Waste gas heat exchanger

Abstract

The invention relates to a heat exchanger, especially a heat exchanger for motor vehicles, comprising a bank of tubes through which a gaseous medium flows and around which a liquid coolant flows. The ends of said tubes are received in tube plates and are connected to the same in a material fit. The inventive heat exchanger also comprises a housing jacket which surrounds the bank of tubes and is connected, at the end thereof, to the tube plates. A coolant flows through said housing jacket. The tubes ( 5 ), tube plates ( 3, 7 ) and housing jacket ( 2 ) are produced from a heat-resistant and corrosion-resistant metallic alloy. According to the invention, the housing jacket ( 2 ) comprises at least one surrounding expansion flange ( 4 ).

1 . A heat exchanger, in particular an exhaust gas heat exchanger for motor vehicles, having a bank of tubes through which a gaseous medium flows and around which a liquid coolant flows, and the tubes of which are held by their tube ends in tube plates and are connected thereto with a cohesive material joint, and having a housing jacket which surrounds the bank of tubes and is connected on the end side to the tube plates with a cohesive material joint and through which the coolant flows, tubes ( 5 ), tube plates ( 3 ,  7 ) and housing jacket ( 2 ) being produced from a heat-resistant and corrosion-resistant metallic alloy, characterized in that the housing jacket ( 2 ) has at least one encircling expansion bead ( 4 ).  
     
     
         2 . The heat exchanger as claimed in  claim 1 , characterized in that the housing jacket ( 2 ) is of integral design.  
     
     
         3 . The heat exchanger as claimed in  claim 1  or  2 , characterized in that the housing jacket ( 2 ) is produced from a welded tube.  
     
     
         4 . The heat exchanger as claimed in  claim 1 ,  2  or  3 , characterized in that the housing jacket has a noncircular cross section ( 10 ,  11 ,  12 ,  13 ).  
     
     
         5 . The heat exchanger as claimed in one of the preceding claims, characterized in that the expansion bead ( 4 ) is produced by internal high pressure forming (IHF) of the housing jacket ( 2 ).  
     
     
         6 . The heat exchanger as claimed in one of the preceding claims, characterized in that the expansion bead ( 4 ) is produced by axial compression of the housing jacket ( 2 ).  
     
     
         7 . The heat exchanger as claimed in one of the preceding claims, characterized in that the housing jacket ( 2 ) has a wall thickness of 0.5≦s≦2.5 mm, preferably of s≈1.5 mm.  
     
     
         8 . The heat exchanger as claimed in  claim 7 , characterized in that the expansion bead ( 4 ) has a height h of 2≦h≦10 mm, in particular of h≈6 mm.  
     
     
         9 . The heat exchanger as claimed in  claim 7  or  8 , characterized in that the expansion bead ( 4 ) has a width b of 4≦b≦8 mm, in particular of b≈6 mm.  
     
     
         10 . The heat exchanger as claimed in one of claims  7 ,  8  or  9 , characterized in that the ratio of width to height, i.e. b: h≈1.  
     
     
         11 . The heat exchanger as claimed in one of  claims 7  to  10 , characterized in that the bead ( 4 ) has a bending radius of R3≈s.  
     
     
         12 . A method for producing an expansion bead ( 4 ) in a tubular housing jacket ( 2 ,  20 ), in particular having a noncircular cross section, characterized by the following method steps: 
 provision of a housing jacket ( 2 ,  20 ) which is cut to size,    insertion of the housing jacket ( 2 ,  20 ) into an IHF mold ( 21 ,  22 ,  23 ) and closing the mold,    filling the mold and the housing jacket ( 2 ,  20 ) with a liquid pressure medium,    deformation of the housing jacket ( 2 ,  20 ) by building up internal high pressure and producing a preliminary form ( 24 ) of the bead (first deformation step),    reduction of the internal high pressure and    production of the final form of the expansion bead ( 4 ) by axial compression of the housing jacket ( 2 ,  20 ) in a second deformation step.    
     
     
         13 . The method as claimed in  claim 12 , characterized in that the first method step 
 production of a preliminary form ( 24 ) of the bead, and the second method step    axial compression of the housing jacket ( 2 ,  20 ) are carried out in a mold.