Shaft connection structure

Abstract

A tightened shaft portionof a shaftand a tightened portionof a lower joint yokeare coupled with each other such that a required torque can be transmitted therebetween by inserting the tightened shaft portionof the shaftinto a shaft insertion holeof the lower joint yoke (a coupling member), and inserting a boltinto a bolt insertion apertureof the lower joint yokeand a bolt engagement grooveof the shaftand tightening the bolt in the condition (the regular position condition) that the bolt engagement grooveof the shaftand the bolt insertion apertureof the lower joint yokeare axially aligned with each other. An insertion restriction portionhaving a diameter smaller than that of the tightened shaft portionis provided at the tip end of the tightened shaft portionof the shaftfor restricting the insertion of the boltthrough the bolt insertion apertureof the lower joint yokein the condition (the non-regular position condition) that the insertion restriction portionaxially overlaps the bolt insertion apertureof the lower joint yokewhen the tightened shaft portionis inserted into the shaft insertion holeof the lower joint yoke, and the insertion restriction portioncan be rotated relative to the shaftby a set torque smaller than the required torque.