CAGEDYN: A Contribution to Roller Bearing Dynamic Calculations Part I: Basic Tribology Concepts

Abstract

Basic relationships and physical concepts used for the development of a bearing dynamic tool (called CAGEDYN) are explained. Emphasis is put on some key physical concepts affecting the calculated cage impact forces: the appropriate roller-cage contact stiffness (derived herein using a novel equivalent stiffness), the tangential hydrodynamic rolling and pressure forces, the hydrodynamic effect on the roller normal load (for which a new relationship is given for calculating a load, even when there is no interference between the roller surface and counter race or cage bridge surface), and the appropriate traction force calculated using a nonlinear viscous model and contact temperature increases.

KEY WORDS:

• Rolling Bearings
• EHL
• Traction
• Rolling Friction
• Dynamic Impact Forces
• Cage Stiffness

ACKNOWLEDGMENTS

The author would like to thank the TIMKEN Company for permission to publish this work, as well as several interns (F. Constantin, N. Koenig, and T. Favre especially) who started IMPACT6 and CAGEDYN and some colleagues (J. Suchanek, D. Prock, M. Cadile, E. Hood, and P. Roy) who took part in the development of CAGEDYN or benchmarked it versus some application field results. Special thanks also to B. Pederson for his contribution to DBM and our discussions about cage calculations.

Review led by Bob Bruce