Contact Traction and Creep of Lubricated Cylindrical Rolling Elements at Very High Surface Speeds

Abstract

This paper discusses test results obtained on a single contact, cylindrical, traction test machine operating at rolling speeds ranging from 5,000 fpm to 25,000 fpm and at maximum Hertz stresses from nearly zero to 200,000 psi. Effects of speed, load and contact length on traction and relative creep between two plain cylinders lubricated with a naphthenic mineral oil were investigated. Test results indicate that coefficient of traction and creep were greatly affected by all three variables tested.

Interestingly, the increase in normal load always resulted in an increase in coefficient of traction. However, beyond the contact stress of 200,000 psi, the load effect practically disappeared. No discontinuities were discovered in the coefficient of traction curves in the speed and load range tested. However, boundary lines were established separating the regions of complete hydrodynamic lubrication (where traction is nearly zero), from elasto-hydrodynamic regions (where the traction rises with load).

The obtained data paves the way for the design of traction drives capable of operating at very high speeds, such as might be encountered in gas turbine drives. Also, certain qualitative conclusions suggest several possible approaches to reducing skidding of rolling contact bearings at high speeds.

Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.

Notes

Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.