Wind turbine rotor and method of assembly thereof

1. A wind turbine rotor, comprising:

a hub, a plurality of blades, at least one pitch system for rotating a blade substantially along its longitudinal axis, and at least one pitch retention system,

the at least one pitch retention system comprising a cam profile and a cam follower, wherein

one of the hub and the blade comprises the cam profile and the other of the hub and the blade comprises the cam follower,

the cam follower comprises a pushing member and a contact member, wherein the pushing member is arranged to push the contact member towards the cam profile,

the cam profile comprises a local depression, and

the cam follower and cam profile are arranged such that when the blade is in a pitch position at or below nominal wind speed, the contact member can be retained in the local depression.

2. The wind turbine rotor of claim 1 , wherein the contact member is a plain bearing that is in frictional contact with the cam profile when the blade is in or near the pitch position at or below nominal wind speed.

3. The wind turbine rotor of claim 1 , wherein the pushing member is an elastic member that is preloaded in compression.

4. The wind turbine rotor of claim 3 , wherein the elastic member is a bending bar.

5. The wind turbine rotor of claim 3 , wherein the elastic member is selected from the group consisting of a polymer spring, a metal spring or a group of springs.

6. The wind turbine rotor of claim 1 , wherein the cam follower comprises a support and a rocker and the pushing member is arranged between the support and the rocker.

7. The wind turbine rotor of claim 6 , wherein the contact member is mounted on a shaft rotatably housed inside the rocker.

8. The wind turbine rotor of claim 6 , wherein the cam follower further comprises a preloading bolt.

9. The wind turbine rotor of claim 8 , wherein the preloading bolt is arranged between two shafts, a first floating shaft comprising a threaded hole and mounted on the rocker and a second floating shaft comprising a hole and mounted on the support in such a manner that when the bolt is adjusted, the pushing member can be compressed.

10. The wind turbine rotor of claim 1 , wherein an inner pitch bearing ring comprises a reinforcement disc radially fixed to an inner side of the inner bearing ring and the cam profile is mounted on the reinforcement disc.

11. The wind turbine rotor of claim 10 , wherein an outer diameter of the reinforcement disc is slightly bigger than an inner diameter of the inner bearing ring such that the reinforcement disc and the inner bearing ring are shrink-fitted together.

12. The wind turbine rotor of claim 1 , wherein the cam profile is mounted on a pitch bearing ring or a reinforcement disc by an adapter.

13. The wind turbine rotor of claim 1 , wherein the cam profile is arranged in such a manner that the local depression is radially oriented with respect to a pitch bearing rotational axis.

14. The wind turbine rotor of claim 1 , wherein the cam profile is arranged in such a manner that the local depression is axially oriented with respect to a pitch bearing rotational axis.

15. A method of assembling the pitch retention system of claim 1 in the wind turbine rotor, the method comprising:

placing a pitch bearing in a pitch position corresponding to the nominal or below nominal wind speed;

fixing the cam profile to a pitch bearing ring or a reinforcement disc;

preloading the pushing member into compression;

placing the cam follower with the compressed pushing member in contact with the cam profile;

fixing the cam follower to another pitch bearing ring; and

removing the preload on the pushing member.

16. The method of claim 15 , wherein the cam profile is fixed to the blade and the cam follower is fixed to the hub.

17. The method of claim 15 , wherein the cam profile is fixed to hub and the cam follower is fixed to the blade.