Cooling device for electrical or electronic devices

0001The invention relates to a cooling apparatus for electrical or the electronic components in the preamble of Claim 1 genus said.

0002In a known cooling device (EP-A-0696160) similar Art, the rib-like cooling elements made of thermally well conductive material in the slit-like grooves of a base plate anchored that fasten the electric to be cooled or electronic components used. Anchoring the rib-like cooling elements in the slit-like grooves carried out by pinching by an elongated piece of wire in the region of the end of adjacent profile legs, ie the Profile foot, the rib-like cooling element is pressed, that the band-shaped material of the cooling elements in the region of this Ends is pressed against the longitudinal walls of the longitudinal grooves. Around improve anchorage, is also provided, the longitudinal grooves dovetailed form. In addition, it is proposed groove-like indentations in the longitudinal grooves sidewalls provide.

0003In addition, it is known (EP-A-0483058), the areas to slit between adjacent longitudinal grooves and after Inserting formed as hollow bodies, the cooling elements Base material in the area of ​​the side walls of such longitudinal grooves so to press inward, that the ends of the cooling elements are clamped between the side walls.

0004The invention is based on the object by simple means for an even better anchoring of the rib-like cooling elements in the base plate without bending the projecting of this to provide parts of the cooling elements.

0005The invention is characterized in claim 1 and in sub-claims are preferred embodiments thereof claimed.

0006According to the invention, groove-like depressions in the Longitudinal grooves sidewalls formed in the free cross-section such and dimensioned such that during the shaping of the respective side part the profile foot no substantial bending deformation of takes place from the longitudinal groove projecting profile leg.

0007It is advisable for the groove-shaped recesses not rectangular in cross section, but in such a way curved extend to that a gradual transition from the substantially parallel side walls in the indentations and takes place within the depressions. The radius of curvature should about 0.5 to 1 times the strip thickness of the cooling elements, respectively. This is an optimal flow behavior during permanent deformation of the existing particular aluminum Cooling elements and indeed limited to the question Profilfußbereich achieved in the rheological sense. It recommends it is, when the cooling elements even in the longitudinal grooves in the area between the groove-shaped recesses and the base plate surface, through which they protrude, are supported laterally of parallel side wall sections of the longitudinal grooves and indeed in sufficient extent of at least 1 times the thickness of the band Cooling elements.

0008In addition, it is recommended that if the longitudinal grooves a Depth - in the base plate - between the 3- and 15-fold and a width between 5 and 20 times the strip thickness have cooling elements.

0009Particularly favorable conditions without changing the vertical Alignment of the rib-shaped cooling elements - vertically from the Baseplate surface spreading - are therefore achieved when the side walls of the longitudinal grooves in said vertical direction run, not so in contrast to the prior art arranged dovetailed, and if they are grooved Wells both at a distance from the groove base as are also spaced apart from the surface of the base plate. This is the danger of bending of from the base plate protruding portions of the cooling elements at its insertion, and Compression in the longitudinal grooves encountered. The distance between the center the groove-shaped recesses of the groove base should be between the 2- to 8-fold of the strip thickness of the cooling elements, respectively.

0010Incidentally, it is advisable, though not on the groove base abrupt transitions to the side walls of the longitudinal grooves present are but the rounded groove base with a radius of curvature merges into the sidewalls of the times 3 between the 1- to is the strip thickness of the cooling elements.

0011The transition of the side walls in the base plate surface and in the groove-shaped recesses having a curvature radius should occur between the 0.3 and 1 times the strip thickness the cooling elements is.

0012Particularly favorable results are achieved when for the material of the rib-shaped cooling elements, the base plate and the wire pieces of the permanent flow deforming Profile feet and jamming them serve in the longitudinal grooves, easily deformable, thermally highly conductive aluminum, for example, Pure aluminum is used. For the wire pieces can merchantable use aluminum wire.

0013Embodiments of the invention will now be based on the Drawing explained. They show:<dl tsize="16"><dt>figure 1</dt><dd>a cooling device according to the prior art;</dd><dt>Figures 2 and 3</dt><dd>Two embodiments of the invention in a schematic Side view;</dd><dt>figure 4</dt><dd>a cross section through a portion of a base plate, which is provided with longitudinal grooves for receiving cooling elements is;</dd><dt>figure 5</dt><dd>a greatly enlarged partial section of the area the anchoring of cooling elements in the longitudinal groove of the Base and</dd><dt>figure 6</dt><dd>another embodiment of the invention in schematic Cross-section.</dd></dl>

0014According to Figure 1 are made on the underside of a base plate 2 Aluminum, by two side walls 2a to a cross-sectionally approximately U-shaped profile is updated, electrical and electronic Components 1a, 1b, 1c attached, that heat up during operation and their heat in a simple way by means of the cooling device to 1 derived. Here, the base plate 2 with in Longitudinally extending grooves 4, into which the lower bent ends 3a of rib-shaped cooling elements 3 are inserted, protruding the upper ends 3b free. All Cooling elements 3 of the known cooling device consist of a meander-shaped aluminum strip. The attachment of the lower ends 3a of the cooling elements 3 in the longitudinal grooves 4 of the Base plate 2 takes place in this known example, by soldering.

0015In the case of the embodiment of the invention of Figure 2 two cooling elements 3 formed by the free legs a U-shaped strip of pure aluminum. The two legs connecting webs of the cooling elements 3 at the lower end thereof form a profile base 3 and are in longitudinal grooves 4 of the base plate 2 is inserted. Here, between the two legs of each U-shaped profile wire pieces 5 made of aluminum squeezed and deformed so by application of pressure, that the 3a-profile legs of the cooling elements 3 slightly laterally outwardly in the groove-shaped recesses 4a in the side walls of the longitudinal grooves 4c 4 are in permanent deformation.

0016In the constitution example of Figure 3 is shown in FIG 1 a meandering deformed strip of pure aluminum for the cooling elements 3 used. Again, the lower ends, ie the profile legs 3a within the grooves 4 of the base 2 so permanent deformation that the material of the cooling elements 3 in the groove-shaped recesses 4a on both sides of the longitudinal grooves 4 is formed by extrusion-binding. This press-fit technology not only leads to a production technology simple, but also secure anchoring of the cooling elements 3 within the base plate 2, but also a good heat transfer the material of the base plate 2 to the material of the cooling elements 3, so that the cooling function for cooling the electronic component 1c can be well satisfied.

00174 shows a part of a base plate 2 of the cooling device 1 shown in cross section. In this case, the side walls of the longitudinal grooves 4 extending in the longitudinal direction of groove-shaped recesses 4a. The longitudinal grooves 4 pull up to a depth of A the surface 2c of the base 2 into this. This surface 2c is a curvature radius R2 on the up vertically from the base plate 2 upwardly extending sidewall 2a of the cooling device 1. In the examples of Figure 4 are no cooling elements connected to the base plate. 2

0018In the enlarged embodiment of the invention of figure contrast, 5 is the lower end, so the profile base 3 a Cooling element 3 - for example, from 2 - 4 in the longitudinal groove the base plate 2 anchored by extrusion. The middle the groove-shaped recesses 4a in the side walls 4c of the Longitudinal grooves 4 are located at a distance B from the groove bottom 4b, which merges with a curvature radius R2 in the side walls 4c. The groove-shaped recesses in the side walls 4a 4c have a radius of curvature R1. Go addition the side walls 4c rounded to the surface 2c of the base 2 with a radius of curvature of R3 above. Between the two Legs of the U-shaped component which the two cooling elements 3 forms, is in the area of ​​the profile base 3 at the bottom End and hence the longitudinal groove 4 a wire piece 5 is pressed. By applying pressure to the wire piece 5 this is the extent consistent deformed to the material of the cooling elements 3 in the region groove-shaped recesses 4 deformed in this engagement in, without protruding from the base plate 2 parts of are rib-shaped cooling elements 3 deformed or bent. The deformation is an extrusion. The groove-shaped recesses 4a penetrate into the depth between the E 0.2 times and 0.8 times the strip thickness C in the base plate 2 a. The length F of the parallel side wall portions between the surface 2c of the base plate 2 and the transition 4a should the groove-shaped recess between the 0.8 times and 3 times the strip thickness C.

0019In this example, the following dimensions, connections are preferred:<sl><li>A = 5.0 mm</li><li>B = 2.5 mm</li><li>C = 1.0 mm</li><li>D = 7.0 mm</li><li>E = 0.2 mm</li><li>F = 0.4 mm</li><li>R1 = 0.8 mm</li><li>R2 = 2.0 mm</li><li>R3 = 0.5 mm</li></sl>

0020Also, in the embodiment of Figure 6, a further Modification of the invention, a good resistance against tearing out of the cooling elements 3 of the longitudinal grooves 4 achieved by the profile foot hollow shape 3a of thin, here Cooling elements 3 by upsetting forces in the in this For example a slightly larger radius of curvature R1 and / or greater penetration depth E having groove-shaped recesses 4a are in compressed. This can be done by the fact that the hollow box-shaped cooling elements 3 of a guide tool shall be taken and injected into the longitudinal grooves 4 such that the projects out of the base plate 2 parts of the cooling elements 3 does not deform. The management tool is in this Example (not shown) in the cross-sectional comb-like manner so that the engage teeth of the comb between adjacent cooling elements 3 and support the walls there.

0021It has been shown that material thicknesses or strip thicknesses C between 0.5 mm and 1.5 mm for the cooling elements 3 are particularly have proven. In the case of using materials such as Al result good forming characteristics for molding in the groove-shaped recesses 4a.