CN1771424A - Heat exchanger, especially a charge-air cooler for motor vehicles - Google Patents

Abstract

This invention provides a heat exchanger, particularly a turbocharged air cooler for automobiles, comprising a flat tube with a tube end, a manifold connected to a tube sheet, wherein the tube sheet has an opening for receiving the tube end and has a wide face and a narrow face, and includes a limiting plate and a grooved transition region located between the narrow face and the limiting plate, and the tube end is brazed to the opening. According to the invention, the transition region includes a reinforcing mechanism.

Description

Heat exchangers, especially automotive charge air coolers

technical field

The invention relates to a heat exchanger, in particular to a charge air cooler for a motor vehicle according to the preamble of claim 1 .

Background technique

Known automotive heat exchangers, such as charge air coolers and coolant coolers, are brazed from aluminum (aluminum alloys), where it is either only the heat exchanger core or includes the header tank in the The entire heat exchanger inside. Heat exchanger cores, especially charge air cooler cores, consist of a row of flat tubes with corrugated fins arranged between them. The tube ends of the flat tubes are inserted into openings in the tube plate, so-called flanged holes. This creates a secure, airtight tube/plate connection. The header box is brazed or welded to the tube sheet. In order to connect the collecting box and the tube plate, the tube plate has a continuous limit pressure plate, which overlaps with the collecting box from above or below and forms a brazing surface. The flanging hole on the tube plate runs through the entire depth of the tube plate, that is, from the longitudinal plane to the longitudinal plane. At the same time, there is a transition zone between the narrow face of the flanging hole and the limiting plate, which is in the shape of a U-shaped groove. The tube plate, on the other hand, has an approximately rectangular, optionally continuous groove, which consists of two parallel wide sides and two parallel narrow sides. The longitudinal face of the tube sheet is opposite to the narrow face of the flange hole. In operation, the header tank is subjected to internal pressure from a heat exchange medium such as compressed charge air. During this process, due to the bending stress, stress concentrations occur on the narrow side of the flange hole, so that the transition zone between the longitudinal side of the tube plate and the narrow side of the flange hole deforms. Especially the narrow faces of the tube/plate connections and the tube corners are stressed by this stress and deformation, so that leaks can occur in the heat exchanger.

Contents of the invention

The object of the present invention is to improve the tube-sheet connection on the aforementioned heat exchangers and to avoid undesired stresses.

This object is achieved by the features of claim 1 . According to the invention, the transition zone on the tube sheet is reinforced. The advantage of this approach is that it avoids unacceptable deformation or bending in the transition zone of the tube sheet and reduces stress concentrations thereby mitigating hazards. Since the tube plate is produced from one slab, the remaining part of it has approximately the same wall thickness, that is to say, in the area of the narrow face of the tube, the deformation of the longitudinal faces of the plate is small. This results in less or almost no bending of the tube/plate connection, but only displacement, which is clearly more favorable for stressing.

The reinforcement of the transition zone can be achieved through several design solutions, which are the preferred embodiments described in the dependent claims. Reinforcement can be done, for example, by making the material thicker, which will increase the flexural stiffness of the transition zone. In terms of manufacturing, it can be strengthened by upsetting the material. Another advantageous form of reinforcement is the reinforcement of the tube sheet in the transition zone by means of one or more grooves. In this way, under the condition that the wall thickness of the tube sheet remains unchanged, the deformation resistance can be increased by improving the stability. The recess is preferably arranged in the narrow area of the flange opening, so that the bending stiffness is increased there.

According to a further preferred embodiment of the invention, the reinforcement is formed by a profiled strip, which fills the groove-shaped transition region and is brazed to the tube plate. Reinforcement can also be achieved with profiled strips, ie an additional part is connected to the tube sheet to form a bending zone. In this way, a connection, ie a fixed connecting bridge, is formed between the outer clamping plate on the tube plate and the narrow side of the flange hole, which prevents bending or deformation of the transition region. This prevents damaging bending stresses in the tube/plate connection.

According to an advantageous further development of the invention, the profile strip is integral with the collecting tank, that is to say it forms the downward extension of the longitudinal sides of the collecting tank, ie in the direction of the tube plate. This does not increase the manufacturing or installation costs, since the collecting tanks are still placed on the tube sheet and brazed to it as before.

According to a further embodiment of the invention, the profile strip is a (separate) insert strip, ie it is inserted as an additional part into the groove-shaped transition region and is brazed to the tube plate. The advantage of this form is that neither the tube sheet nor the collecting box needs to be changed. Such insert plates can be used in heat exchangers such as charge air coolers for higher pressure charge air. Thus, this cooler can be adapted to higher operating pressures by means of this simple, targeted measure.

In a further preferred embodiment of the invention, on the inner side facing the tube sheet, the profile strip or the insert strip has a recess in the narrow area of the tube, which partially clamps the flange hole, that is to say, it Fits snugly on its narrow faces and corner areas and supports them. This prevents damaging stress concentrations in the corner regions of the tube.

Description of drawings

The invention is described in detail below by accompanying drawings and embodiments, wherein,

Figure 1 is a partial view of a charge air cooler,

Figure 2 is a view of the charge air cooler shown in Figure 1 with the embedded slats shown hatched,

Figure 3 is a sectional view of the charge air cooler shown in Figures 1 and 2,

Figure 4 is a view of the tube sheet, where the embedded slats are indicated by hatching,

Figure 4a is a cross-sectional view of the tube sheet,

Fig. 5 is another embodiment of the invention, with one-piece profiled slats.

Detailed ways

Figure 1 is a partial view of the charge air cooler showing the charge air box and the tube/plate connections. Such charge air coolers are used for cooling the compressed air of motor vehicles, in particular trucks. The collecting tank 1 (also referred to as charge air tank) is U-shaped in cross-section and is preferably made of an aluminum alloy. Overall, the collecting tank 1 has a slightly elongated tank body, which can be formed by deep drawing or casting. The U-shaped profile of the collecting tank 1 has two arms 2 , 3 which form the longitudinal sides of the charge air tank. The collecting tank 1 is inserted into the tube base 4 and has stop plates 5 , 6 on the longitudinal sides which are approximately perpendicular to the bottom plate 7 . The bottom plate 7 is provided with numerous flanged holes, of which only the flanged hole 8 is shown, and the pipe end 9a of the flat tube 9 is inserted into this hole. The overall heat exchanger or intercooler has a multitude of flat tubes, between which corrugated fins (not shown) are arranged, which form secondary heat exchange surfaces for the ambient air. The two arms 2, 3 of the box profile have connecting sections 2a, 3a on the lower part, that is, on the open side, which overlap the limiting pressure plates 5, 6 of the tube plate 4 and are brazed there. Insert strips 10 , 11 are arranged below the bottom sides of the connection sections 2 a , 3 a , which are indicated by hatching.

FIG. 2 shows a cross-sectional view of the collecting tank 1 shown in FIG. 1 in front of the flange opening 8 . As in the prior art, the tube plate 4 is produced from a blank, so that its wall thickness s remains substantially unchanged. The direction of the flanging of the flanging hole 8 is inward, that is, towards the collecting tank 1 . The pipe end 9a of the pipe 9 passes through the burring hole 8 and protrudes inwardly. In another embodiment not shown in the figure, the flange hole is flanged outward. In this case, the tube ends can protrude beyond the surface of the tube sheet or, preferably, be below this surface of the tube sheet.

The flat bottom plate 7 becomes a groove shape at the longitudinal surface of the tube plate 4 outside the flange hole 8 and inside the limiting pressure plates 5 and 6. Here, this groove transitions to the bottom plate 7 on the one hand, and the other On the one hand, it transitions to the position-limiting pressing plates 5,6 again, that is, the transition zones 12,13 are formed. This transition zone 12 , 13 forms a longitudinal groove to increase the stability of the tube sheet 4 . As the collecting tank 1 is subjected to the internal pressure caused by the compressed air, compressive and/or tensile forces appear on the longitudinal faces 2, 3 of the collecting tank 1, and these forces are transmitted to the limiting strips 5, 6 of the tube sheet , so that the transition zone 12, 13 produces bending stress and leads to deformation. The invention then provides for insert strips 10 , 11 which, as profiled plates, have a shape that corresponds to the contour of the transition regions 12 , 13 . In this way, the outer sides of the embedded slats 10, 11 are attached to the position-limiting pressure plates 5, 6, the lower side is located above the groove-shaped transition areas 12, 13, and the inner side is attached to the narrow surface of the flanging hole 8. Gaps 14 , 15 are provided above the insert strips 10 , 11 . As already mentioned, the insert strips 10 , 11 are preferably made of an aluminum alloy and are brazed to the tube plate 4 , that is to say to the entire heat exchanger in one work step.

Fig. 3 is a sectional view on a plane parallel to the drawing plane of Fig. 2 . The outline of the flanged hole 8 can be clearly seen in the figure: the flanged hole 8 forms an acute angle with the outer wall of the pipe 9, and this angle is filled by the crescent-shaped solder 16 after brazing. Above the meniscus-shaped solder is the tube at the flange hole 8, which has a relatively narrow gap here. As mentioned above, the transition zone 12, 13 is formed by the flanging hole 8 and the two outer limiting pressure plates 5, 6 of the tube plate, whose cross-section is an asymmetrical U-shape, and is embedded in the slats 10, 11 fill up. Between the limiting platen 5,6 and the flange hole 8, precisely between the narrow face of the flange hole, the embedded slats 10,11 form a fixed connection bridge, which plays a role in preventing the deformation of the transition zone 12,13 role. In this way, the stress concentrations that occur in the prior art are reduced and the loads on the tube/plate connection in the region of the narrow area are significantly reduced. In this way, the charge air box 1 can withstand a higher pressure.

Fig. 4 is a sectional view along the line IV-IV shown in Fig. 4a. Corresponding to the shape of the tube 9 (not shown), the flange hole 8 has an approximately rectangular inner and outer cross-section, the wide and narrow sides of which are respectively 8a and 8b. The insert strips 10 , 11 rest against the narrow face 8 b of each flange hole, ie they have recesses 10 a , 11 a of the same shape as the narrow face 8 b in the region of the narrow face 8 b. Together with the soldering, this tight fit of the insert strips 10, 11 produces a very good support effect, ie a bending-resistant connection, for the opposing tube plate parts. The recesses 10a, 11a can be formed by die casting (Prögen).

Figure 4a is a cross-sectional view of a tube sheet 4 with a flanging hole 8, the outside of the flanging hole is a conical zone 8c, and its inside is a cylindrical zone 8d (this matches the cross-section of the flat tube 9) . The tapered region 8c serves as an introduction bevel for the tube end 9a. The flange hole 8 is formed by punching-punching-die-casting on the tube base 7 (see FIG. 2 ).

Another embodiment of the invention is shown in FIG. 5 , where the above-mentioned insert strips are integrated with the charge air box, ie integrally formed. The tube sheet 4 remains unchanged; the collecting box 17 has connecting regions 17a, 17b, the bottom edges of which form profile strips 18, 19, which fill the groove-shaped transition regions 12, 13 on the tube sheet 4. In principle, this embodiment has the same effect as described above, namely the reinforcement of the transition regions 12 , 13 . As long as the collecting tank 17 is cast or die-cast, the rounded bases 18 , 19 can be produced directly by the corresponding shape of the casting mold. In the construction of the charge air box 17 with the profiled base 18 , 19 , it is no longer necessary to insert the previously described insert strips, ie a working step can be omitted. It is also possible to fix the special-shaped slats on the bottom edge of the charge air box in a similar manner such as pasting.

Other methods of strengthening the transition zone, not shown in the figure, include reinforcement by grooves, that is to say, the bending coefficient of the section is increased by corresponding shaping, and thus the bending stiffness is increased. Grooves can be formed simultaneously in the narrow area of the flanging hole when making the tube sheet. In addition, the wall thickness of the transition zone can also be increased by upsetting the tube sheet in the transition zone. This method also has the effect of reducing destructive stress concentrations in the area of the tube/plate connection, ie in the area of the narrow faces and tube corners.

reference number

1 Charge air box 2 Longitudinal side

2a Connection area 3 Longitudinal plane

3a Connection area 4 Tube plate

5 Limiting plate 6 Limiting plate

7 Bottom plate 8 Flanged hole

8a wide noodles 8b narrow noodles

8c Conical zone 8d Cylindrical zone

9 flat tube 9a tube end

10 Embedded slats 11 Embedded slats

12 Transition zone 13 Transition zone

14 Clearance 15 Clearance

16 crescent-shaped solder 17 collecting box

17a Connection Area 17b Connection Area

18 One-piece special-shaped slats 19 One-piece special-shaped slats

Claims (8)

1. heat exchanger, charger-air cooler especially for automobile, have flat tube (9), comprise brazing filler metal with tube sheet (4) and the manifold (1) that is connected with pipe end (9a), wherein, tube sheet (4) has and is used to admit pipe end (9a) and has wide (8a) and the opening (8) of leptoprosopy (8b), also have spacing pressing plate (5,6) and be positioned at leptoprosopy (8b) and spacing pressing plate (5,6) between groove shape transition region (12,13), and pipe end (9a) and opening (8) brazing filler metal, it is characterized in that this transition region (12,13) has reinforcing mechanisms.

2. heat exchanger according to claim 1 is characterized in that, this reinforcing mechanisms constitutes by the material thickening.

3. heat exchanger according to claim 1 is characterized in that, this reinforcing mechanisms comprises that by employing the reinforcing of groove constitutes.

4. heat exchanger according to claim 1 is characterized in that, this reinforcing mechanisms constitutes by special-shaped lath, this abnormal shape lath transition region (12,13) is filled up at least in part and with tube sheet (4) brazing filler metal.

5. heat exchanger according to claim 4 is characterized in that, this abnormal shape lath (18,19) becomes one with manifold (17).

6. heat exchanger according to claim 4 is characterized in that, this abnormal shape lath is for embedding lath (11,12).

7. according to claim 4,5 or 6 described heat exchangers, it is characterized in that described opening is direction flange hole (8) inwardly, and special-shaped lath (10,11) has recess (10a, 10b), they match with the leptoprosopy shape of flange hole (8).

8. according to the described heat exchanger of one of aforementioned claim, it is characterized in that this opening is direction flange hole outwardly.

Images