Heat exchanger, especially for motor vehicles

A heat exchanger including a core with tubes and ribs between tube plates, two collecting tanks on the tube plates, and closure caps, all produced from solder-coated aluminum. The core includes a plurality of alternating flat tubes and ribs between spaced tube plates. Each collecting tank has two longitudinal walls joined to the longitudinal connection edges of one of the tube plates. The closure caps close ends of the collecting tanks, and have an edge aligned substantially parallel to the collecting tank walls. The edges of the longitudinal walls of the collecting tanks are arranged between the longitudinal connection edges of the tube plates, with protrusions on the edges of the longitudinal walls inserted in openings in the tube plates. The transverse connection edges of the tube plates have a contour cut-out matching the closure cap profile to form a tight and strong solder bond with the closure caps.

CROSS REFERENCE TO RELATED APPLICATION(S)

Not applicable.

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

1. Technical Field

The present invention relates to heat exchangers, and more particularly to aluminum motor vehicle heat exchangers having collecting tanks with side openings closed by closure caps.

2.Background of the Invention and Technical Problems Posed By the Prior Art

Heat exchangers of interest to the present invention are disclosed in file number DE 103 33 150.6 (filed Jul. 22, 2003 at the DPMA) and DE 102 37 769.3 (filed on Aug. 17, 2002 at the DPMA).

The present invention provides a still further development of this state of the art.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a heat exchanger is provided, including a core, two collecting tanks, and closure caps, all produced from solder-coated aluminum facilitating formation of a metallic bond therebetween via a soldering process. The core includes a plurality of alternating flat tubes and ribs, with the flat tubes on opposite ends extending through openings in spaced tube plates, where each of the tube plates have longitudinal and transverse connection edges forming four corner regions. Each collecting tank has two longitudinal walls joined to the longitudinal connection edges of one of the tube plates. The closure caps close ends of the collecting tanks, and have an edge aligned substantially parallel to the collecting tank walls. The edges of the longitudinal walls of the collecting tanks are arranged between the longitudinal connection edges of the tube plates, with protrusions on the edges of the longitudinal walls inserted in openings in the tube plates. The transverse connection edges of the tube plates have a contour cut-out matching the closure cap profile to form a tight and strong solder bond with the closure caps.

In one form of this aspect of the present invention, at least one fixing member is adapted to secure the closure cap to the collecting tank. In one further form, the fixing member is a bendable bracket on the collecting tank and bendable into a notch cut-out in an edge of the closure cap. In another further form, the fixing member comprises at least one clamp on an edge of the closure cap and adapted to grip over an edge of the collecting tank.

In another form of this aspect of the present invention, the contour cut-outs of the transverse connection edges are provided between the longitudinal connection edges of the tube plates.

In still another form of this aspect of the present invention, the contour cut-outs are formed between two protruding longitudinal connection edges and have a gradation on each side, wherein the gradation size corresponds to the wall thickness of the corresponding collecting tank. In a still further form, the solder bond is formed in each corner region between the protruding longitudinal connection edge, the edge of the closure cap, and one of the longitudinal wall protrusions, wherein the one protrusion is between the edge and the longitudinal connection edge.

In yet another form of this aspect of the present invention, at least one region of the contour cut-out is adapted to be selectively formed like a flange, where the flange provides a surface area for the soldering bond of the tube plate to the closure cap.

DETAILED DESCRIPTION OF THE INVENTION

The figures show a heat exchanger particularly adapted for use in motor vehicles. The heat exchanger includes flat tubes10, corrugated ribs12, and tube plates14. Openings16in the tube plates14hold the ends of flat tubes10, and longitudinal and transverse connection edges20,22form four corner regions.

The heat exchanger also includes collecting tanks26with two longitudinal walls28,30for connection with the longitudinal connection edges20and with side parts or plates34having closure caps36, for closing the side openings of the collecting tanks26, where the closure caps36have a beveled edge40.

Moreover, in the practical example shown, members44are provided to fix the heat exchanger at the edge of the collecting tank26and to the edge40of cooperating closure cap36.

All the parts of the heat exchanger mentioned above may advantageously be made from aluminum sheet which is expediently coated with solder in order to produce a metallic bond using a soldering process. (As used herein, the terms solder and soldering include braze alloy and brazing.)

The longitudinal walls28,30of the collecting tanks26are arranged between the longitudinal connection edges20of the tube plates14. Further, protrusions48are provided on the longitudinal walls28,30and are inserted into the corresponding openings50in the tube plates14.

The longitudinal connection edges22of the tube plates14have a contour cut-out54which forms a tight and strong soldering bond with the closure caps36. The protrusions48may advantageously have a slightly conical form so that a certain guidance is provided into openings50and while at the same time ensuring that the protrusions48lie tightly at the edge of openings50. The protrusions48and the openings50are arranged at appropriate distances so that they can fulfill their function. Since, in the regions around openings50, sufficient soldering material is available, a tight soldered bond of protrusions48in openings50is expected and at the same time a high process safety is provided. The openings50in the tube plate14are preferably arranged between the openings16for the flat tube ends, so that a maximum depth of the tube-rib-block is provided. Furthermore, they are preferably located directly at the longitudinal connection edge20.

The contour cut-out54of the transverse connection edges22is provided between the longitudinal connection edges20. The contour cut-out54corresponds approximately to the contour of closure cap36, so that a strong and tight soldered bond is also achieved therebetween. Thus, the contour of the cut-out depends on the selected contour of closure cap36. As shown especially inFIG. 2, in combinations withFIGS. 9 and 10, the contour cut-out54in the practical example is designed so that the two longitudinal connection edges20protrude somewhat beyond the remaining transverse connection edge22of the tube plate14(the protruding longitudinal connection edges are indicated by reference number58inFIGS. 2,9and10).

Furthermore, the contour cut-out54in the practical example may advantageously include a gradation60on both sides, the size of which corresponds approximately to the plate thickness of the collecting tanks26and to the plate thickness of the longitudinal walls28,30, respectively. The protruding longitudinal connection edges58thus each take up a protrusion48between them and the edge40of closure cap36. In the case of tube plates14which have a somewhat larger plate thickness, the connection between their transverse connection edge20and the closure cap36can be formed without a flange, as shown inFIG. 12. On the other hand,FIGS. 13 and 14show a flange64a, b, where inFIG. 13the flange64ais directed downward and inFIG. 14the flange64bis directed upward in order to create a strong and tight soldered bond even when the tube plates14are thinner.

Cut-outs or notches70may also be advantageously be provided at the edge40of the closure cap36, into which the fixing members44(such as a bracket) on the transverse wall of the collecting tank26may be bent. This member provides a temporary holding of the heat exchanger during the manufacturing phase. The partial longitudinal section shown inFIG. 11goes exactly through the fixing member44and shows the members44(bracket) in the already bent state.

The mounting process of the heat exchanger according to one aspect of the invention is as follows.

The flat tubes10are arranged alternatingly with the corrugated ribs12to the so-called rib-tube-block. Then the side parts34with closure caps36are mounted.

Tube plates14are then mounted on both ends of the flat tubes10, after which the ends of flat tubes10are inserted into the openings16of the tube plates14(only one end is shown in the figures, but it should be appreciated that the same structure may be provided on both ends). Finally, the collecting tanks26are placed onto the tube plates14and the protrusions48are pushed into openings50. Thus, the longitudinal direction of collecting tanks26is established.

At the same time, pressing of the longitudinal connection edges20of tube plate3onto the longitudinal walls28,30of the collecting tanks26is achieved. After that, the fixing members44are bent into the cut-outs70at the edge40of the closure caps36. It should thus be appreciated that at this point the heat exchanger is a self-contained unit, which can be prepared for the soldering process.

It should also be appreciated that a complete heat exchanger is not shown in the figures to avoid unnecessary clutter and to clearly highlight the aspects of the present invention. A person of ordinary skill in the art will readily recognize the suitable additional components and/or features which may be advantageously used with a heat exchanger incorporating one or more aspect of the present invention. For example, a heat exchange medium may enter the collecting tank26through an inlet connector72(seeFIGS. 1 and 2), from which it may be distributed to the flat tubes10in order to flow through the tubes10to an identical or similar collecting tank (not shown) located on the other end of the heat exchanger (in the longitudinal direction of the flat tubes). An outlet connector (not shown) may be arranged either on the collecting tank26shown or on the one not shown, in order to lead the heat exchanger medium away from the heat exchanger.

Cooling air flows through corrugated ribs12which advantageously are in heat-exchanging relationship with the medium mentioned. Furthermore, only one side part34is shown, but it is understood that a second side part is present on the second side which is not shown (in the transverse direction to the flat tubes), which may be identical at least with regard to the characteristics described here.

FIG. 15illustrates an alternative embodiment of the present invention, in which the closure caps36′ are formed as individual parts separate from the core side plates. In this embodiment, contour cut-outs54′ are provided in the transverse connection edges22′ of the tube plates14′. Furthermore, as described with the previous embodiment, protrusions48are present on the edges of the longitudinal walls28,30of collecting tanks26, which are introduced into the corresponding openings50(not seen inFIG. 15) in the tube plates14′. The fixing members44may with this embodiment be particularly advantageously usable, and may consist of clamps74formed on the edges40of the closure cap36.

It should be appreciated that good soldered bonds are advantageously provided with the present invention, with the edges of the longitudinal walls28,30of the collecting tanks26arranged between the longitudinal connection edges20of the tube plates14, where protrusions48are provided on the longitudinal walls28,30which are inserted into the corresponding openings50in the tube plates14, and the transverse connection edges22of the tube plates14are provided with a contour cut-out54so that they form a tight and strong soldering bond with the closure caps36. The protrusions48in the openings50cause the longitudinal walls28,30of the collecting tanks26, when the protrusions48are inserted in the openings50of the tube plate14, to be pressed tightly to the longitudinal connection edges20of the tube plate14. The contour cut-out54in the transverse connection edges22of the tube plates14leads to tight soldering bonds in the corner regions of the tube plates14, and enables the closure caps36to be more easily manufactured without requiring sharp edge corners. The flange-like edge also assists in ensuring secure bonding by increasing the bonding surface area to the closure cap. This may be particularly advantageous for use with tube plates which have a reduced thickness.

Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.