Abstract:
A heat exchanger having tubes and at least one collecting tube is used, especially for air conditioning units of motor vehicles. The heat exchanger has pipes, at least one manifold that communicates with the pipes, and at least one connection flange. The connection flange is connected in a communicating manner to the manifold via a nozzle and can be connected to a conduit.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a heat exchanger, in particular a condenser for an air conditioning system of a motor vehicle. 
   Condensers for air conditioning systems, as are disclosed for example by EP-A 915 308, have a coolant flowing through them, said coolant entering the condenser via a coolant connecting flange and leaving the condenser again via a further coolant flange. The connecting flanges have a continuous coolant duct which is connected, on the one hand, to a collecting tube of the condenser and, on the other hand, to a coolant inlet line or coolant outlet line. The entire condenser, composed essentially of a tube/rib block, the collecting tubes and the connecting flanges, is soldered in one operation in a soldering oven. For this purpose, it is necessary for the connecting flanges for the soldering process to be secured to the collecting tubes. Hitherto this was done by means of additional parts or soldering devices which has delayed the fabrication process. 
   A two-part connecting flange for attaching a coolant line to a condenser has been disclosed by U.S. Pat. No. 5,163,716. The condenser has a collecting box with a planar connecting face onto which a cuboid connecting block is fitted and is soldered to the collecting box. A coolant line is welded to an adaptor piece which is screwed to the connecting block. The coolant connection from the coolant line is made via the adaptor and a coolant duct in the connecting block. This coolant connection has a plurality of parts and mounting steps and is therefore associated with relatively high manufacturing costs. 
   EP-A 1 167 897 has disclosed a soldered flat tube condenser with two collecting tubes and one collector which is arranged parallel to one of the collecting tubes and is connected on the coolant side to this collecting tube by means of a connecting block with two connecting ducts. Coolant flows out of the condenser into the collector and back again into the condenser from the collector via this connecting block which is soldered to the collecting tube of the condenser. The connecting block has connectors, which are each extensions of the coolant connecting ducts and are inserted into openings in the collecting tube and secured thereto by tack welding or interference fitting. The parts are then soldered. Subsequent to the soldering process, the collecting container is screwed to the connecting block and sealed with respect to it. The collecting container is additionally connected in its upper region to the collecting tube by means of a clamp. The connecting block is thus a connecting and attachment part between the collecting tube and collecting container. The coolant lines are connected, in a way which is not illustrated, to the collecting tubes via an inlet flange and an outlet flange. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to improve the heat exchanger mentioned at the beginning to the effect that a connecting flange is constructed from a small number of individual components and can be secured easily with respect to the collecting tube for the soldering process and can, if appropriate, be soldered to the heat exchanger in one operation. 
   The invention provides for the connecting flange to be secured in a positively locking fashion with respect to the collecting tube by means of a connector, i.e. the connecting flange does not require any other components for securing purposes before the soldering process. The entire heat exchanger can thus be soldered to the connecting flange in a soldering oven. 
   According to one advantageous refinement of the invention, the connector is arranged on the collecting tube and is preferably formed from the collecting tube. It is advantageous if the collecting tube is of two-part construction, i.e. is composed of a bottom and a lid from which the connector can easily be formed, in a similar way to a passage. A corresponding receiving opening, which is also adapted to the round shape of the lid, is provided in the coolant connecting flange—said receiving opening receiving the connector in a positively locking and also frictionally locking fashion so that the two parts are secured. 
   According to a further, particularly advantageous refinement of the invention, the connector is arranged on the connecting flange and is preferably constructed in one piece with the connecting flange. The connecting flange can thus easily be placed on the collecting tube, which may either be of single-part or two-part construction, and inserted into a corresponding opening and this is sufficient to secure the connecting flange. In one advantageous refinement, the connector projects into the interior of the collecting tube and forms an excess length there which can be widened with respect to the opening in the collector tube. This improves the securing effect. Therefore, basically only two parts are necessary to secure the connecting flange and collecting tube, i.e. there is no need for any further securing means or parts. This simplifies the manufacturing and mounting process. 
   In one advantageous refinement of the invention, a further support face is also provided on the connecting flange, specifically at a distance from the connector. The support face is adapted to the rounded shape of the collecting tube or its lid and therefore fits snuggly against its surface. As a result, improved support of the connecting flange with respect to the collecting tube is obtained, specifically both before the soldering process and after the soldering process because the flange is soldered to the collecting tube in the region of this second bearing face. 
   In a further refinement of the invention, a blind hole bore is provided in the connecting flange and said blind hole bore can receive, for example, a holding element for attaching additional parts or a bearing pin for supporting the heat exchanger. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are illustrated in the drawings and will be described in more detail below. In the drawings: 
       FIG. 1  shows a condenser with a coolant connecting flange, 
       FIG. 2  shows a collecting tube of the condenser with a coolant connecting flange, 
       FIG. 3  shows the collecting tube of the condenser without a coolant connecting flange, 
       FIG. 4  shows a lid of the collecting tube, 
       FIG. 5  shows a further view of the collecting tube with a coolant connecting flange, 
       FIG. 6  shows a section along the line VI-VI in  FIG. 5  through the coolant connecting flange, 
       FIG. 7  shows a second embodiment of a coolant flange, 
       FIG. 8  shows a section along the line VIII-VIII in  FIG. 7  through the coolant connecting flange, 
       FIG. 9  shows a view of the coolant connecting flange from below, and 
       FIG. 10  shows a view of the coolant connecting flange from the side. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  shows a coolant condenser  1  which is composed of a tube/rib block  2  and laterally arranged collecting tubes  3 ,  4 . The tube/rib block  2  is constructed from flat tubes (not illustrated in more detail) and corrugated ribs arranged between them. The ends of the flat tubes are received in passages of the collecting tubes  3 ,  4 . The entire condenser  1 , composed of flat tubes, corrugated ribs and collecting tubes  3 ,  4 , is soldered in a soldering oven. A coolant connecting flange  5  is attached to the collecting tube  4  and a coolant line (not illustrated) can be connected to said coolant connecting flange  5 . A further connecting flange for a second coolant line is not illustrated here. 
     FIG. 2  shows the collecting tube  4  with the coolant connecting flange  5  in a somewhat enlarged representation. The connecting flange  5  is, on the one hand, connected (soldered) to the collecting tube  4  in a firm and sealed fashion and has an opening  6  for the connection of a coolant inlet line or coolant outlet line (not illustrated). 
     FIG. 3  shows the collecting tube  4  which is of two-part construction and is composed of a shell-shaped bottom  7  and a shell-shaped lid  8 . The bottom has a series of passages  9  in which the abovementioned tubes are inserted. 
     FIG. 4  shows the lid  8  as an individual part, said lid  8  having a connector  10  in a central region. The coolant connecting flange  5  is secured to the lid  8  by means of this connector  10 , and this is explained below. 
     FIG. 5  shows a further view of the collecting tube  4 , i.e. a side view. The coolant connecting flange  5  is connected only to the lid  8  and has a planar connecting face  11  in which the coolant connecting opening  6  is arranged. 
     FIG. 6  shows a section through the collecting tube  4  and the coolant connecting flange  5  along the section line VI-VI in  FIG. 5 . The coolant connecting flange  5  has an angled coolant duct  12  which communicates, on the one hand, with the collecting tube  4  and, on the other hand, with the connecting opening  6 . The connector  10  is formed from the lid (half shell)  8 , i.e. the connector  10  is constructed in one piece with the lid  8 . Since the lid forms an individual part of the collecting tube  4 , the connector  10  can easily be manufactured by punching a passage, preferably with a circular cross section. The coolant connecting flange  5  has a connecting end  13  on the collecting tube side, which connecting end  13  is, on the one hand, adapted to the contour of the lid  8  and, on the other hand, has a receiving bore  13   a  of the size and shape of the connector  10 . The internal diameter of the receiving bore  13   a  and the external diameter of the connector  10  are matched to one another in such a way that a slight clamping fit is produced. The coolant connecting flange  5  is thus secured to the collecting tube  4  after said coolant connecting flange  5  has been fitted onto the connector  10  and can thus be placed with the entire condenser  1 —without further resources or clamping means—in a soldering oven for the soldering process. After the soldering process, the end  13  of the connecting flange  5  is soldered to the connector  10  or to the lid  8  in a sealed and firm fashion. The connector  5  is thus also able to absorb forces which result from the attachment of a coolant line (not illustrated). From the description above it becomes clear that the coolant connecting flange  5  and the collecting tube  4  have been connected to one another in a fashion which is sealed with respect to coolant, without further parts in the form of connecting means. 
     FIG. 7  shows a further exemplary embodiment of the invention, specifically a coolant connecting flange  14  in a view from above with a coolant connecting opening  15  and a blind hole bore  16 . 
     FIG. 8  shows a section along the line VIII-VIII in  FIG. 7 . The coolant connecting flange  14  is manufactured from an aluminum block and has a continuous coolant duct  17  which ends in the connecting opening  15  at one end and in a connector  18  at the other. The connector  18  of the coolant connecting flange  14  is inserted into a corresponding receiving opening in a collecting tube  19  (illustrated by dashed lines). The coolant connecting flange  14  rests here with a collar  20 , adjoining the connector  18  via a shoulder, on the collecting tube  19 . The connecting flange  14  has, in addition to the collar  20 , a further support face  21  which is adapted to the contour of the collecting tube  19 . These two support faces, the collar  20  and the second support face  21 , mean that the connecting flange  14  is supported doubly with respect to the collecting tube  19 . The length of the connector  18  is dimensioned such that it projects into the collecting tube  19  and forms an excess length ü with the inner wall. The connector  18  can be widened conically (not illustrated) in the region of the excess length ü as a result of which better anchoring and securing of the connecting flange  14  with respect to the collecting tube  19  is achieved. The blind hole bore  16  is used to receive a pin-shaped holding element (not illustrated) to which additional parts can be attached. 
     FIG. 9  shows a view of the connecting flange  14  from below, i.e. in the direction of the coolant duct  17  and with a view of the circular support face of the collar  20  and the end face of the connector  18 . Furthermore, the arched support face  21  which is stepped with a radius R can be seen. 
     FIG. 10  shows the coolant connecting flange  14  from the side, it being possible to see an arcuate contour  21   a  of the support face  21 : said contour  21   a  is designed to correspond to the contour of the collecting tube  19  so that closely fitting abutment between the collecting tube  19  and the support face  21  is produced in this region. 
   From the above description, it is in turn clear that the coolant connection  14  and the collecting tube  19  are connected to one another without further additional parts, with the connector  18  assuming the securing function. The seal-forming soldering process takes place between the external circumference of the connector  18  and the corresponding receiving opening in the collecting tube  19 . The soldering process is preferably carried out in accordance with the Nocolok method. 
   The invention has been described using the example of a coolant condenser for an air conditioning system. However, it is to be noted that the heat exchanger according to the invention is also suitable for other application purposes.