A main bearing housing for a wind turbine comprising a bearing arrangement having a sump located in a floor region of the main bearing housing. The sump comprises a floor pan surrounded by a side wall and includes an overflow arrangement configured to permit fluid to spill from the sump. The overflow arrangement comprises a spill passage configured with a spill inlet at or near the floor pan of the sump and a spill outlet located in a position between the spill inlet and an upper edge of the sump side wall. An advantage of the invention is that since the spill passage is fed with oil from a position that is close to the bottom of the sump, debris and sediment at the bottom of the sump tends to be entrained with the flow of oil and so tends not to collect at the bottom of the sump. The lubrication system therefore is able to clean the oil more effectively because the debris and sediment is encouraged to circulate around the lubrication system.

A main bearing housing for a wind turbine comprising a bearing arrangement having a sump located in a floor region of the main bearing housing. The sump comprises a floor pan surrounded by a side wall and includes an overflow arrangement configured to permit fluid to spill from the sump. The overflow arrangement comprises a spill passage configured with a spill inlet at or near the floor pan of the sump and a spill outlet located in a position between the spill inlet and an upper edge of the sump side wall. An advantage of the invention is that since the spill passage is fed with oil from a position that is close to the bottom of the sump, debris and sediment at the bottom of the sump tends to be entrained with the flow of oil and so tends not to collect at the bottom of the sump. The lubrication system therefore is able to clean the oil more effectively because the debris and sediment is encouraged to circulate around the lubrication system.

In a main bearing replacement method for a wind turbine power generation facility including a nacelle, a rotor head rotatably supported by the nacelle, a drive shaft to which rotation of the rotor head is transmitted, a main bearing disposed between the rotor head and the nacelle, and a coupling connecting the rotor head and the drive shaft on a radially inner side of the main bearing, the wind turbine power generation facility includes a main bearing sleeve fitted and fixed to an inner ring of the main bearing and mounted with the rotor head, and the main bearing is replaced at least while the main bearing sleeve is fitted and fixed to the inner ring of the main bearing.

In a main bearing replacement method for a wind turbine power generation facility including a nacelle, a rotor head rotatably supported by the nacelle, a drive shaft to which rotation of the rotor head is transmitted, a main bearing disposed between the rotor head and the nacelle, and a coupling connecting the rotor head and the drive shaft on a radially inner side of the main bearing, the wind turbine power generation facility includes a main bearing sleeve fitted and fixed to an inner ring of the main bearing and mounted with the rotor head, and the main bearing is replaced at least while the main bearing sleeve is fitted and fixed to the inner ring of the main bearing.

A wind turbine rotor blade assembly which incorporates automatic-aerodynamic control of the blade pitch angle is disclosed. The airfoil of the rotor blade (110) is free to rotate about a strategically located longitudinal blade axis which forms the spar stub (115) and is connected to the hub (120) of a horizontal axis wind turbine. The location of this blade axis is precisely set with respect to the turbine blade's aerodynamic center and center of mass. By further incorporating a reflexed airfoil with positive pitching moment this arrangement aerodynamically induces an automatic and self-regulating alignment of the rotor blade pitch such that the airfoil is always operating at or near optimal angle of attack. Details are disclosed on these strategic relationships which enable the successful operation of the new blade design.

A wind turbine rotor blade assembly which incorporates automatic-aerodynamic control of the blade pitch angle is disclosed. The airfoil of the rotor blade (110) is free to rotate about a strategically located longitudinal blade axis which forms the spar stub (115) and is connected to the hub (120) of a horizontal axis wind turbine. The location of this blade axis is precisely set with respect to the turbine blade's aerodynamic center and center of mass. By further incorporating a reflexed airfoil with positive pitching moment this arrangement aerodynamically induces an automatic and self-regulating alignment of the rotor blade pitch such that the airfoil is always operating at or near optimal angle of attack. Details are disclosed on these strategic relationships which enable the successful operation of the new blade design.

A blade root cover segment suitable for fitting to a wind turbine blade to span a gap between the blade and a spinner cover. The blade root cover segment includes a first end and a second end and comprises: a curved flange for abutting against a correspondingly curved surface of the wind turbine blade; a cover wall extending radially from the flange; and a tensioning band associated with the flange. The tensioning band comprises a first end proximate to the first end of the blade root cover segment and a second end proximate to the second end of the blade root cover segment, and wherein the first end and the second end of the tensioning band include connection means for connecting with and applying tension between a like blade root collar segment. The invention also encompasses a blade root cover comprising a plurality of blade root cover segments. The invention also extends to a method of assembling a blade root cover from a plurality of blade root cover segments.

A blade root cover segment suitable for fitting to a wind turbine blade to span a gap between the blade and a spinner cover. The blade root cover segment includes a first end and a second end and comprises: a curved flange for abutting against a correspondingly curved surface of the wind turbine blade; a cover wall extending radially from the flange; and a tensioning band associated with the flange. The tensioning band comprises a first end proximate to the first end of the blade root cover segment and a second end proximate to the second end of the blade root cover segment, and wherein the first end and the second end of the tensioning band include connection means for connecting with and applying tension between a like blade root collar segment. The invention also encompasses a blade root cover comprising a plurality of blade root cover segments. The invention also extends to a method of assembling a blade root cover from a plurality of blade root cover segments.

A method of handling the pitch bearing unit of a rotor blade mounted to the hub of a wind turbine, the method including the steps of providing an extension assembly at the interface between the rotor blade and the hub, moving the rotor blade outward from the hub by means of the extension assembly to open a gap large enough to accommodate the pitch bearing unit while maintaining a connection between the rotor blade and the hub, and removing the pitch bearing unit through the gap.

A tapered roller bearing (31a) has a plurality of retainer segments (11a, 11d) each having a pocket to house a tapered roller (34a), and arranged so as to be continuously lined with each other in a circumferential direction between an outer ring (32a) and an inner ring (33a). The retainer segment (11a, 11d) is formed of a resin containing a filler material to lower a thermal linear expansion coefficient. In addition, a clearance (39a) is provided between the first retainer segment (11a) and the last retainer segment (11d) after the plurality of retainer segments (11a, 11d) have been arranged in the circumferential direction without providing any clearance. Here a circumferential range (R) of the clearance (39a) is larger than 0.075% of a circumference of a circle passing through a center of the retainer segment (11a, 11d) and smaller than 0.12% thereof at room temperature.