EP1953490B1 - Header and heat exchanger with such a header - Google Patents

Description

The invention relates to a collecting box according to the preamble of claim 1 and a heat exchanger according to the preamble of claim 3 - each known by the EP 1 515 109 A2 ,

By the DE 10 2005 031 475 A1 Furthermore, a collecting tank for a heat exchanger and a heat exchanger with two such collection boxes was known, in particular for use as a coolant radiator for a motor vehicle. The known heat exchanger is designed as a Ganzaluminiumwärmeübertrager and preferably completely, that is soldered in one operation. The known heat exchanger essentially has a tube-and-fin block, which consists of flat tubes and corrugated ribs arranged between them, and two collecting boxes, with the ends of the flat tubes each opening into the collecting boxes. The known heat exchanger is the primary side flows through by a heat transfer fluid, in particular a coolant of a cooling circuit for an internal combustion engine and the secondary side of ambient air. The headers of the known heat exchanger are formed substantially in two parts, ie they have a bottom part, consisting of a bottom and at least two adjoining, parallel side walls, and a cover part. Bottom part and lid part and additional end walls form a closed box. In the bottom extending slots are arranged transversely to the longitudinal direction for receiving the flat tube ends. The Slits extend in their longitudinal direction substantially over the full width of the floor, ie they extend from one side wall to the other side wall.

The known heat exchanger may also have additional partitions in the headers and thus as a multi-circuit heat exchanger, z. B. can be used as a coolant radiator with a first part cooler for a high-temperature circuit and a second part cooler for a low-temperature circuit. During operation of such a coolant radiator, as a result of different temperatures in the individual tubes of the tube-and-fin block, considerable stresses, caused by different expansions, can occur. In particular, in the area of the partitions such mechanical stresses are greatest, with the result that in particular the pipe / floor connections are heavily loaded in this area, especially at changing temperatures and stresses. The pipe / floor connections are particularly the most stressed on their narrow sides, which has its cause in additional bending stresses, which are superimposed on the tensile or compressive stresses. The bottom of the bottom part facing the narrow sides of the tubes in the depth direction, d. H. in the air flow direction on a supernatant, which acts as a lever arm and causes a proportion of the complex three-dimensional bending stress.

Proposed solutions are known in order to reduce the mechanical stresses of a heat exchanger, in particular in the area of the pipe / floor connections. By the DE 103 43 239 A1 was a heat exchanger with a passages having tubesheet known. The elongated passages for receiving flat tubes extend substantially over the entire width of the tube plate and are stiffened by circumferential, funnel-shaped flanks. A disadvantage of the known heat exchanger is also here that between the narrow sides of the passages and the longitudinal edge of the tube plate, a projection exists, which forms a lever arm at thermo-mechanical internal pressure stress of the header box and thus bending stresses causes the narrow or end faces of the pipe / floor connection. In particular, this causes an elongation of the components.

The mentioned problem of bending stresses was solved by a solution according to DE 103 16 756 A1 thereby taken into account that between the narrow side of the pipe / floor connection and the edge of the tube sheet a Einlegeleiste is arranged, which acts as a stiffening of the soil in the critical region and thus reduces the multi-dimensional stresses. The disadvantage here is the additional weight and the remaining supernatant of the tube plate against the flat tubes in the depth direction, which brings an increased depth.

Another design for heat exchangers is known by so-called flat-tube condensers for motor vehicles, being used as a collecting container for the pipes to be distributed to the refrigerant headers, which have a substantially circular cross-section due to the relatively high internal pressure stress. The manifolds may be formed in one or two parts, ie with a bottom part, in which slot-shaped passages are arranged, and a lid part which is soldered to the bottom part. By the DE 41 30 517 A1 a flat tube condenser with a manifold was known, which is constructed in two parts, ie, a bottom part and a cover part. The arranged in the arched bottom part passages extend over the entire clear width of the bottom part and take the flat tube ends in itself. The entire flat tube capacitor is usually soldered in one operation.

By the EP 714 008 A2 a heat exchanger in the form of a flat tube condenser with a one-piece collecting tube has been known which has a closed, substantially circular cross-section. The manifold has transverse to the longitudinal direction extending slots which receive the ends of flat tubes of a tube-rib block in it. The slots have - according to embodiments of FIG. 6 to 10 - a slot length (corresponding to the depth of a flat tube), which is greater than the inner diameter of the manifold. This is done by a achieved partial radial expansion of the walls of the manifold in the form of grooves or pockets, in which the end faces of the flat tubes come to rest. The slot grooves each have a shoulder which serves as a stop for the insertion depth of the flat tubes.

It is an object of the present invention to design a collecting box and a heat exchanger of the type mentioned in such a way that the mechanical stresses on the components such as pipes and tubesheet and the pipe / floor connections are reduced.

This object is first achieved by the features of claim 1, wherein it is provided that the slot length, d. H. is extended from narrow side to narrow side so that the narrow sides of the openings (passages) and the flat tubes are in the range of wall thickness of the side walls of the bottom part. The extensions of the front and rear edges of the flat tubes thus fall in the area between the inner surface and the outer surface of the side walls. Thus, the advantage is achieved that with an introduction of forces from the tubes, especially in the area of their narrow sides, a lever arm is omitted in the headers and thus harmful bending stresses are avoided. The forces introduced from the pipe onto the collecting box or from the collecting box onto the pipe have a resultant which lies in the seam of the pipe / floor connection in the narrow side area and in the area of the wall thickness of the side walls. This only shear stresses are transmitted, which are less harmful and lower stress on the heat exchanger. Consequently, the heat exchanger can be dimensioned with smaller wall thicknesses and thus easier to build.

In the side walls of the collecting tank, ie the bottom part, in the region of the slot-shaped openings, convex, local forms are provided which form pockets or grooves for receiving the narrow sides of the flat tube ends of the heat exchanger. The flat tubes solder in the region of their narrow sides or end faces with the inner surfaces of the pockets. In the area of the solder seam, the shear forces resulting from thermal expansion are applied to the bottom part or transfer its side walls. The pockets have a depth t (in the longitudinal direction of the openings) which is less than the wall thickness s of the side walls.

It is further provided that the inner contour of the pockets of the outer contour of the flat tubes in the narrow side region corresponds: when rounding the flat tubes in the end region, the pockets can thus have a semicircular inner contour or a halbkreiszylindrische surface. In a more rectangular shaped narrow side, a corresponding cross section for the pockets must be provided, so that there is sufficient contact surface for soldering and thus power transmission.

The slot-shaped openings are formed in the floor as passages, so that an enlarged contact surface between the floor and pipe circumference, d. H. an enlarged soldering surface for receiving the flat tube ends results. This on the one hand, a stiffening of the soil and on the other hand, an improved absorption of the pipe ends is achieved. The bottom of the bottom part is preferably - for reasons of stability - arched, but may also be formed substantially flat. The production of the passages takes place with tools known from the prior art, for. As punches that allow a hole punching, collar pulling and expanding or stamping pockets in the side walls.

The object of the invention is also solved by the features of claim 3, d. H. by a heat exchanger with at least one collecting box, which has the features of the preceding claims.

Preferably, the heat exchanger is designed as a coolant radiator for a cooling circuit of an internal combustion engine of a motor vehicle. Furthermore, the heat exchanger can be used as a charge air cooler for cooling compressed charge air for an internal combustion engine of a motor vehicle.

In particular, for applications in motor vehicles, the heat exchanger according to the invention is designed as a Ganzaluminiumwärmeübertrager, which is preferably completely solderable and / or weldable. Such heat exchangers are "sorted" and therefore fully recyclable.

Fig. 1

einen Ausschnitt eines erfindungsgemäßen Kühlmittelkühlers in perspektivischer Darstellung,

Fig. 2

einen Ausschnitt eines Bodenteiles des Kühlmittelkühlers gemäß Fig. 1,

Fig. 3

einen Teilschnitt durch das Bodenteil mit erfindungsgemäßen Ausprägungen und

Fig. 4

eine Einzelheit einer Rohr/Boden-Verbindung im Bereich der erfindungsgemäßen Ausprägung.

An embodiment of the invention is illustrated in the drawing and will be described in more detail below. Show it

Fig. 1

a section of a coolant radiator according to the invention in a perspective view,

Fig. 2

a section of a bottom part of the coolant radiator according to Fig. 1 .

Fig. 3

a partial section through the bottom part with features of the invention and

Fig. 4

a detail of a pipe / floor connection in the range of the inventive expression.

Fig. 1 shows a section of a designed as a coolant radiator 1 heat exchanger, which is used in a coolant circuit, not shown, for an internal combustion engine of a motor vehicle. The coolant radiator 1 is - as shown in the drawing - installed in the motor vehicle, ie as a cross-flow cooler, which has only partially shown tube-rib block 2 and two manifolds, of which only a bottom part 3 is shown. The cover part, not shown, serves the closure of the bottom part 3 and corresponds to the aforementioned DE 10 2005 031 475 A1 the entire disclosure of which is included in the present application. The tube-fin block 2 has a plurality of flat tubes 4, between which corrugated fins 5 are arranged. The bottom part 3 consists of a bottom 3a, which tube ends 4a of the flat tubes 4 receives, and two integrally connected to the bottom 3a, arranged in parallel side walls 3b, 3c. On the outer surface of the side wall 3c in the region of the flat tubes manifestations 7 can be seen, which will be explained in more detail below.

Fig. 2 shows the bottom part 3 in a perspective view with a view of the convex bottom 3a, which has transversely extending, slot-shaped openings 6 in the form of passages with narrow sides 6a and long sides 6b. The passages 6 are in their longitudinal direction, ie extended with their narrow sides 6a over the inside width between the two side walls 3b, 3c out by in the side walls 3b, 3c outwardly curved shapes or pockets 7 are formed. The slots 6 have in their central region opposite, inwardly directed lugs 8, which engage in a bead of a not shown Sick tube (flat tube with a central, extending in the longitudinal direction bead).

Fig. 3 shows a longitudinal section through the bottom part in the middle region of the bottom 3a, so that the lugs 8 appear in a cut Darrstellung. The inner surfaces 7a of the pronounced pockets 7 can be seen with a view of the side wall 3c located behind the plane of the drawing. The shape and contour of the inner surfaces 7a corresponds to the outer contour of the flat tubes, which are not shown here, and which are inserted into the passages 6.

Fig. 4 shows a detail of a pipe / floor connection between a flat tube end 4a and a passage 6 in the region of its narrow side, which has the pocket-shaped characteristic 7 according to the invention. The side wall 3c has a wall thickness s, opposite which the pocket 7 is offset outwards. The inner surface 7a of the pocket 7 is offset outwardly from the inner surface of the side wall 3c by the depth t, where t <s. The flat tube 4 or its tube end 4a have a common front edge (trailing edge) 4b whose extension lies within the wall thickness s of the side wall 3c. The extension of the front edge 4b represents a resultant R shown in dashed lines with the introduction of forces from the pipe 4 on the side wall 3c or vice versa. From the graphic representation can be seen that at this force (over the resultant R) in the narrow side of the pipe / Ground connection no lever arm is present, which could cause a bending stress in terms of the pipe / floor connection. Rather, the forces transmitted in the longitudinal direction of the tube 4 in the area of the solder seam (corresponding to the inner surface 7a) are transmitted only by shear stresses. This has one Reduction of the mechanical stress of the pipe / floor connection result. As an additional advantage results - in view of the above-mentioned prior art - a reduction in the depth due to omission of a bottom projection, which is practically shrunk to the wall thickness s of the side walls.

The partial forms 7 of the side walls 3b, 3c can in principle with conventional tools, eg. B. a stamp, as known from the aforementioned prior art, are produced. Thus, in principle no special additional tools for the production of the pockets 7 are required.

The coolant radiator is made entirely of aluminum parts, so it is designed as a so-called Ganzaluminiumkühler and therefore completely, d. H. be soldered in one operation.

The heat exchanger according to the invention with pronounced pockets 7 can also be designed as a charge air cooler, d. H. used for the cooling of compressed charge air for internal combustion engines of motor vehicles. In general, the pipes carrying the charge air have an approximately rectangular cross-section, d. H. with a long and a narrow side, wherein the inner contour of the pockets 7 is to be adapted accordingly to the contour of the charge air pipes.

Claims (6)

1. A collecting box for a heat exchanger (1) having flat tubes (4), with a bottom part (3) having a bottom (3a) and two side walls (3b, 3c) and in particular one or two front walls, wherein the bottom (3a) has slit-shaped openings (6) extending between the side walls (3b, 3c) for receiving ends (4a) of the flat tubes (4) and wherein the openings (6) have-analogous to the cross-section of the ends (4a) of the flat tubes - narrow sides (6a) and longitudinal sides (6b), wherein the narrow sides (6a) are arranged in the region of the wall thickness (s) of the side walls (3b, 3c), wherein the side walls (3b, 3c) partially have pockets (7) with a depth (t) in the region of the narrow sides (6a) of the openings (6), wherein t<s and the pockets are formed as shapes (7) of the side walls (3b, 3c) and the shapes (7) have an inner contour (7a) which is adapted to the outer contour of the ends (4a) of the flat tubes in the region of their narrow sides (4b), wherein the openings are formed in the form of rim holes with narrow sides and longitudinal sides, wherein the rim holes have opposite, inwardly-directed noses (8) in their middle region which, when used, engage with a beading of a flat tube with a middle beading running in the longitudinal direction.
2. The collecting box according to claim 1, characterised in that the bottom (3a) is curved outwards.
3. A heat exchanger having a tube-fin block (2) and at least one collecting box, characterised in that the collecting box is formed according to at least one of the preceding claims.
4. The heat exchanger according to claim 3, characterised in that it is formed and/or can be used as coolant cooler (1) or charge air cooler of a motor vehicle.
5. The heat exchanger according to claim 3 or 4, characterised in that it is formed as all-metal, in particular all-aluminium heat exchanger (1).
6. The heat exchanger according to claim 5, characterised in that it can be completely soldered and/or welded.

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