Field case · Condition monitoring
Roughing mill gearbox: four vibration findings that traced back to a fretted bearing fit
Quick answer
A roughing mill gearbox had a short pinion life and alignment that never held. Four findings, misalignment, pinion damage, second-stage gear damage and bearing fretting, were put together into one sequence that began at a loose bearing fit.
What the case covers
- The gearbox
- Finding 1: parallel misalignment at the motor and gearbox and angular misalignment at the gearbox
- Finding 2: pinion damage
- Finding 3: second-stage gear damage
- Finding 4: fretting in bearing 4
- The interpreted sequence
- What to take from it
Takeaway. When alignment will not hold, check the bearing fit. Looseness in one place travelled through the whole gear train.
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