EP1887303A2 - Heat exchanger and method for manufacturing same - Google Patents

Abstract

An automotive heat exchanger (2) has main sections (1) consisting of a folded metal ribbon of alternating thin (1.1) and thick (1.2) sections. The thick sections are each folded several times, forming chambers adjacent to the thin sections. In a process to manufacture the heat exchanger, several metal sections (1), assembled at 90 degrees to the adjacent section.

Description

The invention relates to a heat exchanger for exchanging heat between two or more media. Moreover, the invention relates to a method for producing such a heat exchanger and a possible use of such a heat exchanger.

Heat exchangers for exchanging heat are known from the prior art. The production of such heat exchangers is usually very expensive, since a large number of parts must be joined together. Essential components of a heat exchanger - also called heat exchanger matrix - which form its core structure for heat exchange between at least two media, such as pipes, sheets and ribs are usually soldered together, welded together, mechanically joined together or glued together. These joining methods are very time-consuming and therefore expensive.

For simplicity, heat exchangers and corresponding production methods are known in the prior art, in which the replacement matrix is produced in one step by extrusion (extrusion). An exchange matrix produced in this way is known, for example, from US Pat DE 10 2004 011 354 A1 known.

The invention has for its object to provide a method for producing a heat exchanger and such a heat exchanger, which is particularly easy and inexpensive to produce.

The object is achieved by a heat exchanger according to the features of claim 1. With regard to the manufacturing process, the object is achieved by the features of claim 17.

Advantageous developments of the invention are the subject of the dependent claims.

The heat exchanger according to the invention comprises a base element, which is formed from a metallic strip of tape with alternating thin and thick sections, wherein the thick sections are respectively repeatedly deformed such that in the region of the thin sections cavities are formed. It is formed by simply forming a single endless metal strip or sheet metal strip several times in a single manufacturing step, a heat exchanger, which is designed in particular as a so-called micro-heat exchanger with very narrow flow channels. The single base element contains all components required for a heat exchange, such as flow channels, which are formed by the cavities, and adjacent exchange surfaces. In addition, such a trained heat exchanger is particularly variable. For example, by varying the length and width of the thin and thick portions of the tape strip, the heat exchange and thus the performance of the heat exchanger can be specified.

In a particularly preferred embodiment, the thick sections are formed such that alternately segments with thick sections and segments with thin and thick sections arise, which are arranged parallel to each other. In a further embodiment, the thick sections are reshaped in such a way that alternately segments with thin sections which are arranged parallel to one another are formed.

To form flow channels, the thick portions of the tape strip are each kinked several times and alternately by 180 °. The length of the thick sections is greater than the length of the thin sections. As a result, the thick sections completely surround the thin section, wherein the height of the flow channel corresponds to the difference between the thin and thick band region or band segment. In one possible embodiment, the segments with thin and thick sections each have at least two thick sections, between which the thin section is arranged. As a result, the respective segment has a u-shape, through which cavities are formed by abutment of thick segments in the folded, folded or kinked state of the tape strip, which serve as flow channels.

In a further embodiment, the tape strip has a varying tape thickness in a range of 0.3 mm to 1.2 mm with alternating thin and thick sections with uniformly thin tape thickness of 0.3 mm to 1.18 mm or uniformly thicker tape thickness of 0 , 32 mm to 1.2 mm. The cavities preferably have a height of 0.02 mm to 0.2 mm (also called channel or gap width) and a length of 3 mm to 5 mm. The width of the cavity corresponds substantially to the width of the tape strip.

Expediently, in the formed state of the tape strip, the segments with thick sections form dividing walls, which in each case separate two successive segments with thin and thick sections and resulting cavities from one another. As a result, additional separate partitions or dividing sheets can be omitted within a primitive. In addition, with a multiple overlaying of several basic elements, an exchange matrix can be formed without conventional separate partitions between the basic elements by delimiting the thin sections on both sides by thick sections. This allows a high heat transfer coefficient in conjunction with good heat conduction in the heat transfer direction.

In a further embodiment, the tape strip on each end of several adjacent thick sections. In the deformed, for example, folded state of the tape strip form the outer segments with only constant thick sections closed Ends that are provided as profiles, for example, for mounting or attachment.

In an advantageous embodiment, the varying strip thickness is formed by introducing a predetermined surface structure. For example, the surface structure by rolling, etching, milling, punching and / or spaces can be introduced. Due to the varying strip thickness arise after forming, z. B. folding, the tape strip cavities, which have a corresponding channel height (also called channel or gap width) as flow channels.

For a sufficiently good sealing of serving as flow channels cavities to the outside and inside of the tape strip is solder coated by at least one band side, so that the adjacent segments are mutually positively and materially connectable. In addition, a solder coating at least on one side, z. B. on the bottom or top of the folded tape strip, the attachment of the base element in the folded state serve on a bottom plate. Alternatively, the base member may be glued to the floor panel or secured in any other suitable manner. Instead of the solder coating of one of the sides of the base member, the bottom plate may be provided with a solder coating. Preferably, the base element is in the deformed state from the bottom and / or from the top fluid-solderable solderable.

In a further advantageous embodiment, a plurality of basic elements are arranged one above the other. This allows in a simple manner in the counter and / or direct current direction, wherein one of the basic elements in one direction and the overlying primitives in the other direction or all in the same direction are flowed through by a medium with different temperatures or different media. In a staggered by 90 ° arrangement of the superposed basic elements a cross-flow heat exchanger with two or more crossed streams is possible in a simple manner. Conveniently, the superposed basic elements are fluid-tight with each other connectable. For this purpose, for example, the respective base element is one-sided, in particular on the bottom side, or solder-coated on both sides.

With regard to the method for producing the heat exchanger, a metallic strip of tape is punched out or cut out of a metallic endless strip as the basic element. Subsequently, a predetermined surface structure is introduced, for example by etching, cross-rolling or milling, so that the tape strip alternately has thin and thick sections. By repeatedly forming, for example, folding or folding, the thick portions of the tape strip are alternately arranged segments with thick sections and segments with thin and thick sections parallel to each other, so that in the region of the thin sections cavities are formed. In this case, the production of the basic element takes place in one step by multiple forming a single sheet metal strip. In this case, for example, a heat exchanger with particularly small channel widths or heights of 0.02 mm and larger produced. Such a micro-heat exchanger is due to the miniature version especially for cooling of electronic components, eg. B. for cooling a microprocessor.

Fig. 1

einen Wärmeübertrager, umfassend ein bandförmiges Grundelement im ungefalteten Zustand,

Fig. 2

schematisch den Wärmeübertrager gemäß Figur 1 im gefalteten Zustand,

Fig. 3

schematisch einen Wärmeübertrager mit mehreren übereinander angeordneten Grundelementen, und

Fig. 4,5

schematisch eine Verwendung eines Wärmeübertragers als Kühlelement für ein elektronisches Bauteil.

Embodiments of the invention will be explained in more detail with reference to a drawing. Show:

Fig. 1

a heat exchanger comprising a strip-shaped base element in the unfolded state,

Fig. 2

schematically the heat exchanger according to Figure 1 in the folded state,

Fig. 3

schematically a heat exchanger with several superimposed primitives, and

Fig. 4.5

schematically a use of a heat exchanger as a cooling element for an electronic component.

Corresponding parts are provided in all figures with the same reference numerals.

FIG. 1 shows an exemplary embodiment of a base element 1 of a heat exchanger 2. The base element 1 is a strip of metal, for example a metal strip. B. a thin sheet metal. FIG. 1 shows the base element 1 with varying strip thickness d _1,1 to d _1,2 in a range from 0.3 mm to 1.2 mm in the unfolded state. In this case, the basic element 1 is divided into longitudinal sections alternately into thin sections 1.1 and thick sections 1.2. Both the thin sections 1.1 and the thick sections 1.2 have an associated constant strip thickness d _1.1 or d _1.2 . In one possible embodiment, the strip thickness d _{1.1 of} the thin sections 1.1 is in a range of 0.3 mm to 1.18 mm; the strip thickness d _1.2 in a range of 0.32 mm to 1.2 mm.

The base element 1 is punched or cut, for example, from an endless belt. The endless belt is in particular a metal band made of a good heat-conducting metal, for. As aluminum, a collar metal, such as copper or brass. To form the strip of tape with varying strip thickness d _1.1 to d _1.2 , a given surface structure is introduced on one side, for example by transverse rolling, etching, milling, broaching or in another suitable manner. That is, the base element 1 has a lower, substantially flat hinge side 1.3 and an upper hinge side 1.4 in serrated or crown shape. In addition, the base member 1 of the lower band side 1.3, for example, solder coated. Since the solder is applied to the lower flat hinge side 1.3 of the base member 1, a running of the cavities formed in the thin sections 1.1 on the upper hinge side 1.4 with solder is avoided.

In order to form flow channels for the heat exchanger 2, the base element 1 is in each case repeatedly deformed in the thick sections 1.2 at predetermined forming edges 3, in particular folded or folded. The forming edges 3 are folds on which the bent or folded sections 1.2 are pressed together. For a multiple forming the thick sections 1.2 whose length l _{1.2 is} greater than the length l _1.1 of thin sections 1.1. In this case, the thick sections 1.2 are formed several times such that alternately segments 4.1 with thick sections 1.2 and segments 4.2 with thin sections 1.1 and thick sections 1.2 are arranged parallel to each other and cavities 5 are formed in the region of the thin sections 1.1. Preferably, the thick sections 1.2 are each bent several times alternately by 180 °. This results in a side view of the base element 1, as shown in Figure 2, a meandering shape. As a result of the solder applied to the lower band side 1.3, the segments 4.1 and 4.2 immediately adjacent to one another are connected to one another in a material-and-form-fit manner. Not shown in Figure 2 distribution boxes, which are placed on the side surfaces of the heat exchanger and the distribution or collection of each fluid to the base elements 1 are used.

To form the cavities 5, the segments 4.2 with thin and thick sections 1.1 and 1.2 each have at least two thick sections 1.2, between which the thin section 1.1 is arranged. The edge-side sections 1.2 and the thin section 1.1 of the segments 4.2 are designed in such a form and size that cavities 5 with a height h ₅ of 0.02 mm to 0.2 mm and a length l ₅ of 3 mm to 5 mm formed are. In addition, the cavities 5 have a width b _{1 of} the base element 1 and thus of the tape strip corresponding width b ₅ . By applying solder only on the lower band side 1.3, the cavities 5 are kept free of solder during the forming.

By repeatedly forming the thick sections 1.2, these form in the formed state of the tape strip consistently thick segments 4.1, which serve as partitions between two consecutive segments 4.2 with thin and thick sections 1.1 and 1.2. Thus, the upwardly open cavities 5 are covered by the thick segments 4.1 and successive cavities 5 separated from each other.

End several segments 4.1 are provided with only thick sections 1.2. That is to say, the base element 1 comprises at the edge in each case a plurality of adjoining thick sections 1.2. This results No accumulations of cavities 5 at the edge, which are used to hold brackets or attachments or as profiles. For this purpose, the tape strip on the edge side a plurality of sections 1.2 with the same thickness d _1.2 .

In addition, the base element 1 can be solder-coatable in a fluid-tight manner from the underside and / or from the top in the deformed state. This allows a fluid-tight connection of stacked primitives 1, as shown in Figure 3 in more detail.

In Figure 3 , a plurality of basic elements 1 are arranged one above the other. In this way, a so-called countercurrent or DC heat exchanger can be formed, in which the basic elements 1 are flowed through by fluids with alternating flow direction or with the same flow direction. Alternatively, the basic elements 1 can be arranged one above the other and offset by 90 ° to one another. As a result, a so-called cross-flow heat exchanger is formed.

Figures 4 and 5 show schematically a possible use of a heat exchanger 2 with a base element 1 as a cooling element for an electronic component. The basic element 1 is arranged in FIG. 4 in the folded state by way of example in a housing 6 and soldered or glued there, for example. For supplying or discharging a flowing through the base 1 cooling medium connecting elements 7 are provided on the edge. FIG. 5 shows the heat exchanger 2 according to FIG. 4 in a side view.

Claims (20)

Heat exchanger (2), comprising a base element (1), which is formed from a metallic strip strip with alternating thin and thick sections (1.1, 1.2), wherein the thick sections (1.2) are each repeatedly formed such that in the region of the thin sections (1.1) cavities (5) are formed. Heat exchanger according to claim 1, wherein alternately segments (4.1) with thick sections (1.2) and segments (4.2) with thin and thick sections (1.1, 1.2) are arranged parallel to each other. Heat exchanger according to claim 1, wherein alternately segments (4.1) with thin sections (1.2) are arranged parallel to each other. Heat exchanger according to one of the preceding claims, wherein the thick sections (1.2) are each bent several times alternately by 180 °. Heat exchanger according to one of the preceding claims, wherein the length ( _1.2 ) of the thick sections (1.2) is greater than the length ( _1.1 ) of the thin sections (1.1). Heat exchanger according to one of the preceding claims, wherein the segments (4.2) with thin and thick sections (1.1, 1.2) each have at least two thick sections (1.2), between which the thin section (1.1) is arranged. Heat exchanger according to one of the preceding claims, wherein the tape strip has a varying strip thickness (d _1.1 , d _1.2 ) in a range of 0.3 mm to 1.2 mm with alternately thin sections (1.1) with a consistently thin strip thickness (d _1.1 ) of 0 , 3 mm to 1.18 mm and thick sections (1.2) with a consistently thick strip thickness (d _1.2 ) of 0.32 mm to 1.2 mm. Heat exchanger according to one of the preceding claims, wherein the cavities (5) have a height (h ₅ ) of 0.02 mm to 0.2 mm and a length (L ₅ ) of 3 mm to 5 mm. Heat exchanger according to one of the preceding claims, wherein the cavities (5) have a width (b ₁ ) of the tape strip corresponding width (b ₅ ). Heat exchanger according to one of the preceding claims, wherein in the deformed state of the tape strip, the segments (4.1) with thick sections (1.2) form partitions, each two successive segments (4.2) with thin and thick sections (1.1, 1.2) and resulting cavities (5) separate. Heat exchanger according to one of the preceding claims, wherein the tape strip each end has a plurality of adjacent thick sections (1.2). Heat exchanger according to one of the preceding claims, wherein the varying strip thickness (d _1.1 , d _1.2 ) is formed by introducing a predetermined surface structure. Heat exchanger according to claim 12, wherein the surface structure by rolling, etching, milling, punching and / or spaces can be introduced. Heat exchanger according to one of the preceding claims, wherein the tape strip of at least one band side (1.3) is solder coated. Heat exchanger according to one of the preceding claims, wherein the base element (1) in the deformed state from the bottom and / or from the top is fluid-tight solderable. Heat exchanger according to one of the preceding claims, wherein a plurality of basic elements (1) are arranged one above the other. Heat exchanger according to one of the preceding claims, wherein a plurality of basic elements (1) are arranged one above the other and offset by 90 ° to each other. Heat exchanger according to claim 16 or 17, wherein superposed basic elements (1) can be connected to each other in a fluid-tight manner. A method for producing a heat exchanger (2) according to any one of the preceding claims 1 to 16, wherein from a metallic endless belt as the base element (1) a metallic strip of tape is punched or cut, in which a predetermined surface structure is introduced, so that the tape strip alternately thin and having thick portions (1.1, 1.2), and wherein then the thick portions (1.2) are repeatedly formed such that alternately segments (4.1) with thick sections (1.2) and segments (4.2) with thin and thick sections (1.1, 1.2) are arranged parallel to each other and in the region of the thin sections (1.1) cavities (5) are formed. Use of a heat exchanger (2) according to one of claims 1 to 18 for cooling electronic components.

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