Regulating flap arrangement of an exhaust-gas turbocharger

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).

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. 5shows a regulating flap arrangement100which is already known. The figure shows a bushing110which is inserted into a turbine housing. A flap shaft105is rotatably mounted in said bushing110. A flap shaft lever109is fastened to one end of the flap shaft105. Said flap shaft lever109is connected to a flap plate104, for example for opening and closing a wastegate duct. The sealing between the flap shaft105and the bushing110is realized by means of two piston rings101which are arranged centrally in the flap shaft105. The regulating flap arrangement100which 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'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.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates an exhaust-gas turbocharger3which has a turbine housing2in which a regulating flap arrangement1according to the invention, which will be explained in more detail with reference toFIGS. 2 to 4, can be arranged.

FIG. 1shows the basic design of the regulating flap arrangement1composed of a flap plate4for opening and closing a wastegate duct. The flap plate4is connected via an inner flap shaft lever9to a flap shaft5. Said flap shaft5extends through the turbine housing2to the outside. An outer flap lever6is fastened to the outer end of the flap shaft5. The flap lever6is in turn connected to a regulating rod7. The regulating rod7is moved by means of a drive8.

FIG. 2shows the first exemplary embodiment of the regulating flap arrangement1in detail. According toFIG. 2, a bushing10is situated in the turbine housing2. The flap shaft5is rotatably received in said bushing10. An axial direction15and a radial direction16are defined with reference to the flap shaft5. A groove19is formed on the face-side end of the bushing10. In this exemplary embodiment, the groove19is outwardly open in the radial direction16and is outwardly open in the axial direction15. A shaped sealing ring13is arranged in the groove19.

A face-side end of the bushing10constitutes a first sealing surface11. A second sealing surface12is situated opposite said first sealing surface11. The second sealing surface12is formed on the flap lever6. The shaped ring13provides sealing between said two sealing surfaces11,12.

In this exemplary embodiment, the shaped sealing ring13is of V-shaped form. The V-shaped form comprises a first leg17and a second leg18as viewed in cross section. Said two legs17,18are not parallel to one another, such that each leg17,18has a free end and the other ends of the legs17,18are connected to one another. The free ends of the legs17,18bear against the sealing surfaces11,12. The sealing action arises as a result of an axial compression and deformation of the shaped sealing ring13in the axial direction15. As a result of said deformation, a stress is generated in the shaped sealing ring13such that the shaped sealing ring13presses its legs17,18against the sealing surfaces11,12.

The groove19has a groove depth20in the axial direction15. The groove depth20is selected such that an excessively intense compression of the shaped sealing ring13is avoided. Specifically, before the shaped sealing ring13is destroyed, the flap lever6abuts against the bushing10and the shaped sealing ring13is securely received within the groove19.

The shaped sealing ring13has a cavity14. Owing to said cavity14, the shaped sealing ring13differs significantly from a simple seal of disk-shaped form. The cavity14is important for attaining an adequate deformation of the shaped sealing ring13when the latter is compressed, and thus also building up an adequate stress in the shaped sealing ring13.

FIG. 3shows the regulating flap arrangement1as 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 ring13has two cavities14. In the second exemplary embodiment, too, the shaped sealing ring13is compressed in the axial direction15.

FIG. 4shows the regulating flap arrangement1as 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 ring13is of V-shaped form with two legs17,18. By contrast to the first exemplary embodiment, however, the V shape of the shaped sealing ring13in the third exemplary embodiment opens in the axial direction15.

In the third exemplary embodiment, the shaped sealing ring13is braced in the radial direction16. This requires a first radial sealing surface11aon an inner wall, which faces toward the flap shaft5, of the bushing10. The second radial sealing surface12ais correspondingly defined on the lateral surface of the flap shaft5. The groove19on the face-side end of the bushing10thus opens outwardly in the axial direction15and inwardly in the radial direction16. The shaped sealing ring13bears again with the free ends of its legs17,18against the sealing surfaces11a,12a.

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 inFIGS. 1 to 4for additional disclosure thereof.

LIST OF REFERENCE SIGNS

1Regulating flap arrangement2Turbine housing3Exhaust-gas turbocharger4Flap plate5Flap shaft6Outer flap lever7Regulating rod8Drive9Inner flap shaft lever10Bushing11First sealing surface11aFirst radially sealing surface12Second sealing surface12aSecond radially sealing surface13Shaped seal14Cavity15Axial direction16Radial direction17First leg18Second leg19Groove20Groove depth100Regulating flap arrangement according to the prior art101Piston rings according to the prior art104Flap plate according to the prior art105Flap shaft according to the prior art109Flap shaft lever according to the prior art110Bushing according to the prior art