Patent ID: 7416199

Claim:
A steering apparatus for a vehicle, in which steering power of a steering shaft is assisted by a column-assist type electric power steering apparatus so that the steering power is transmitted to steer wheels of the vehicle by a steering mechanism, comprising: a telescopic shaft with a male shaft and a female shaft fitted to each other to be capable of transmitting torque therebetween and moving in an axial direction relative to each other, said telescopic shaft being interposed between an output shaft of said column-assist type electric power steering apparatus and an input shaft of the steering mechanism, said telescopic shaft being provided with: a first torque transmitting device including first interposing portions which are formed on an outer peripheral surface of the male shaft and an inner peripheral surface of the female shaft, first torque transmitting members which are disposed in the first interposing portions and are rotated upon relative movement of the male shaft and the female shaft in the axial direction, and elastic members which are disposed in the first interposing portions adjacent to the first torque transmitting members so as to restrain the first torque transmitting members during torque transmission between the male and female shafts and to apply preload to the male shaft and the female shaft through the first torque transmitting members when no torque is transmitted between the male and female shafts; and a second torque transmitting device including second interposing portions which are formed on the outer peripheral surface of the male shaft and on the inner peripheral surface of the female shaft, and second torque transmitting members constituted by discrete columnar bodies which are disposed in the second interposing portions, which slide upon relative movement of the male shaft and the female shaft in the axial direction, and which transmit torque during torque transmission between the male and female shafts.