An exhaust-gas turbocharger (1) having a turbine (2), which has a turbine wheel (3) surrounded by an intake duct (4), and having a VTG cartridge (5), which has a disk (6) and a vane bearing ring (7), which delimit the intake duct (4), and which has a plurality of vanes (8), which are arranged in the intake duct (4) and are mounted in the vane bearing ring (7) by way of rotatable vane shafts (9), which are connected to vane levers (10), the lever heads (11) of which engage into associated grooves (12) in a unison ring (13), which surrounds the vane bearing ring (7) on the outside, and which has an adjusting lever (14) which is operatively connected to an adjusting shaft (15) in order to transmit an adjusting torque to the unison ring (13). The adjusting lever (14) is of planar configuration.

The invention relates to an exhaust-gas turbocharger according to the preamble of claim1.

In the case of such an exhaust-gas turbocharger, provision is made of a variable turbine geometry (VTG), in which guide vanes are adjusted by means of a unison ring, which can be rotated by means of an adjusting shaft.

It is an object of the present invention to provide an exhaust-gas turbocharger of the type described in the preamble of claim1, in which the bearing forces in the system of the VTG and in particular of the adjusting shaft can be reduced.

This object is achieved by the features of claim1.

The dependent claims contain advantageous developments of the invention.

Claims7and8define a VTG cartridge according to the invention as an object which can be marketed independently.

FIG. 1shows a schematically greatly simplified basic illustration of an exhaust-gas turbocharger1according to the invention, which has a charger axis of rotation L.

The exhaust-gas turbocharger1also has a turbine2, which comprises a turbine wheel3surrounded by an intake duct4, which is provided with a so-called VTG cartridge5. This VTG cartridge5will be described in detail hereinbelow with reference toFIGS. 2 to 4.

The exhaust-gas turbocharger1also of course has all the other common parts of an exhaust-gas turbocharger, such as a rotor20, which is mounted rotatably in a bearing housing21and which bears the turbine wheel3at one end and a compressor wheel19of a compressor18at the other end. These parts are likewise shown only in schematically greatly simplified form inFIG. 1, since they are not of importance for explaining the principles of the present invention.

The VTG cartridge, which, as mentioned, will be explained in detail hereinbelow with reference toFIGS. 2 to 4, is likewise shown in greatly schematically simplified form.

A VTG cartridge is understood to mean a structural unit which, between a vane bearing ring7and a disk6, delimits an intake duct4for the passage of exhaust gases to the turbine wheel3. Furthermore, a VTG cartridge5of this type has a plurality of vanes, which are arranged in the intake duct4and of whichFIGS. 2 and 4show one vane designated8as a representative example of all vanes bearing the corresponding reference numeral. The vanes8can be moved rotatably in the vane bearing ring7between a closed and an open position. For this purpose, the vanes8have vane shafts9each having an axis of rotation. The vane shafts9in turn are connected to vane levers10, of which two vane levers are denoted in each case inFIG. 2with the reference numeral10. AsFIG. 2shows, the embodiment shown there has ten such, preferably cranked vane levers, in each case of identical design, and correspondingly ten vanes8.

Each vane lever10has a lever head11, which engages into an associated groove12in a unison ring13.FIG. 2shows in this respect that the unison ring13surrounds the vane bearing ring7on the outside, i.e. along the outer circumference thereof.

For radially mounting the unison ring13, provision is made of a radial bearing, which according to the invention is formed by the vane levers10. For this purpose, the vane levers10are formed as rolling levers, the lever heads11of which are supported in the grooves12in the unison ring13.FIGS. 2 and 4show that the grooves12are arranged in a plane that is offset with respect to the bearing plane of the vane levers10on the vane bearing ring7, which is the reason for the cranked configuration of the vane levers10in this embodiment.

As can be seen whenFIGS. 2 to 4are viewed in combination, the exhaust-gas turbocharger1according to the invention, or the VTG cartridge5according to the invention, also has an adjusting lever14, which is operatively connected to an adjusting shaft15(which can be seen inFIG. 3) for transmitting an adjusting torque to the unison ring13. The adjusting shaft15can be actuated by means of a suitable actuator which is known per se and is not shown in detail inFIGS. 2 to 4, since it is not necessary for the purposes of explaining the principles of the present invention.

However,FIGS. 2 to 4do illustrate that the adjusting lever14is of planar configuration. Here, the adjusting lever14has a first end region14A, which in the assembled state is adjacent to the adjusting lever13and which has a groove16that engages around a positioning pin17. The positioning pin17is fixed on the unison ring13, preferably is welded onto the unison ring13.

As can also be seen fromFIGS. 2 to 4, the groove16is open on one side, which results in a fork-like structure of the first end region14A, as can be seen in particular from the illustration presented inFIG. 3.

The adjusting lever14also has a second end region14B, which is arranged adjacent to the vane bearing ring7, in particular above the vane bearing ring7, and is provided with a recess17in which the adjusting shaft15is fixed. InFIG. 2, only the recess17can be seen, whereasFIG. 3shows a schematically simplified representation of the arrangement of the adjusting shaft15in the recess17. The adjusting shaft15may for example be welded in the recess17.

In addition to the above written disclosure, reference is hereby explicitly made to the illustrative representation of the invention inFIGS. 1 to 4to supplement the disclosure of the invention.

LIST OF REFERENCE SIGNS

7Vane bearing ring

14A,14B End regions of the unison ring

L Charger longitudinal axis