| 摘要 |
PROBLEM TO BE SOLVED: To solve problems that it is impossible to thin the blade made of a lightweight material of low rigidity, such as a fiber-glass reinforced plastic or the like used as a material of the blade of a large windmill, which causes the noise by the vortex produced near a tip part of an outer periphery of a blade, particularly at a high speed, and the flattering phenomenon, the vibrational fault and the impairing of the performance by the deflection and torsion of the blade. SOLUTION: The tip part of the outer periphery of the blade is made of a metallic material having high elastic modulus and high specific gravity such as stainless steel, and connected to a blade mounting member at a hub side by means of a tension rod of lightweight and high strength such as carbon fiber. By applying this constitution, a thickness of the tip part of the outer periphery of the blade can be remarkably reduced, whereby not only the noise caused by the vortex can be reduced, but also the deflection and the torsion of the blade can be recovered as the blade is radially pulled by the weight effect (centrifugal force) of the metallic material, and the flattering phenomenon, the vibrational fault or the like caused by the turbulence of the wind can be prevented effectively. |
