Patent ID: 8212372

Claim:
A wind turbine generator, comprising: a rotor head that has wind turbine blades, wherein the rotor head rotates, when the wind turbine blades receive wind power, and drives a power generator disposed in a nacelle to generate electricity, the nacelle is disposed on an upper end of a tower that stands on a foundation such that the nacelle can yaw-slew, a blade rotating ring bearing that is disposed between the wind turbine blade and a rotor, wherein the wind turbine generator includes a pitch control mechanism to adjust a pitch angle of the wind turbine blades, seal mechanisms are mounted on both ends of opposed rolling body holding surfaces of an outer race and an inner race of the blade rotating ring bearing with rolling bodies interposed between both the ends, and sides of the seal mechanisms that are closer to the blades and are formed into a double sealed structure in which a space is provided between seal members and the seal members are disposed in an axial direction of the blades, wherein pressurized fluid is adapted to be supplied to the space, and lips of the seal members are pushed against a mating sidewall surface.