Tapered hollow shaft

Abstract

A tapered hollow shaft made of a fiber reinforced composite material, which comprises: (a) at least one angle layer consisting essentially of polyacrylonitrile-based carbon fibers having a tensile modulus ranging from 200 to 500 GPa and a tensile strength ranging from 4000 to 5600 MPa; (b) at least one straight layer consisting essentially of polyacrylonitrile-based carbon fibers having a tensile modulus ranging from 200 to 460 GPa and a tensile strength ranging from 3500 to 5600 MPa; (c) at least one reinforcing layer consisting essentially of pitch-based carbon fibers or polyacrylonitrile-based carbon fibers each having a compressive breaking strain of 1.7 to 5.0%, a tensile modulus ranging from 5 to 160 GPa, a tensile strength ranging from 500 to 3000 MPa and a density ranging from 1.5 to 1.9 g/cm3 with the carbon fibers in the reinforcing layer being oriented to incline at an angle of 0° to ±5° to the axial direction of the shaft, with the reinforcing layer being arranged at the thinner portion of the shaft to extend from a tip thereof up to at least {fraction (1/20)} and not more than ¾ of the entire length of the shaft, and with the reinforcing layer being arranged at the outermost portion of the shaft.

Dependencies are inferred from the claim text.