Wind turbine bearings

A dual pitch bearing configuration for coupling a rotor blade to a hub of a wind turbine, the dual pitch bearing configuration comprising:

• a static shaft including a wall thickness defining an interior surface and an exterior surface, the static shaft extending axially from the hub;
• a first pitch bearing coupled to the interior surface of the static shaft, the first pitch bearing including an inner bearing race, an outer bearing race and a plurality of rolling elements disposed between the inner bearing race and the outer bearing race;
• a second pitch bearing coupled to the exterior surface of the static shaft, the second pitch bearing including an inner bearing race, an outer bearing race and a plurality of rolling elements disposed between the inner bearing race and the outer bearing race, the second pitch bearing disposed radially a distance LR from the first pitch bearing, where LR is equal to the wall thickness of the static shaft, and axially a distance LA from the first pitch bearing along the static shaft, thereby minimizing moment loading on the first pitch bearing and the second pitch bearing;
• and
• the first pitch bearing and the second pitch bearing disposed within a blade root of the rotor blade.

A wind turbine comprising:

• a tower;
• a hub;
• at least one rotor blade rotatably connected to the hub, the at least one rotor blade rotatable in response to wind impinging upon said at least one rotor blade;
• and
• a dual pitch bearing configuration coupling the at least one rotor blade to the hub, the dual pitch bearing configuration comprising:
• a first pitch bearing including an inner bearing race, an outer bearing race and a plurality of rolling elements disposed between the inner bearing race and the outer bearing race;
• and
• at least one additional pitch bearing including an inner bearing race, an outer bearing race and a plurality of rolling elements disposed between the inner bearing race and the outer bearing race,
• wherein the first pitch bearing is coupled to an interior surface of a static shaft and the at least one additional pitch bearing is coupled to an exterior surface of the static shaft,
• wherein the inner bearing race of the first pitch bearing and the outer bearing race of the at least one additional pitch bearing are coupled to a bearing sleeve disposed in the at least one rotor blade rotor blade and rotatable with the at least one rotor blade rotor blade, and
• wherein the at least one additional pitch bearing is disposed radially a distance LR from the first pitch bearing and axially a distance LA from the first pitch bearing along the static shaft, thereby minimizing moment loading on the first pitch bearing and the at least one additional pitch bearing.