Intermediate steering shaft

摘要

An intermediate steering shaft for a motor vehicle steering system including a tabular outer shaft, a tubular center shaft slidably telescoped in the outer shaft, and a solid inner shaft slidably telescoped in the center shaft and all coupled for unitary rotation by respective pairs of flat sides on each. Each of the flat sides of the tubular center shaft is interrupted by a pair of outward facing shallow grooves always concealed in the overlap between the tubular outer and center shafts. One of the flat sides in the tubular center shaft is further interrupted by an exposed shallow groove located near a distal end of the outer shaft in an extended or normal position of the tubular center shaft. A plastic end fitting is in situ injection molded on the tubular outer shaft and includes a pair of thin, flat slide bearings in the concealed shallow grooves, a plurality of shear pins in the inlet and discharge passages, and a collar around the distal end of the outer shaft and an adjacent portion of the center shaft. If the shear pins are fractured inadvertently, a lip of the collar engages an edge of the exposed shallow groove to obstruct telescoping of the tubular center shaft into the tubular outer shaft.