| 摘要 |
PURPOSE:To improve remarkably straight accuracy of a molded item after its outer periphery has been ground by making winding angles of a carbon fiber at least wo kinds and the each winding angle of the innermost layer and the outermost layer in a specified range. CONSTITUTION:Increase in the rigidity of a circular tube in the peripheral direction can be achieved by making peripheral winding, i.e., a fiber winding angle + or -75 deg.-90 deg.. Basic laminating angle of a cylindrical molding consists of a winding, in the direction of 0 deg.-+ or -15 deg. to ensure rigidity in the axial direction and a winding in the peripheral direction of + or -75 deg.-90 deg.. As the innermost layer of the molding, a winding of 90 deg.-+ or -75 deg. which makes Young's modulus in the peripheral direction high and a linear expansion coeff. small. The inner layer is made by a winding in the axial direction to ensure Young's modulus in the axial direction and the outermost layer is made by a winding of 0 deg.-+ or -35 deg.. It is necessary that the linear expansion coeff. in the peripheral direction of the winding angle of this outermost layer is either larger than or at least the same as the mean linear expansion coeff. in the peripheral direction of other layers except said layer to compress the internal stress of the molding. In the case of multi-layer constitution, each winding angle of the innermost and outermost layers is 90 deg.-+ or -75 deg. and 0 deg.-+ or -35 deg. respectively. |
