Blade For Vertical Axis Wind Turbine and Lift Type Vertical Axis Wind Turbine Having the Same

摘要

A blade for a vertical axis wind turbine and a lift type vertical axis wind turbine having the blade are provided to easily suppress excessive increase of the rotation rate of the wind turbine with a simple mechanical structure when increasing the rotation rate of the wind turbine to a prescribed value or more. The blade has an air brake and a shaft bearing disposed at a position nearer the rear edge with respect to the gravity center of the air brake. The air brake is mounted rotatably on the blade through the shaft bearing. Inside the front portion of the air brake, a substantially S-shaped spring backing plate is mounted. The spring backing plate largely protrudes frontward out of the air brake and urged by spring members serving as a protrusion forbidding member disposed nearer the front portion of the windsail chamber. When increasing the rotation rate over a prescribed value, the front edge of the air brake protrudes out of the wing surface by a centrifugal force while the rear edge of the air brake retracts inward from the wing surface, thus to produce air resistance, resulting in suppressing increase of the rotation rate of the wind turbine.