In exhaust-gas turbochargers, use is in some cases made of a so-called variable turbine geometry (VTG) for regulating the exhaust-gas mass flow through the turbine. A VTG of said type is actuated for example by means of a pneumatic actuator. For this purpose, the actuator is connected via a regulating rod to an outside lever of the VTG.

The setting of the VTG is on the one hand realized by means of an end piece which is held in the set position by two lock nuts. It is also known for a knurled nut to be used for the height compensation of the actuator or of the control capsule, which knurled nut is subsequently secured by means of a lock nut.

The use of one or more lock nuts in exhaust-gas turbochargers such as are known for example from US 6,895,947 B2 however has the disadvantage that the control capsule diaphragm can easily be twisted during the locking of the nut. Furthermore, an oblique position of the setting piece may easily arise.

It is therefore an object of the present invention to provide a regulating rod of the type indicated in the preamble of claim 1 by means of which the disadvantages of the prior art can be eliminated.

This object is achieved by the features of claim 1.

The regulating rod according to the invention combines the advantages of a knurled nut without the need to resort to the disadvantageous locking of the nut as explained above. This is because, after the setting of the control capsule play by means of the knurled nut, the set effective length of the rod part of the regulating rod can be secured in cohesive fashion by means of a fastening portion of the end piece. Here, "effective length" is to be understood to mean the length which, after the setting of the actuator and the fixing of the end piece, actively serves for transmission of force.

The dependent claims contain advantageous developments of the invention. Further details, advantages and features of the present invention become apparent from the following description of an exemplary embodiment with reference to the drawing, in which: figure 1 is a perspective illustration of an exhaust-gas turbocharger according to the invention with a regulating rod according to the invention in an installed state, and

figure 2 shows a perspective view of an end piece of the regulating rod as per figure 1.

Figure 1 illustrates an exhaust-gas turbocharger 18 which has a compressor 16 and a turbine 15. A bearing housing 17 is arranged, in the conventional way, between the compressor 16 and the turbine 15.

The exhaust-gas turbocharger 18 is equipped with a variable turbine geometry, of which only an outside lever 19 is visible in figure 1. A variable turbine geometry of said type is understood to mean a structural unit which, between a vane bearing ring and a disk, delimits an inflow duct for the passage of exhaust gases to the turbine wheel of the turbine 15. A VTG of said type also has a multiplicity of vanes which are arranged in the inflow duct. The vanes can be moved rotatably in the vane bearing ring between a closed and an open position. For this purpose, the vanes have vane shafts which are connected to vane levers. Each vane lever in turn has a lever head which engages into an adjusting ring. For the adjustment of the vanes, the adjusting ring is actuated by means of an actuator 14, for example of a pneumatic control capsule. For this purpose, the control capsule 14 has a regulating rod 1. The regulating rod 1 has a rod part which, at the inner end not visible in figure 1 , is connected to a diaphragm of the control capsule. The other end which is visible in figure 1, or the visible end region 3, is provided with an external thread, which external thread is however not illustrated in figure 1 because the end region 3 is screwed into an end piece 4.

Said end piece 4 is shown in detail and in an enlarged illustration in figure 2. The end piece 4 is provided with a receiving recess 5 in which a setting piece 6, in the form of a knurled nut in the example, is arranged and guided. The setting piece 6 has an internal thread into which the external thread of the end region 3 of the rod part 2 can be screwed.

As can be seen in particular from the enlarged illustration of figure 2, the end piece 3 has a fastening portion 7. In the embodiment illustrated in figures 1 and 2, said fastening portion 7 is formed by a weld window 8 which is delimited by two webs 8A and 8B which run parallel to one another and which merge into one another at their end regions. Figures 1 and 2 show that said weld window 8 runs across the knurled nut 6.

The end piece 7 is assembled from two sheet-metal halves 9 and 10 which delimit a cavity for receiving the free end region 3 of the rod part 2. Said cavity is not visible in figures 1 and 2 but forms a cylinder which is formed by the two semi-circular bulged regions 9A and 1 OA.

Figure 2 in particular also shows that the end piece 4 is provided with a compensating ball joint 11 which is arranged in a receiving recess 12 of a flattened connection region 13 of the end piece 4. Said flattened connection region 13 adjoins the cylindrical cavity or the spherical regions 9 A and 10A, as can be seen in detail from figure 2.

For the connection of the two sheet-metal halves, it is possible in principle to use any suitable type of connecting means. Particular preference is given to welded connections, brazed connections, riveted connections or else screw connections, or in principle also combinations of said connection techniques.

To set the VTG or the control capsule 14, the free end region 3 is screwed with its external thread into the internal thread of the knurled nut 6. The fine adjustment is then performed by actuation of the knurled nut 6. When the setting process is complete, the final position is fixed by means of the fastening portion 7. In the particularly preferred exemplary embodiment illustrated in figures 1 and 2, this means that the weld window 8 is filled with weld filler such that the knurled nut 6 is non- detachably fixed.

By means of the additionally provided compensating ball joint 11, it is possible for an axial play of the control capsule to be ensured and the assembly of the arrangement as a whole to be facilitated.

In addition to the above written disclosure of the invention, reference is explicitly made to figures 1 and 2 to supplement the disclosure of the invention. LIST OF REFERENCE SIGNS

1 Regulating rod

2 Rod part

3 End region

4 End piece

5 Receiving recess

6 Setting piece

7 Fastening portion

8 Weld window

8A, 8B Webs

9 Sheet-metal half

9A Semi-circular sheet-metal half portion

10 Sheet-metal half

10A Semi-circular sheet-metal half portion

11 Compensating ball joint

12 Receiving recess

13 Connection region

14 Actuator (control capsule)

15 Turbine

16 Compressor

17 Bearing housing

18 Exhaust-gas turbocharger

19 Outside lever