Heat Exchanger, in Particular a Charge Intercooler or Coolant Cooler for Motor Vehicles
The invention relates to a heat exchanger (1), in particular a charge intercooler or coolant cooler for motor vehicles, which comprises a soldered block which is made of pipes (4), ribs and at least one pipe base (2), in addition to at least one plastic box (3) which has a wall (3a) which extends in the cross-section and which is approximately U shaped and a surrounding flange (3b). The box is mechanically connected to the pipe base over flange (3b). According to the disclosure, reinforcing ribs are arranged on the inner side of the plastic box (3) in a transition area between the flange (3b) and the wall (3a).
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The invention relates to a heat exchanger, particularly a charge intercooler or coolant cooler for motor vehicles according to the preamble of claim 1.
Known heat exchangers, particularly for motor vehicles, frequently have a soldered block, consisting of pipes, ribs as well as pipe bases, on which collection boxes made of plastic are attached. The connection between the plastic boxes and the pipe base is designed as a clamp or crimp connection, where a seal is inserted between a flange of the plastic box and the pipe base and clamped by the box/base connection. As a result, the plastic boxes are connected firmly and sealingly to the metallic pipe base.
Such a box/base connection has become known from DE-B 28 52 408 of the applicant, where deformable marginal areas of a pipe base engage via a flange of a water box, and thus establish a positive-lock connection. If the internal pressure is increased, the plastic boxes tend to be exposed to deformations and elevated stresses, particularly above the clamping area, which can also lead to leaks of the box/base connection.
In DE-A 6b 38 41 470 of the applicant, a modified flange area has therefore been proposed for so-called wavy slot crimping, wherein the wall of the box is designed to be wavy above the flange, and thus the longitudinal wall is stiffened.
In charge intercoolers, such as those disclosed in DE-A 198 57 435, higher internal pressures occur particularly inside the plastic box, and the trend is towards increased pressures in future developments, so that conventional plastic boxes are unable to withstand the stress. Rather, deformations can occur, which result in increased stresses and crack formation.
The problem of the invention is to improve a heat exchanger of the type mentioned in the introduction, particularly its plastic box with regard to resistance to internal pressure, without at the same time substantially increasing the weight of the heat exchanger.
This problem is solved by the characteristics of claim 1. According to the invention, a plurality of reinforcing ribs is provided on the interior side of the plastic box above the flange, i.e., in the transitional area between the flange and the box wall. As a result, the advantage is achieved that the plastic box, in case of increased internal pressure, is reinforced in the critical area and becomes more resistant to deformations. Thus, in this area of the box, above the box/base connections, stress peaks are reduced to a permissible value. In particular, a plastic box that has been reinforced according to the invention can be used as a charge intercooler.
In an advantageous embodiment of the invention, the plastic box has a U-shaped cross-sectional profile, which due to an offset becomes the circumferential flange. In the corner area of the offset, which is designed with a substantially obtuse angle, the reinforcing ribs are arranged on the interior side, and their inner edges are preferably aligned with a U profile of the interior wall of the box. As a result, the advantage is achieved that the reinforcing ribs are arranged in an area where they do not pose any noteworthy flow resistance against the medium, that is the coolant or charge air which flows through the box, i.e., the reinforcing ribs according to the invention do not produce an increased pressure drop in the plastic box. They also do not produce a noteworthy weight increase, because the wall thickness of the box itself is not increased, and the ribs are formed with relatively thin walls. Thus, they increase the section modulus in the critical area of the box, in a relatively weight-neutral way and without pressure loss, where the box is stressed particularly due to bending as a consequence of the increased internal pressure at this place.
In an advantageous variant of the invention, the heat exchanger has a block with a single row or multiple row flat pipe system, where the ends of the flat pipes are received in through holes in the pipe base. The reinforcing ribs have a separation from each other, which corresponds to the pipe spacing, i.e., the separation of the pipes, or to an external rib spacing, i.e., the separation of ribs on the external side of the box. Here, the reinforcing ribs can be arranged either at the height of the pipes or between them. The result is an even reinforcement of the longitudinal wall of the box which is adapted to the internal pressure load.
In another advantageous embodiment of the invention, the transitional area between the flange and the box wall has a wavy design in the longitudinal direction of the box, as is already known from DE-A 38 41 470 of the applicant that was mentioned in the introduction. The reinforcing ribs are arranged advantageously in the area of this wave profile, in the area of recesses (wave troughs) or the bulges (wave crests) on the interior side of the box. As a result, the advantage achieved is that of an additional reinforcement without a noteworthy increase in the pressure loss in the box.
In another advantageous embodiment of the invention, the rib surfaces, which protrude into the interior of the plastic box, are arranged parallel to the mold removal direction of the box. Thus, the rib profiles can be incorporated into the core of the box, which is removed, after completion of injection molding of the box, in the demolding direction without the use of additional core slides, i.e., they can be removed from the mold. As a result, the advantage of lower manufacturing costs is achieved since no substantial increase in the cost of the injection tool is associated with the design and arrangement of the reinforcing ribs according to the invention.
An embodiment example of the invention is represented in the drawing and explained in greater detail below. In the drawing
Claims
1-10. (canceled)
11. A heat exchanger, particularly a charge intercooler or coolant cooler for motor vehicles, with a specially soldered block consisting of pipes (4), ribs and at least one pipe base (2), as well as at least one box (3), particularly one made of plastic or metal, which has a wall (3a), particularly one with an approximately U-shaped cross section, and a circumferential flange (3b), and which is connected mechanically via the flange (3b) to the pipe base (2), characterized in that, on the internal side of the box (3), particularly in a transitional area (5), reinforcing ribs (6) are arranged between the flange (3b) and the wall (3a).
12. The heat exchanger according to claim 11, characterized in that the transitional area has an offset (5) which is directed inward and in particular is peripheral.
13. The heat exchanger according to claim 11, characterized in that the reinforcing ribs (6) have inner edges (6a) that are designed to be in alignment with the internal wall (3d).
14. The heat exchanger according to claim 11, characterized in that the pipes are designed as round, oval or flat pipes (4), arranged in one or more rows, and received in the at least one pipe base (2), and in that the reinforcing ribs (6) are arranged on the walls (3a) of the plastic box (3) with separations that correspond to the pipe spacing or to an external rib spacing.
15. The heat exchanger according to claim 14, characterized in that the reinforcing ribs (6) are arranged in each case at the height of the pipes (4).
16. The heat exchanger according to claim 14, characterized in that the reinforcing ribs (6) are arranged in each case between the pipes (4).
17. The heat exchanger according to claim 11, characterized in that a transitional area (9) is included as part of te construction, said transitional area (9) having a wavy design and exhibits recesses (10) as well as bulges (11) on the interior side, and recessed areas on the external side of the plastic box (7, 13) in which parts of the pipe base engage with positive locking.
18. The heat exchanger according to claim 17, characterized in that reinforcement ribs (8) are arranged above the recesses (10).
19. The heat exchanger according to claim 17, characterized in that other reinforcing ribs (12) are arranged in the area of the bulges (11) and between the recesses (10).
20. The heat exchanger according to claim 11, characterized in that the reinforcing ribs (6) have rib surfaces that are arranged parallel to the direction of removal of the box (3) from a mold.
21. The heat exchanger according to claim 17, characterized in that the reinforcement ribs (8) have rib surfaces that are arranged parallel to the direction of removal of the box (7) from a mold.
22. The heat exchanger according to claim 19, characterized in that the other reinforcing ribs (12) have rib surfaces that are arranged parallel to the direction of removal of the box (13) from a mold.
Type: Application
Filed: Jan 12, 2006
Publication Date: Apr 3, 2008
Applicant:
Inventors: Holger Loewe (Ludwigsburg), Frank Von Luetzau (Berglen), Joerg Wilhelm (Victoria)
Application Number: 11/795,459
International Classification: F28F 9/02 (20060101);