Drive assembly

Abstract

A drive assembly for a wind turbine includes a rotor hub, supporting structure such as a turbine nacelle, a planetary type gear transmission unit comprising sun, planet and ring gears and a planet carrier, the ring gear being non-rotatably secured to the supporting structure, a main bearing which is a double taper bearing and rotatably supports the rotor hub relative to the ring gear and supporting structure, and the drive assembly comprising two substantially independent force transmission paths for transmission of forces reacting with forces exerted by the wind turbine rotor hub, a first of the force transmission paths acting from the rotor hub via the main bearing to the supporting structure primarily for transmission of overhang load forces and bending moment forces and a second of the force transmission paths acting from the rotor hub via the planet carrier primarily for transmission of rotational forces.

1 - 26 . (cancelled)  
     
     
         27 . Drive assembly for a wind turbine comprising a rotor hub, supporting structure such as a turbine nacelle, a planetary type gear transmission unit comprising sun, planet and ring gears and a planet carrier, said ring gear being non-rotatably secured to said supporting structure, a main bearing which is a double taper bearing and rotatably supports the rotor hub relative to said ring gear and supporting structure, and said drive assembly comprising two substantially independent force transmission paths for transmission of forces reacting with forces exerted by the wind turbine rotor hub, a first of said force transmission paths acting from the rotor hub via said main bearing to the supporting structure primarily for transmission of overhang load forces and bending moment forces and a second of said force transmission paths acting from the rotor hub via said planet carrier primarily for transmission of rotational forces.  
     
     
         28 . A drive assembly according to  claim 27 , wherein said main bearing additionally rotatably supports the planet carrier relative to said ring gear and supporting structure.  
     
     
         29 . A drive assembly according to  claim 27 , wherein said double taper bearing comprises a single outer bearing ring.  
     
     
         30 . A drive assembly according to  claim 29 , wherein the rotor hub is rigidly secured relative to said single outer bearing ring.  
     
     
         31 . A drive assembly according to  claim 27 , wherein the double taper bearing comprises rollers arranged in an ◯ configuration in which the rollers of one series increase in diameter in a direction away from the rollers of the other series of the pair.  
     
     
         32 . A drive assembly according to  claim 27 , wherein, as considered in an axial direction parallel with the axis of rotation of the planet carrier, the ring gear is substantially aligned axially with the main bearing.  
     
     
         33 . A drive assembly according to  claim 27 , wherein the main bearing comprises an inner ring bearing surface of a diameter greater than that of the toothed surface of the ring gear.  
     
     
         34 . A drive assembly according to  claim 27 , wherein the sun, planet and ring gears lie in a transverse plane which contains said main bearing.  
     
     
         35 . A drive assembly according to  claim 27 , wherein at all radial positions inwards of the toothed surface of the ring gear the second force transmission path is substantially independent of the first force transmission path.  
     
     
         36 . A drive assembly according to  claim 27 , wherein the second of said force transmission paths comprises a radially extending torque transmission member which is torsionally stiff but relatively compliant in an axial direction parallel with the axis about which the rotational forces act.  
     
     
         37 . A drive assembly according to  claim 27 , wherein the outer ring of the main bearing is connected or adapted for connection to a wind turbine rotor hub.  
     
     
         38 . A drive assembly according to  claim 27 , wherein the main bearing and gear transmission unit are of an integrated construction.  
     
     
         39 . A drive assembly according to  claim 38  wherein the ring gear provides a bearing surface for rotatable bearing components of the main bearing.  
     
     
         40 . A drive assembly according to  claim 27 , wherein an inner ring of the main bearing is supported by the ring gear.  
     
     
         41 . A drive assembly according to  claim 40 , wherein the ring gear provides axial and radial locations for the main bearing.  
     
     
         42 . A drive assembly according to  claim 41 , wherein the ring gear has a radially outer surface of a stepped profile to define a shoulder for axial location of an inner bearing ring of the main bearing.  
     
     
         43 . A drive assembly according to  claim 41 , wherein the inner bearing ring is secured axially between said shoulder and said supporting structure.  
     
     
         44 . A drive assembly according to  claim 27 , wherein the ring gear is provided with a reinforcing ring.  
     
     
         45 . A drive assembly according to  claim 44 , wherein said reinforcing ring extends axially and or radially beyond the toothed surface of the ring gear.  
     
     
         46 . A drive assembly according to  claim 44 , wherein the reinforcing ring provides an axial location of the main bearing.  
     
     
         47 . A drive assembly according to  claim 27 , wherein the main bearing is mounted on a flange which connects the ring gear to the supporting structure.  
     
     
         48 . A drive assembly according to  claim 27 , wherein the gear transmission unit is adapted to support an electrical generator.  
     
     
         49 . A wind turbine comprising rotors, an electrical generator and a drive assembly according to  claim 27 .  
     
     
         50 . A gear transmission unit for use in a wind turbine to transmit forces from a rotor hub to a generator, said gear transmission unit comprising a planetary type gear transmission unit comprising sun, planet and ring gears and a planet carrier, said ring gear being adapted for non-rotatably securing to supporting structure such as a turbine nacelle, and a main bearing of a double taper type.