to the openings on the top of the housing so that the air flow from the openings is shared and flows directly along the surface of the fins.

Preferably, the heat sink comprises a plurality of fins, wherein the fins are arranged at a distance of 6 to 20 mm parallel to each other in the heat sink.

Further preferably, the lamellae are arranged at a hexagonal width of 20 mm and a distance through the deep-drawn hexagonal structure effectively 10 mm apart from each other parallel to each other in the heat sink.

Accordingly, the fins are spaced at a maximum distance from each other. Although a larger distance means more effectiveness per area, but also less area and thus fewer fins. When designing a heat sink, a balance is made between effectiveness per area and area use. Due to the available volume on the top of the housing is a very material-saving, the effectiveness per area preferable balance to choose from. Preferably, openings are provided in the underside of the shell of the housing, which are arranged relative to the openings at the top, so that a natural convection direction of the air is made possible in the housing.

Further preferably, the openings in the bottom of the housing are arranged relative to the openings at the top of the housing, that the openings are arranged on the underside similar to the openings on the top and / or have a comparable overall cross-section.

Preferably, the openings are formed as slots. Preferably, the elongated holes have a length from the rounded slots from the radius center to the center, which corresponds to the length of a hexagonal edge length of a fin of the heat sink. Furthermore, the oblong holes preferably have a width which corresponds to four to six times the thickness of a lamella, for example 0.8 mm to 4 mm. So that the stability of the upper side of the housing is not impaired, the elongated holes are preferably arranged only below the vertical sections of the fins of the heat sink.

Preferably, the components are arranged relative to each other and to the heat sink so that a natural convection of the air in the housing is made possible. In this case, those of the components with the lowest load capacity in the intake air at the bottom in the housing and those of the components with the highest load capacity in the intake air are preferably arranged at the top in the housing.

According to the invention, a heat sink is provided for cooling electrical and / or electronic components. The heat sink comprising:

at least one of a sheet metal strip integrally formed lamella, wherein the lamellar segments of the lamella have a hexagonal shape.

Preferably, a plurality of fins is provided, wherein the fins are arranged parallel to each other to a rectangular grid of a plurality of To form hexagonal lamellar segments.

Preferably, the heat sink is arranged on the upper side of a housing.

According to the invention, a method is provided for producing a lamella of a heat sink for cooling electrical and / or electronic components. The method comprises:

spaced slitting of a metal strip standing horizontally on the thin edge;

Pressing or pressing of the lamellar segments formed by slitting in hexagon shapes.

The length of the rounded slots from the radius center to the center corresponds to the length of a hexagon edge length in the metal strip of a lamella. The slots preferably behave towards the hexagons and / or the hexagon width approximately 1.7 to 1. With an exemplary hexagonal width of 20mm, this results in a slot length (unwound hexagonal half) of 34mm. The entire hexagonal honeycomb lattice of a lamella can thus be considered as consisting of uniform lamellar segments, each with a hexagon and a straight section with the length of the edge length of the hexagon. The resulting overall length of such a segment is 35mm, with an exemplary hex width of 20mm.

Preferably, the pressing comprises

a (spatial) pulling up (or a thermoforming) of the part of the lamellar segment above the respective slot in one direction; and

a deep drawing (as a type of sheet metal forming) of the part of the lamellar segment below the slot in the opposite direction.

Preferred embodiments will now be described by way of example with reference to the accompanying drawings. It is noted that even though embodiments are described separately, individual features thereof are additional Embodiments can be combined. Show it:

Figure 1A shows a schematic structure of a conventional industrial housing, which is passively cooled.

FIG. 1B shows a schematic structure of a convection-cooled housing according to the invention.

FIG. 2A shows a side view of an exemplary convection-cooled server housing according to the invention.

FIG. 2B shows a plan view of an exemplary convection-cooled server housing according to the invention.

Figure 3A shows a metal strip from which a blade according to the invention can be made.

Figure 3B is a plan view of a blade according to the invention.

Figure 3C is a side view of a blade according to the invention.

Figure 4 shows a tool for producing a blade according to the invention.

5 shows a screenshot of a measurement scenario for measuring the cooling efficiency of the heat sink according to the invention.

FIGS. 6A to 6E are screenshots of measurement results of a first test for measuring the cooling capacity of a heat sink according to the invention.

FIGS. 7A to 7E are screenshots of measurement results of a second test for measuring the cooling capacity of a heat sink according to the invention. FIG. 1A shows a conventional housing 10 with a heat sink 18 for cooling the circuit boards 14 and / or components 16 contained in the housing 10 (also referred to in the following as components 14, 16). The housing 10 may include a shell 12, for example, be encased therewith. The heat sink 18 may be attached to the top of the housing as shown in FIG. 1A.

A disadvantage of such a conventionally passively cooled housing 10 may be that a heat accumulation forms in the interior of the housing. The heat accumulation in the interior of the housing 10 may arise because a heat sink made of extruded profile can only be flowed through in one direction and is otherwise plate-shaped. A smaller fin spacing of extruded heatsinks is chosen to optimize material usage and cooling performance. Due to the massive bottom plate of a strand cooling element 18, a large finned spacing would consume considerable resources with a heat sink made of metal strips. Instead, usually a smaller heat sink 18 is selected with denser fins, a lighter, airy heat sink with multiple flow directions is not feasible in Strangpro filverfahren. Although the cooling body 18 may have a relatively large surface, because a smaller heat sink 18 with very dense fins has a larger total surface area than a large heat sink with generous fin spacing, which is only badly utilized. A poorer utilization can result from the fact that the temperature resistance of the heat sink 18 decreases with the air velocity and the distance of the cooling surfaces to each other. The former is due to the fact that the air as a heat-dissipating medium has a larger (heat capacity) at higher speed, the latter being due to the larger radiation angle to the surrounding space due to the larger louvre distance, which dissipates more heat energy in the form of infrared radiation to the surrounding space than from Accordingly, distributed over a surface, efficiency increases with increasing lamellar spacing, which means that the board 14 can only be cooled insufficiently, resulting in only a small air flow in a solid body of the housing 10. In order to ensure sufficient cooling, In accordance with a fan in combination with the heat sink 18 must be used to air through the housing 10 to press.

FIG. 1B shows a schematic longitudinal section through a housing 100 according to the invention with a heat sink 200 according to the invention. The heat sink 200 comprises one or more fins 210 which are described with reference to FIGS. 3A, 3B, 3C and 4. In the housing, one or more boards 120 and / or one or more electrical and / or electronic components 130 (in the following also referred to as components 120, 130) are arranged. The housing 100 is accordingly suitable for receiving corresponding boards 120 and / or components 130. The housing 100 is, for example, a PC housing, a notebook housing, a server housing, a control and / or control cabinet.

The housing 100 is convection-cooled, so that an additional fan is not necessary. Nevertheless, to improve cooling, for example, in a more densely packed housing (with a high density of components), a fan may additionally be used. The fan generates a corresponding intake air for cooling the housing 100, in particular for cooling the one or more circuit boards 120 and / or electrical and / or electronic components 130 arranged therein. The fan can be used to increase a natural air flow that is generated by convection leads vertically through the housing. The housing 100 may include a sheet metal shell (e.g., a sheet steel shell) 110, for example, encased therewith. The heat sink 200 is disposed on the housing 100. Preferably, the heat sink 200 is disposed on the upper outer surface of the sheet metal shell 1 10 and close flush with the housing 100.

FIG. 2A shows a side view of a convection-cooled housing 100 with heat sink 200 according to the invention as described in FIG. 1B.

FIG. 2B shows a top view of a convection-cooled housing 100 with heat sink 200 according to the invention as described in FIG. 1B. Preferably, the components 130 and / or boards 120 are arranged in the housing 100 and / or the heat sink 200 is configured and / or arranged on the housing 100 (relative to the components 120, 130) that natural convection of the air in the housing 100 is made possible to fulfill the function of forced cooling, in particular for SMD components, but no fan is additionally required. Furthermore, a flow optimization is achieved. In other words, the pressure resistance in the housing is minimized (also called shape resistance) with a simultaneous maximization of the frictional resistance of the components 130 and / or the / the board (s) 120 (also referred to as surface resistance). The components 130 and / or circuit boards 120 are referred to collectively below as components 120, 130.

The printed circuit board (s) 120 and / or components 130 are preferably arranged in the housing 100 in such a way that a natural convection direction (namely from bottom to top) is not disturbed. For this purpose, 10 openings 140 are provided on the upper side 104 and / or on the lower side 102 of the housing 100 in the casing 1. The openings 140 in the top 104 of the housing may be in the form of elongated holes and may be aligned so that the air flow is focused directly on the overlying fins 210 of the heat sink 200. The openings 140 flow from below to a fin 210 and / or individual sections of a fin 210 so that the center of the air flow is directed to the underside of the fin 210 and the air flow is divided at the fin 210. In addition, the fins 210 of the heat sink 200 are spaced larger than in conventional housings. For forced-ventilated lamellar heat sinks, spacings of less than 2 mm are usual; for chilled radiators a distance of 2-10 mm is usual, usually less than 6 mm. In the case of the heat sink 200, a spacing of the fins 210 of greater than 6 mm is preferably provided. Accordingly, the advantages of greater fin spacing, which allow for improved thermal radiation, can be combined with the efficiency improvements of a closer mesh heatsink 200 that allows for better detachment of the laminar slip layer. For a given volumetric flow, a more dense mesh will provide better slip delamination. This is a linear effect, so everything that is close-meshed, even if it is only 0.1mm less, theoretically produces a slightly better sliding layer separation, so better heat transfer to the cooling medium. However, a more dense mesh of a heat sink 200 also creates a greater static pressure and allows less infrared radiation. By the flow of the fins 210 of the heat sink 200 is formed with large pitches, but has an air flow to a heat sink with a small fin pitch. Preferably, no lateral cutouts are provided in the shell 110 of the housing 100 in order not to unnecessarily swirl the natural air flow (also referred to as chimney effect) and / or to reduce it between the components 130 and / or blanks 120.

The components 130 and / or board (s) 120 are arranged in the housing 100 in the order of their thermal capacity, with components 120, 130 with lowest load capacity in the intake air below and components 120, 130 with the highest load capacity at the top in the housing. Hard-wearing components 120, 130 include, for example, hard disks (load capacity 0-60 ° C.). High-load components 120, 130 include, for example, voltage converters (capacitors rated up to 85 ° C or 105 ° C), processors (up to 95 ° C), and / or motherboard with chipset (rated up to 104 ° C). In addition, for the components with the largest waste heat of the heat sink 200 outside of the housing 100 or on the upper outer surface of the shell 1 10 are arranged to prevent adverse effects on the surrounding components 120, 130. Alternatively and / or additionally, a heat sink 200 may be arranged on the rear side and / or a side surface of the housing 100. However, the arrangement of the heat sink 200 on the top of the housing 100 is preferable to enhance the air flow through the housing 100 by convection. The arrangement on a side surface and / or the back of the housing 100 would mean the separation into two air streams, inside and outside, and on the one side and on the other side. Preferably, cooling structures and / or micro-cooling bodies within the housing 100 are avoided. Instead, there is a maximization of the air flow and / or the effectiveness of the heat sink 200, which is arranged on the upper side 104 of the housing 100. Furthermore, a surface coating of the element carrier (not shown) arranged in the housing 100, the components 120, 130 arranged thereon, and / or the fins 210 of the heat sink 200 with respect to a thermal emissivity can be selected. The emissivity of a black anodised aluminum part reaches an emissivity of up to 0.85, ie 85% of that of a perfect black body (ie the physically ideal thermal radiation source). Uncoated aluminum, on the other hand, usually only reaches an emissivity of approx. 0.05. Painting and powder coating are a poor choice of surface coating due to their insulating effect for heat conduction. It is preferable to choose a metallic coating such as, for example, black galvanizing and / or anodization instead of a coating and / or powder coating.

The heat sink 200 includes light slender vanes 210 as opposed to solid swaged forged, milled and / or extruded heat sinks. The fins 210 are arranged at the greatest possible distance from one another in the heat sink 200, so that a maximization of the cooling capacity per use of material is made possible. Preferably, a compromise is sought for the available volume of construction from the largest possible fin spacing and sufficiently large cooling surface. This distance is higher by a factor of 2 to 10 than by force-cooled heat sinks and by a factor of 1.5 to 4 higher than with conventional extruded passive heat sinks. The heat sink 200 is arranged on an outer side, preferably the upper side, of the housing 100. Copper heatpipes may be provided from the heat sink to connect power devices 130 (e.g., CPU).

Preferably, solder joints are provided substantially in the heat cycle of the housing 100, wherein only if necessary, if the mounting options would otherwise significantly affect the thermal grease is provided. With Wärmeleitpastenverbindungen then the contact pressure can be maximized. A Wärmeleitpastenverbindung (also referred to as thermal interface material), z. As thermal grease, but also pads or thermal tape is intended to the tiny gaps in the surface between components (eg chip or cap of the Chips) and the heat sink or the Wärmeleitbrücke to fill. For areas of several square centimeters, such as processors, a high contact pressure of over 300N is necessary to distribute the TIM. A high contact pressure also ensures that any manufacturing tolerances in the Wärmeleitbrücke not lead to a tilting of the Heatsinks and thus fatal air gap. It can be avoided within the housing tilting (also referred to as air gap) by using flexible heat pipes. In the case of the arrangement and assembly of the components 120, 130 therein, oscillating components 120, 130 (eg a hard disk) can be decoupled in order not to increase a noise emission at the expense of the improved convection cooling.

Preferably, the shell 1 10 of the housing 100 can be made predominantly of stamped parts made of thin sheet, so that a scalable production of prototypes up to mass production is possible. The energy consumption compared to milling, die casting, extrusion and / or injection molding is much lower in the stamping process. Thermal bridges in the housing 100 may be formed of individual heat pipes with soldered coldplates. The relative mechanical flexibility of these solutions over solid Wärmeleitverbindungen allows greater tolerances in sheet metal parts for and / or in the housing 100 and thus a cost, location-independent production of the housing and / or the heat sink 200 for the housing 100th

Preferably, the housing 100, in particular the shell 110 of the housing 100 made of sheet metal, preferably made of sheet steel, so that an electromagnetic compatibility is improved. The arranged in the housing 100 components 120, 130 are very well shielded against external damage in the housing despite cooling holes 140, because the openings 140 are provided only at the top and / or on the underside of the shell 1 10 of the housing 100, the openings 140th small slots are (preferably with a length of 17mm and a width of 4mm) and / or the openings 140 are provided in the shell 140 at the top of the housing 100 below the heatsink 200 disposed above. The significantly higher heat capacity and thus inertia of the heat sink 200 compared to the forced-ventilated heat sink by means of fans ensures a considerably longer warm-up and / or cool-down phases of the components 120, 130. This reduces the thermal stress that is required for accelerated aging of C4 / flip-chip devices. Packages and / or cold solder joints on BGA components is responsible. Furthermore, a conventional coupling of an intelligent speed control of the forced ventilation by means of a fan to the temperature or utilization of a single larger component (eg to the CPU) contradicts the air flow actually required for the cooling, in particular of SMD components on a circuit board. This creates additional thermal stress in the plastic or ceramic housing of a smaller component.

FIGS. 3A, 3B and 3C show an exemplary fin 210 according to the invention which, alone or in combination with one or more of such fins 210, forms a heat sink 200 for a housing. Preferably, a plurality of fins 210 may be spaced parallel (preferably at a distance of 20 mm) so as to form together a rectangular grid of juxtaposed louver segments 212 which forms a heat sink.

Figure 3A shows a rolled metal, for example a sheet, preferably aluminum or copper alloys having a high coefficient of thermal conductivity, most preferably AL5052 / ISO AlMg2.5, from which a fin 210 can be made. For this purpose, as shown in Figure 3A horizontally standing on the thin edge metal strip is slotted several times spaced (for example, 250-300 mm, preferably 287 mm total length, 15-25mm, preferably 20 mm wide, 35-50 mm, preferably 46.5 mm Slot length, 8-15 mm, preferably 12 mm slot spacing). Thereafter, the portions of the blade 210 formed by the slits 210 are pressed in hexagonal shapes, shortening the overall length of the output blade 210 as shown in Fig. 3A. The hexagon shapes can be generated in parallel or in succession. In creating the hexagon shapes as shown in Figs. 3B and 3C, the portion of the blade 210 above the respective slot is pulled up in one direction and the portions of the blade 210 below that slot in the opposite direction (spatially) deep-drawn, so that viewed from above (see Figure 3B) each yields a hexagon. The hexagonal shapes thus form the lamellar segments 212 of the generated lamella 210. Accordingly, the parts of the lamella 210 above and below the slot are simultaneously thermoformed in both directions, independently of which spatial axis the forming process takes place.

FIG. 3B shows a correspondingly manufactured lamination 210 having a multiplicity of

Slat segments 212 in a plan view. FIG. 3C shows a correspondingly produced lamella 210 with a multiplicity of lamellar segments 212 in a side view. The lamella 210 is preferably a lamination 210.

Because lamellae 210 are manufactured as described with reference to FIGS. 3A-3C and form a chain of hexagons, that is to say lamellae segments 212, lamellae 210 results in a substantially increased angular stability relative to the baseplate of a housing into which lamella 210 is inserted can, to form alone or in combination with one or more fins 210, a heat sink 200. For the housing.

In contrast to conventional so-called honeycomb honeycomb (honeycomb), in which a hexagonal strip is composed of two metal strips, double plate wall thicknesses, welding and / or bonding of the metal strips are avoided in a blade 210 shown. In contrast, a double material thickness would lead to more weight and / or material use without profit on cooling surface and a process-consuming joint. Rather, in the (parallel) juxtaposition of the lamellae 210 for producing a heat sink gaps, which are not visible from above, as they form a continuous honeycomb grid (see Figure 2B), but obliquely from above show a deposition of the honeycomb to each other ( see FIG. 3C). Accordingly, only a lesser amount of material is necessary. FIG. 4 shows an exemplary tool 300 for producing a lamella 210. Preferably, lamellae can be produced by means of the tool 300 shown. The tool 300 is composed of one or more tool parts 302-320 and enables the production of lamellae 210 from slotted sheet metal strips.

As shown in FIG. 4, laminations 210 are made not by simply canting and / or deep-drawing the edges at the slots, but by one or more different movements of the two press jaws 310, 312, 314, 316 relative to the retainer (not shown) to press the blade into the tool so that the slot is exactly at the height of the transition between the two dies 310, 312, 314, 316 and not over it and / or a precise consideration of the shortening factors (the geometric shortening from the hexagon, as well as the compression , Material displacement and elongation in some corners, about 0.69x the original sheet length relative to the slotted portion of the lamella). The pressing jaws 310, 312, 314, 316 are held in a guide 302 (or an external linear guide) and pressed against each other by a respective threaded block 306, 308 (or a pneumatic cylinder or a toggle) on a thread 304 around the lamellae segments 212 to form the metal strip. The lower pressing jaws 310, 312 and the upper pressing jaws 314, 316 are covered by a respective cover plate 318, 320.

Slats 210 may be made as follows from sheet metal strips shown in FIG. 3A.

In a manufacturing process, a deep drawing tool for a respective slat segment, which results from the respective slot, a slat 210 is used, wherein for the respective slat segment 212 each two jaws are used. For each fin segment 212, the fin 210 is alternately inverted and deep drawn by the jaws. The method described above can be automated by using more than one thermoforming tool (preferably one thermoforming tool per slot of a sheet metal strip for a slat 210) simultaneously (or in a defined sequence) and corresponding slat segments 212 simultaneously (or in the defined sequence) ) as described above to create the hexagons in the fin 210. Accordingly, the thermoforming tools described above are used, but are mounted on a common linear guide and / or can be moved by a respective own linear actuator per tool on the axis. In a defined serial sequence of pressing operations, the jaws would be mounted tools according to the reduction factors of the preceding single section and the pressing process to be performed sequentially. A common linear guide would not be necessary, but a positioning that prevents a longitudinal displacement of the blade between the pressing tools. An insert mechanism could consist of a magazine and slide which presses the lamella in all five pressing tools. The ejection could take place via narrow slides between the individual pressing tools.

In addition, lamellae 210 can be made of endlessly long sheet metal strips of a roller by means of gears with trapezoidal teeth, for example, be formed. The number of segments of the lamella no longer depends on the number of pressing tools in a complete tool.

FIG. 4 shows a simplest version of a pressing tool which can deep-draw only one segment per operation.

Referring now to Figs. 5, 6A to 6E and 7A to 7E, there are shown two results of tests on the cooling performance of a heat sink described with reference to Figs. 1B to 4 in comparison with conventional heat sinks.

The following figures show the effectiveness of a heat sink according to the invention (also referred to in the figures as "mesh" or "mesh cooling") conventional cooling solutions. In particular, for various cooling methods, the cooling capacity for a processor, a hard disk, a circuit board, a voltage converter and the measured at the top outside temperature of the housing was measured and the thermal cycles to which these components or components are exposed. The limit temperatures listed in the table below must be taken into account.

In FIGS. 6A-E and 7A-E, in order to compare the cooling capacity of a heat sink according to the invention with conventional heat sinks, a given housing is alternately provided with a heat sink according to the invention (respectively the "mesh" curve in all FIGS. 6A-E and 7A-E), an Intel Boxed cooler, so active, OEM solution (each with "boxed" designated curve in all figures 6A-E and 7A-E) and two different passive chillers made of aluminum extruded profile (each with "sträng 1" and "strand2" designated curves in all Figures 6A-E and 7A-E).

The following table lists measuring points and limit temperatures. In an office environment, room temperature can reach up to 35 ° C. The thermal load limit is therefore not an absolute value in ° C, but the differential temperature Delta T in ° K to the maximum ambient temperature of 35 ° C.

For the measuring method of the cooling performance of the heat sink to be compared, in addition to the integrated temperature sensors of the components, hard disk and processor, PT100 temperature sensor on the back of the board, voltage transformers, housing surface and attached to the intake air (ambient air). Recording was done using an Aquero5 LT transducer (+ -0.5 ° K) 7, the Aquasuite and CoreTemp programs for reading. From a running system, two load scenarios (Figures 6A-F and Figures 7A-F) are tested using the BurnlnTest program. All components of the system, processor, RAM, hard disk, network and I / O will be fully utilized for a short time. The temperature values are recorded using the test computer itself.

FIG. 5 shows a typical measurement scenario. The typical operating state of a server is the idle state with short peak loads. However, the cooling solution must also be sufficient in the limit range, ie at full load. To simulate this area and the effect of the thermal cycles that occur during normal server operation, two test programs have been designed:

- Testl: 10 seconds load, / 12 seconds rest - Number of cycles: 50 (see Figures 6A-6E)

- Test 2: 200 seconds load / 200 seconds rest - Number of cycles: 20 (see Figures 7A-7E)

Wherein the cycle numbers in the screenshots of the diagrams shown in Figs. 6A-E and 7A-E are cut to 45/19 because of the start-up time of the sensors and recording programs.

The test programs were started by batch script and therefore the measuring point distances are subject to slight fluctuations (+ -500 milliseconds).

The following hardware has been tested

Protonet housing 8

- Intel Xeon 1265LV2 2.5Ghz (runs measured on all 4 cores in Turbo at 3, lGhz, with

- one core at 3.5 GHz), max. 45W heat loss power (WVL)

- 2x 4GB SODIMM Kingston DDR3 1600 - Intel DQ77KB motherboard, mounted upright with the voltage transformers facing down

- 2x 2TB Seagate Pipeline 5900.2

Cooling:

o Heatsink according to the invention, also referred to as "mesh" consisting of aluminum fins black anodized, 3x 6mm heatpipes ("mesh")

Curve in FIGS. 6A-E and 7A-E)

o Intel boxed cooler (reference solution, 92mm active fan) (boxed curve in Figures 6A-E and 7A-E)

o Extruded profile Fischer Elektronik SK94 horizontally mounted on the housing, 3x6mm ("sträng 1" curve in Figures 6A-E and 7A-E) Heatpipes

(9.)

o extruded profile Fischer Elektronik SK94 mounted vertically on the backside, 3 x6mm heatpipes ("strand2" curve in figures 6A-E and 7A-E)

The selected test method is subject to the following restrictions, which are taken into account in the evaluation:

- For reasons of comparability, the case is always the same. Now the housing has a large number of ventilation openings at the top and bottom and feet that allow air to flow through the bottom. This is not the case for the average of actively cooled housings and industrial PC housings. It is to be expected that, in particular, the extruded-cooled housings benefit from this, because the components are cooled very well by the convection air flow. For horizontal mounting of the extruded profile heat sink, however, the top is completely closed and a heat build-up is likely.

- The SK94 extruded profile heat sink was chosen because it can be attached well to the Protonet housing and with 200 * 180 * 25mm has about the same dimensions as the mesh with 230 * 210 * 20mm. However, this extrusion heatsink weighs 2.4 times the mesh cooling (370g) at 897g and has a 2.2 times larger cooling surface (2866cm 2 vs 1318cm 2). In the evaluation it must therefore be taken into account that the thermal inertia and cooling capacity are not absolute, but in relation to the use of materials, energy production costs, weight and costs.

The first series of tests is shown in the screenshots of the diagrams in Figures 6A-6F for the respective components listed in the above table.

Figure 6A shows the result of the CPU (or processor) cooling. The cooling by means of a heat sink according to the invention (shown in the "mesh curve") shows on the processor a temperature characteristic similar to that of the Intel boxed cooler ("boxed" curve) Inertia, landing at similar values when in horizontal orientation but after warming-up, will have a significantly lower thermal resistance in the vertical orientation.

Figure 6B shows the result of PCB cooling. The cooling by means of a heat sink according to the invention (shown in the "mesh curve") achieves a slightly lower temperature resistance than the boxed cooler ("boxed" curve.) The horizontal extruded profile ("strand 1", "strand 2" curves) instead of the heat sink according to the invention creates a heat build-up and has a significantly higher temperature resistance.

Figure 6C shows the result of the VRM (or voltage converter) cooling. A similar picture as on the back of the board. By positioning the voltage transformers on the bottom of the housing, the temperature during cooling by means of a heat sink according to the invention (shown in the "mesh curve) is lowest, which directs the intake air by convection effect through the housing. A closed by the horizontal extruded profile housing can not cool the voltage converter sufficient.

Figure 6D shows the result of HDD (or hard disk) cooling. The Intel Boxed cooler ("boxed" curve) sucks its intake air through the hard drive bays and achieves the lowest temperature resistance here, the horizontally mounted extruded profile continues to supply marginal temperatures ("sträng 1" curve), whereby bas housing with vertical extruded heat sink (curve "strand2") reaches a lower temperature than the housing with horizontal extruded heat sink (curve "strangl") ,

Figure 6E shows the result of the case (or case surface) cooling. The surface temperature of the housing is naturally higher with external passive coolers ("strangl", "strand2" curves) than with the boxed curve. Cooling by means of a heat sink according to the invention (shown in the "mesh curve") achieves a somewhat lower one Surface temperature than the horizontally mounted passive heat sink.

The second series of tests is shown in the screenshots of the diagrams in Figures 7A-7F for the respective components listed in the above table.

Figure 7A shows the result of the CPU (or processor) cooling. For longer cycles, more accurate statements about the temperature resistance and the height of the thermal cycles can be made. The amplitude of the cycles is greater in the case of the Intel Boxed cooler ("boxed" curve) than in the case of passive cooling ("strangl" "strand2" curves.) Both strand cooling element solutions have a long warm-up phase and very shallow cycles the "mesh curve") has a lower thermal cycling amplitude while still providing comparable thermal resistance to the Intel Boxed cooler.

Figure 7B shows the result of PCB cooling. With regard to the board temperature, cooling by means of a heat sink according to the invention (shown in the "mesh curve") with the Intel boxed cooler achieves comparable average values, but a significantly lower thermal amplitude.

Figure 7C shows the result of the VRM (or voltage converter) cooling. The Spannungswandlertemperatur is low through the downwardly open housing, the The thinnest thermal cycles are achieved by cooling using a heat sink according to the invention (shown in the "mesh curve"). Only the housing with horizontal extruded heat sink is again significantly higher ("sträng 1" curve), whereby the housing with vertical extruded heat sink (curve "strand2") reaches a lower temperature than the housing with horizontal extruded heat sink (curve "sträng 1").

Figure 7D shows the result of HDD (or hard disk) cooling. At longer temperature cycles, the boxed curve will perform less well, which could be related to the processor waste heat dissipated inside the case of the Intel Boxed Cooler.

Figure 7E shows the result of the case (or case surface) cooling. As expected, the surface temperature of the case continues to be higher than that of fan cooling, since the temperature sensor is practically mounted directly on the processor heat sink (or vertically mounted on the top of the vertical extrusion heat sink).

The developed (passive) cooling by means of a heat sink described with reference to Figures 1B to 4, in which a heat sink of laminations is attached to the top of the housing and the intake air is passed through the housing, has proven in the test over known methods. The method achieves comparable processor cooling performance as the reference solution with an active fan. The cooling of the peripheral components is better than with the reference solution. When cooling with an Intel Boxed cooler, therefore, the use of an additional case fan is recommended. The thermal stress to which the components are exposed is lower with the cooling according to the invention because the cooling is generally slower than with active cooling. Compared with a closed industrial housing, the many slot-shaped openings on the bottom and top have proven themselves. The same housing with an externally mounted extruded heat sink at the rear for processor cooling achieved in the test the lowest processor temperatures, but with disproportionately larger weight, surface and material usage compared to the cooling according to the invention. The low temperature of the voltage transformers, the direct at the suction openings show how the temperature gradient creates a vertical flow of air through the housing. The hard drives, which are currently mounted centrally in the housing, could also be mounted further down in the next revision, in order to further improve their cooling with intake air and to separate them from the upper zone of processor and board waste heat. A further reduction of the component temperatures in a cooling according to the invention can thus be generated by flow improvements and improved positioning of the components. As the test with a voluminous extruded heat sink shows, a further reduction of the thermal amplitude and thus a longer life expectancy of the components can only be achieved by a larger heat sink mass.

LIST OF REFERENCE NUMBERS

10 housing

12 housing wall

14 board

16 electronic and / or electrical component

18 heat sinks

100 housings

102 top of the housing

104 Bottom of the housing

110 housing wall

120 board

130 electronic and / or electrical component

140 openings

200 heatsinks

210 lamella

212 slat segment

300 tool for manufacturing lamellae

302-320 tool parts

Claims

claims

A convection cooled housing (100) for cooling electrical and / or electronic components (120, 130), the housing (100) comprising:

a plurality of openings (140) on the top (104) of the housing (100); and

a heat sink (200) comprising at least one fin (210), wherein the heat sink (200) is disposed at the top (104) of the housing (100) relative to the plurality of openings (140) such that air flow through the heat sink Housing (100) is aligned directly on the overlying blade (210).

2. Housing (100) according to claim 1, wherein the heat sink (200) comprises a plurality of fins (210), wherein the fins (210) are arranged at a distance of 6 to 20 mm parallel to each other in the heat sink (200).

3. Housing (1009 according to claim 1 or 2, wherein in the bottom (102) of the shell (110) of the housing (100) openings (140) are provided which relative to the openings (140) on the top (102) are such that a natural convection direction of the air in the housing (100) is made possible.

4. Housing according to one or more of the preceding claims, wherein the openings (140) are formed as slots.

5. Housing according to one or more of the preceding claims, wherein the components (120, 130) relative to each other and to the heat sink (200) are arranged so that a natural convection of the air in the housing (100) is made possible.

A heat sink (200) for cooling electrical and / or electronic components (120, 130), comprising:

at least one lamella (210) formed in one piece from a metal strip, wherein the lamellar segments (212) of the lamella (210) have a hexagonal shape.

The heat sink (200) of claim 6, comprising:

a plurality of laminations (210), wherein the laminations (210) are arranged parallel to one another to form a rectangular grid of a plurality of hexagonal laminar segments (212).

8. The heat sink according to claim 6 or 7, wherein the heat sink (200) on the upper side (104) of a housing (100) is arranged.

9. A method of manufacturing a fin (210) of a heat sink (200) for cooling electrical and / or electronic components (120, 130), comprising:

spaced slitting of a metal strip standing horizontally on the thin edge;

Squeezing the lamellar segments (212) in hexagonal shapes created by slitting.

10. The method of claim 9, comprising pressing:

Pulling up the part of the lamellar segment (212) above the respective slot in one direction; and

Deep drawing the portion of the louver segment (212) below the slot in the opposite direction.