Extendable shaft for steering vehicle and motor vehicle steering system

摘要

An extendable shaft for steering vehicle rotated according to the steering of a steering member comprises: an inner shaft and a tubular outer shaft fitted with each other in a manner to be capable of relative sliding movement; a rigid coupling element for rigidly interconnecting the inner shaft and the outer shaft in a circumferential direction of the inner shaft when a relative phase of the inner shaft and the outer shaft with respect to the circumferential direction exceeds a predetermined range; at least three pairs of axial grooves individually formed on an outer periphery of the inner shaft and an inner periphery of the outer shaft and opposed to each other; and a plurality of elongate resin rods as elastic coupling elements for elastically interconnecting the inner shaft and the outer shaft in the circumferential direction when the relative phase thereof is in the predetermined range. Each of the plural resin rods is interposed between the mutually corresponding axial grooves. At least one of the resin rods has a different specification from that of the other resin rods in order that an axis of the inner shaft and an axis of the outer shaft are tilted to each other.