Compound main bearing arrangement for a wind turbine

1. A drive train of a wind turbine, the drive train comprising:

a rotatable hub;

a gearbox;

a rotatable rotor shaft extending between the rotatable hub and the gearbox; and,

a main bearing assembly supporting the rotatable rotor shaft, the main bearing assembly comprising a shaft flange and a main bearing housing enclosing one or more compound bearings, each of the one or more compound bearings comprising at least two axial thrust bearings, a radial bearing, and rotatable raceway components disposed adjacent the at least two axial thrust bearings and the radial bearing and configured as inner radial and axial exterior raceway surfaces, the shaft flange being attached to the rotatable raceway components and comprising a removable retainer flange configured to retain the one or more compound bearings.

2. The drive train of claim 1 , wherein the main bearing assembly is coupled to a main bearing pedestal extending from a main frame.

3. The drive train of claim 1 , wherein the one or more compound bearings further comprise;

a radial bearing pad disposed circumferentially around at least a portion of an inner surface of a fixed raceway annulus, and,

at least two axial thrust bearing pads disposed circumferentially around the rotatable rotor shaft on opposing sides of the fixed raceway annulus.

4. The drive train of claim 3 , wherein the rotatable rotor shaft is removably coupled to the rotatable hub at the shaft flange.

5. The drive train of claim 4 , wherein the at least two axial thrust bearings and the radial bearings comprises at least one of roller bearings, journal bearings, ball bearings or combinations thereof.

6. The drive train of claim 5 , wherein the journal bearings comprise at least one of hydrostatic bearings, hydrodynamic bearings, or combinations thereof.

7. The drive train of claim 6 , wherein the radial bearing comprises rolling elements and the at least two axial thrust bearings comprises journal bearings.

8. The drivetrain of claim 7 , wherein each of the at least two axial thrust bearings comprise at least one tilting pad arranged therewith so as to enable a tilting movement in a least one direction of rotation of the at least two axial thrust bearings.

9. The drive train of claim 8 , further comprising a lubricating mechanism, the lubricating mechanism comprising at least one fluid supply groove disposed in the fixed raceway annulus and at least one fluid supply hole configured through the fixed raceway annulus.

10. A wind turbine, comprising:

a tower;

a nacelle mounted atop the tower;

a generator and bearing pedestal coupled to a main frame within the nacelle;

a gearbox coupled to the generator via a generator shaft;

a rotatable hub;

a rotatable rotor shaft extending between the rotatable hub and the gearbox; and,

a main bearing assembly coupled with the bearing pedestal and supporting the rotatable rotor shaft, the main bearing assembly comprising a fluted portion and a main bearing housing enclosing one or more compound bearings, each of the one or more compound bearings comprising at least two axial thrust bearings, a radial bearing, and rotatable raceway components disposed adjacent the at least two axial thrust bearings and the radial bearing and configured as inner radial and axial exterior raceway surfaces, the fluted portion being attached to the rotatable raceway components and comprising a removable retainer flange configured to retain the one or more compound bearings.

11. The wind turbine of claim 10 , wherein the one or more compound bearings further comprise;

a radial bearing pad disposed circumferentially around at least a portion of an inner surface of a fixed raceway annulus, and,

at least two axial thrust bearing pads disposed circumferentially around the rotatable rotor shaft on opposing sides of the fixed raceway annulus.

12. The wind turbine of claim 11 , wherein the rotatable rotor shaft is removably coupled to the rotatable hub at the shaft flange.

13. The wind turbine of claim 12 , wherein the at least two axial thrust bearings and the radial bearing comprise at least one of roller bearings, journal bearings, ball bearings or combinations thereof.

14. The wind turbine of claim 13 , wherein the radial bearing comprises rolling elements and the at least two axial thrust bearings comprises journal bearings.

15. The wind turbine of claim 14 , wherein each of the at least two axial thrust bearings comprise at least one tilting pad arranged therewith so as to enable a tilting movement in a least one direction of rotation of the at least two axial thrust bearings.

16. The wind turbine of claim 15 , further comprising a lubricating mechanism, the lubricating mechanism comprising at least one fluid supply groove disposed in the fixed raceway annulus and at least one fluid supply hole configured through the fixed raceway annulus.