Pivot Fatigue

Vibration can cause fatigue damage of tilt pad pivots, as well as the carrier ring or housing, by indentation or fretting. In some cases, tiny cavities of almost hemispherical form may be produced.

In the case of thrust bearings, damage may occur due to axial vibration imposed upon the shaft, or may be caused by the thrust collar face running out of true (swash). If signs of fretting are also present on the bearing surface, the cause is more likely to be static fretting.

Addressing the Damage

Recondition the pad housing or carrier ring, and fit new or reconditioned pads.

To prevent future damage, investigate the cause of the vibration, with the purpose of eliminating or mitigating the vibration. Changing to a fixed profile bearing design may also be considered in applications where a rotating load is unavoidable.

Figure 1: Pad carrier ring showing damage due to axial shaft vibrations