Analysis of High-Speed Intershaft Cylindrical Roller Bearing with Flexible Rings

For high-precision mechanisms such as machine tools or gas-turbine engines, which operate at extreme conditions, it is particularly important to accurately predict the behavior of the included bearing. This prediction includes, among other things, its load distribution, stiffness, and power dissipation. Although shaft speeds tend to increase, rings and shaft walls are becoming thinner due to size and weight constraints. Thus, bearing behavior is no longer independent of the housing and ring stiffness. This paper focuses on the problem of elastic ring deformation and certain behaviors of high-speed intershaft cylindrical roller bearings such as heat dissipation, contact pressure, and risk of bearing failure due to scuffing. The paper presents an analytical method to account for the structural deformation of the rings based on Roark's formulas. The elastic deformation of thin cylindrical rings has been introduced in the set of displacement and load equations that describes the bearing equilibrium. A correlation with a high-speed intershaft cylindrical roller bearing application is made and the results are compared with those obtained with the finite element method for housing deformations. Heat dissipation, load distribution, contact pressure, and internal kinematics are discussed to evaluate co-rotating and contrarotating shaft design solutions.

KEYWORDS:

• Flexible Ring
• Housing Deformation
• Power Loss
• Roller Bearing
• High Speed
• Scuffing
• Skidding
• Skid-Mark Damage

ACKNOWLEDGMENTS

The authors are indebted to Daniel Baïnachi from SNECMA for performing the FEM analyses.

Presented at the 58th STLE Annual Meeting

in New York City, New York

April 28 to May 1, 2003

Manuscript approved November 4, 2004

Review led by William Crecelius