Abstract:
A regulating flap arrangement ( 1 ) of an exhaust-gas turbocharger ( 3 ) having a flap shaft ( 5 ), which is guided by means of a bushing ( 10 ) in the turbine housing ( 2 ). A shaped sealing ring ( 13 ), as viewed in cross section, has at least one cavity ( 14 ). The shaped sealing ring ( 13 ) bears simultaneously against the first sealing surface ( 11 ) and against the second sealing surface ( 12 ), and in order to impart its sealing action, is compressed and deformed in the axial direction ( 15 ) of the flap shaft ( 5 ).

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a regulating flap arrangement of an exhaust-gas turbocharger provided with a turbine housing. 
     Description of the Related Art 
       FIG. 5  shows a regulating flap arrangement  100  which is already known. The figure shows a bushing  110  which is inserted into a turbine housing. A flap shaft  105  is rotatably mounted in said bushing  110 . A flap shaft lever  109  is fastened to one end of the flap shaft  105 . Said flap shaft lever  109  is connected to a flap plate  104 , for example for opening and closing a wastegate duct. The sealing between the flap shaft  105  and the bushing  110  is realized by means of two piston rings  101  which are arranged centrally in the flap shaft  105 . The regulating flap arrangement  100  which is already known is only inadequately capable of compensating the gaps and play that arise during operation owing to running play, tilting and rotation, such that the escape of exhaust gas with soot as leakage gas into the surroundings of the engine cannot be satisfactorily prevented. 
     It is therefore an object of the present invention to provide a regulating flap arrangement which permits sealing between the bushing and the flap shaft in a reliable manner. 
     BRIEF SUMMARY OF THE INVENTION 
     The sealing according to the invention is realized in each case by means of a shaped sealing ring which is arranged on the face-side end of the bushing. The shaped sealing ring can be compressed axially and, in so doing, provide sealing between the face-side end of the bushing and the outer flap lever or the inner flap shaft lever. It is alternatively possible for the shaped sealing ring to be compressed radially. In the case of the radial arrangement, the shaped sealing ring provides sealing between the flap shaft and an inwardly directed wall of the bushing. 
     In both cases, use is made according to the invention of a shaped sealing ring which, as viewed in its cross section, has at least one cavity. In particular, the shaped sealing ring is of V-shaped or S-shaped form. Owing to said cavity, it is possible for the shaped sealing ring to be compressed or deformed to an adequate extent in the axial or radial direction. The deformation of the shaped sealing ring results in a stress in the shaped sealing ring which counteracts the deforming force and which thus causes the shaped sealing ring to impart its sealing action. 
     The outer flap lever or the inner flap shaft lever may also be manufactured in one piece with the flap shaft. 
     The shaped sealing ring is in particular manufactured from metal and arranged in the secondary force flux in order to avoid inadmissibly intense compression. 
     By means of the new design of the regulating flap arrangement, it is achieved that the gaps and play arising during operation are compensated, and the escape of exhaust gas and soot is substantially prevented. The problem of the contamination of adjacent components with soot and the ingress of exhaust gas into the driver&#39;s cab is thereby also solved. Emissions into the environment are eliminated, and the exhaust gas and the soot can pass into the atmosphere only via the catalytic converter and the particle filter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Further details, advantages and features of the present invention become apparent from the following description of exemplary embodiments with reference to the drawing, in which: 
         FIG. 1  shows a perspective, sectional illustration of an exhaust-gas turbocharger according to the invention, 
         FIG. 2  shows a detail view of a regulating flap arrangement according to the invention as per a first exemplary embodiment, 
         FIG. 3  shows a detail view of the regulating flap arrangement according to the invention as per a second exemplary embodiment, 
         FIG. 4  shows a detail view of the regulating flap arrangement according to the invention as per a third exemplary embodiment, and 
         FIG. 5  shows a regulating flap arrangement according to the prior art. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates an exhaust-gas turbocharger  3  which has a turbine housing  2  in which a regulating flap arrangement  1  according to the invention, which will be explained in more detail with reference to  FIGS. 2 to 4 , can be arranged. 
       FIG. 1  shows the basic design of the regulating flap arrangement  1  composed of a flap plate  4  for opening and closing a wastegate duct. The flap plate  4  is connected via an inner flap shaft lever  9  to a flap shaft  5 . Said flap shaft  5  extends through the turbine housing  2  to the outside. An outer flap lever  6  is fastened to the outer end of the flap shaft  5 . The flap lever  6  is in turn connected to a regulating rod  7 . The regulating rod  7  is moved by means of a drive  8 . 
       FIG. 2  shows the first exemplary embodiment of the regulating flap arrangement  1  in detail. According to  FIG. 2 , a bushing  10  is situated in the turbine housing  2 . The flap shaft  5  is rotatably received in said bushing  10 . An axial direction  15  and a radial direction  16  are defined with reference to the flap shaft  5 . A groove  19  is formed on the face-side end of the bushing  10 . In this exemplary embodiment, the groove  19  is outwardly open in the radial direction  16  and is outwardly open in the axial direction  15 . A shaped sealing ring  13  is arranged in the groove  19 . 
     A face-side end of the bushing  10  constitutes a first sealing surface  11 . A second sealing surface  12  is situated opposite said first sealing surface  11 . The second sealing surface  12  is formed on the flap lever  6 . The shaped ring  13  provides sealing between said two sealing surfaces  11 ,  12 . 
     In this exemplary embodiment, the shaped sealing ring  13  is of V-shaped form. The V-shaped form comprises a first leg  17  and a second leg  18  as viewed in cross section. Said two legs  17 ,  18  are not parallel to one another, such that each leg  17 ,  18  has a free end and the other ends of the legs  17 ,  18  are connected to one another. The free ends of the legs  17 ,  18  bear against the sealing surfaces  11 ,  12 . The sealing action arises as a result of an axial compression and deformation of the shaped sealing ring  13  in the axial direction  15 . As a result of said deformation, a stress is generated in the shaped sealing ring  13  such that the shaped sealing ring  13  presses its legs  17 ,  18  against the sealing surfaces  11 ,  12 . 
     The groove  19  has a groove depth  20  in the axial direction  15 . The groove depth  20  is selected such that an excessively intense compression of the shaped sealing ring  13  is avoided. Specifically, before the shaped sealing ring  13  is destroyed, the flap lever  6  abuts against the bushing  10  and the shaped sealing ring  13  is securely received within the groove  19 . 
     The shaped sealing ring  13  has a cavity  14 . Owing to said cavity  14 , the shaped sealing ring  13  differs significantly from a simple seal of disk-shaped form. The cavity  14  is important for attaining an adequate deformation of the shaped sealing ring  13  when the latter is compressed, and thus also building up an adequate stress in the shaped sealing ring  13 . 
       FIG. 3  shows the regulating flap arrangement  1  as per the second exemplary embodiment. Identical or functionally identical components are denoted by the same reference numerals in all of the exemplary embodiments. The first two exemplary embodiments differ in that the shaped sealing ring is of S-shaped form in the second exemplary embodiment. As a result, the shaped sealing ring  13  has two cavities  14 . In the second exemplary embodiment, too, the shaped sealing ring  13  is compressed in the axial direction  15 . 
       FIG. 4  shows the regulating flap arrangement  1  as per the third exemplary embodiment. Identical or functionally identical components are denoted by the same reference numerals in all of the exemplary embodiments. In the third exemplary embodiment, the shaped sealing ring  13  is of V-shaped form with two legs  17 ,  18 . By contrast to the first exemplary embodiment, however, the V shape of the shaped sealing ring  13  in the third exemplary embodiment opens in the axial direction  15 . 
     In the third exemplary embodiment, the shaped sealing ring  13  is braced in the radial direction  16 . This requires a first radial sealing surface  11   a  on an inner wall, which faces toward the flap shaft  5 , of the bushing  10 . The second radial sealing surface  12   a  is correspondingly defined on the lateral surface of the flap shaft  5 . The groove  19  on the face-side end of the bushing  10  thus opens outwardly in the axial direction  15  and inwardly in the radial direction  16 . The shaped sealing ring  13  bears again with the free ends of its legs  17 ,  18  against the sealing surfaces  11   a ,  12   a.    
     Even though the invention has been explained above on the basis of the example of a regulating flap arrangement, the sealing arrangement may also be used in an exhaust-gas turbocharger with a variable turbine geometry. 
     In addition to the above written description of the invention, reference is hereby explicitly made to the diagrammatic illustration of the invention in  FIGS. 1 to 4  for additional disclosure thereof. 
     LIST OF REFERENCE SIGNS 
     
         
           1  Regulating flap arrangement 
           2  Turbine housing 
           3  Exhaust-gas turbocharger 
           4  Flap plate 
           5  Flap shaft 
           6  Outer flap lever 
           7  Regulating rod 
           8  Drive 
           9  Inner flap shaft lever 
           10  Bushing 
           11  First sealing surface 
           11   a  First radially sealing surface 
           12  Second sealing surface 
           12   a  Second radially sealing surface 
           13  Shaped seal 
           14  Cavity 
           15  Axial direction 
           16  Radial direction 
           17  First leg 
           18  Second leg 
           19  Groove 
           20  Groove depth 
           100  Regulating flap arrangement according to the prior art 
           101  Piston rings according to the prior art 
           104  Flap plate according to the prior art 
           105  Flap shaft according to the prior art 
           109  Flap shaft lever according to the prior art 
           110  Bushing according to the prior art