Device for controlling pivotable vanes of a turbo-machine

1. A control device for controlling pivotable vanes of a turbo-machine, comprising:

a plurality of pivotable vanes distributed in azimuth over at least 90° around an axis of the turbo-machine, the pivotable vanes being oriented substantially radially relative to the axis of the turbo-machine; and

a control ring portion to control pivoting of the vanes, each vane being connected to the control ring portion by a link, the control ring portion being held around the axis of the turbo-machine by the links;

wherein at least two of the links are connected to the ring portion by respective ball-joint connections, with other links among the links being connected to the ring portion via respective sliding pivot connections, and

wherein the two ball-joint connections are spaced apart in azimuth by about 90°.

2. A control device according to claim 1 , wherein the two of the links connected to the ring portion via the respective ball-joint connections are rigid, while the other links among the links connected to the ring portion via the respective sliding pivot connections are more flexible so as to be elastically deformable.

3. A control device according to claim 2 , wherein the more flexible links are elastically deformable in torsion and in bending.

4. A control device according to claim 1 , wherein one of the links is connected to the ring portion via a pivot-only connection.

5. A turbo-machine comprising a pivotable vane control device according to claim 1 .

6. A control device according to claim 1 , wherein the ring portion is spaced apart from a stator that mounts the pivotable vanes in a direction along the axis of the turbo-machine.

7. A control device for controlling pivotable vanes of a turbo-machine, comprising:

a plurality of pivotable vanes distributed in azimuth over at least 90° around an axis of the turbo-machine, the pivotable vanes being oriented substantially radially relative to the axis of the turbo-machine; and

a control ring portion to control pivoting of the vanes, each vane being connected to the control ring portion by a link, the control ring portion being held around the axis of the turbo-machine by the links;

wherein at least two of the links are connected to the ring portion by respective ball-joint connections, with other links among the links being connected to the ring portion via respective sliding pivot connections,

wherein the two of the links connected to the ring portion via the respective ball-joint connections are rigid, while the other links among the links connected to the ring portion via the respective sliding pivot connections are more flexible so as to be elastically deformable.

8. A control device according to claim 7 , wherein he two ball-joint connections are spaced apart in azimuth by about 90°.

9. A control device according to claim 7 , wherein the more flexible links are elastically deformable in torsion and in bending.

10. A control device according to claim 7 , wherein one of the links is connected to the ring portion via a pivot-only connection.

11. A turbo-machine comprising a pivotable vane control device according to claim 7 .

12. A control device according to claim 7 , wherein the ring portion is spaced apart from a stator that mounts the pivotable vanes in a direction along the axis of the turbo-machine.

13. A control device for controlling pivotable vanes of a turbo-machine, comprising:

a plurality of pivotable vanes distributed in azimuth over at least 90° around an axis of the turbo-machine, the pivotable vanes being oriented substantially radially relative to the axis of the turbo-machine; and

a control ring portion to control pivoting of the vanes, each vane being connected to the control ring portion by a link, the control ring portion being held around the axis of the turbo-machine by the links;

wherein at least two of the links are connected to the ring portion by respective ball-joint connections, with other links among the links being connected to the ring portion via respective sliding pivot connections,

wherein one of the links is connected to the ring portion via a pivot-only connection.

14. A control device according to claim 13 , wherein the two ball-joint connections are spaced apart in azimuth by about 90°.

15. A control device according to claim 13 , wherein the two of the links connected to the ring portion via the respective ball-joint connections are rigid, while the other links among the links connected to the ring portion via the respective sliding pivot connections are more flexible so as to be elastically deformable.

16. A control device according to claim 15 , wherein the more flexible links are elastically deformable in torsion and in bending.

17. A turbo-machine comprising a pivotable vane control device according to claim 13 .

18. A control device according to claim 13 , wherein the ring portion is spaced apart from a stator that mounts the pivotable vanes in a direction along the axis of the turbo-machine.