Failure Analysis of Spindle Keyways and Flat Keys of a Vacuum Pump

The serious deformation failure of spindle keyways and flat keys of a vacuum pump was researched by macroscopic observation, physical and chemical performance analysis, microscopic observation and finite element force analysis. The results show that the severe compressional deformations of the spindle keyways and flat keys was mainly caused by the great impact action between the keyways and flat keys at starting and stopping instant of the pump because of the big gap between them. Besides, the hardness of the flat keys was obviously lower than that of the spindle, and the hardness difference could easily cause damage on the flat keys and make the gap between the keyways and flat keys even larger, which aggravated the deformation. Brittle cracking happened at the severe deformation positions of the keyways because of local stress concentration caused by the severe deformation.