Publicités
A chain wheel shaft is made of normalized steel C45 without heat treatment of the surface. Due to dimensional nonconformity of composing elements of wedge assembly and due to soft shaft surface, at local indenting of the edge of the gear-wheel hub keyway, a small mechanical surface damage occurred on the shaft that resulted in a crack initiation. The outcome of its slow growth, induced by rotation and rather low dynamic tensile-compressive stresses is a final break of the shaft caused by material fatigue.
Publicités