Advanced bearing analysis of a planetary spherical roller bearing from a helicopter

David Scott, Principal engineer – Gearboxes and Aerospace, Romax Technology

Thursday 15th November

9:00-10:00 / 16:00-17:00

This advanced bearing analysis was performed as part of an investigation into a catastrophic failure of a helicopter main gearbox planet bearing.  Two different bearing designs existed – the aim of the Romax analysis was to ascertain whether there were differences between them which would affect their life.  The analysis specifically focused on the bearing and used many of the advanced capabilities of the RomaxDESIGNER software including: –

  • Precise modelling of internal bearing micro geometry
  • Flexible bearing races (Finite element)
  • Gear deflection effects on the integrated outer race
  • Analysis of rolling element load distribution and roller contact analysis
  • Bearing rating to ISO TS 16281 incorporating all of these effects.


  • Although the bearings are nominally the same, there are significant internal differences in geometry
  • The resultant contact stress distribution drastically affected the bearing life

Who should attend?

Engineers, Bearing analysts, design engineers, bearing suppliers, bearing experts