Patent ID: 8517671

Claim:
A wind turbine generator that generates electric power in such a manner that a rotor head that rotates when receiving wind power at wind turbine blades drives a generator installed inside a nacelle, the nacelle being installed at an upper end of a tower that is vertically erected on a foundation, the wind turbine generator comprising: a yaw driving unit that yaws the nacelle and/or a pitch driving unit that controls pitch angles of the wind turbine blades, wherein a drive mechanism of the yaw driving unit and/or the pitch driving unit, which are equipped with an engaging portion of a slewing bearing having internal teeth or external teeth and a pinion gear, is equipped with a clutch mechanism, at the engaging portion, that slides when receiving an input larger than a maximum load during driving, the clutch mechanism is configured such that a joint between a pinion gear main body and a pinion shaft of the pinion gear has a tight-fitting structure, and a sliding starting preset load is specified, and the tight-fitting structure of the joint is configured such that a shaft insertion hole in the pinion gear main body and an inserted portion of the pinion shaft are tapered surfaces, and the sliding starting preset load is specified in accordance with a compressing force of the tapered surfaces, adjusted with a bolt tightening amount.