Drive vehicles bearing the framework by the torsion stress in the work of fracture sites in the spline.By macro-and micro-fracture analysis and detection of low-fold-etching results showed that:With the forging of post-dense rough machining out a good organization,and the main force Department metallurgical defects,such as the existence of osteoporosis reduces the density of steel.Mm Φ2 gear on the hole reduces the effective tooth spline cut-off area set to become the framework of stress concentration leading to the fracture axis.
Key words:osteoporosis spline hole low-cycle fatigue