| 摘要 |
PURPOSE:To obtain a wind mill blade, prevented from easily causing a trouble and also easily manufactured inexpensively with no complicated device of variable pitch mechanism or the like required, by forming the blade, made into a laminated structure, partly into the laminated structure having at least one layer of asymmetrical orientation angle. CONSTITUTION:A wind mill blade 2, requiring strength, rigidity and lightness against wind force, is formed of a plurality of layers of fiber reinforced compound material. Normally the more required are the rigidity and the strength, the larger a number of layers of this fiber reinforced compound material is increased. Accordingly, normally the number of laminated layers in a base part 2a is increased larger than that in a point end part 2b, of the wind mill blade 2. A fiber orientation angle of the layer is given symmetrical orientation of + or -theta with theta=0 as the main orientation in order to increase strength and rigidity and further to ensure the symmetry of deformation. Here the point end part 2b is partly molded by laminating the layer of asymmetrical orientation. That is, of the plurality of layers of fiber reinforced compound material 2c, a single or plurality of layers of fiber reinforced compound material 2c on a surface part are formed by laminating the layer so as to provide the orientation angle thetaat 10 deg. through 50 deg. and further the asymmetrical orientation. |
