Title

EFFECTS OF TEST CONDITIONS ON BEARING PERFORMANCE

EFFECTS OF TEST CONDITIONS ON BEARING PERFORMANCE

Authorship

Kernizan, Carl F.; Groote, Carlos L. Cerda de; Bartlett, Melinda E.

DOI

10.5151/2594-5327-0353

Downloads

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Abstract

This work explains the effects of test conditions on the performance of grease lubricated tapered bearings. The elastic modulus (G’) of two NLGI 2 grade greases, A and B, was measured at temperatures from 25 to 150°C using a rotary viscometer. G’ was consistently higher in B indicating that it was stiffer and more shear stable than A. All test conditions were generated with a KRL rig and were designed to simulate various lubrication regimes described by the Stribeck-Hersey curve. Six test sequences with specific speed and load combinations were implemented at four grease loadings and two operating times. In each sequence, bearing performance was evaluated by measured torques and temperatures and by completion of the operating time. The starved flow lubricant model in combination with the rheological data was used to describe grease behavior and assign the corresponding lubrication regime during each sequence. The tribological data indicates that both greases performed equally well in low to medium severity sequences. In the more severe sequences, all failures were temperature related and superior tribological performance was linked to the higher stiffness and greater shear stability of grease B.

 

This work explains the effects of test conditions on the performance of grease lubricated tapered bearings. The elastic modulus (G’) of two NLGI 2 grade greases, A and B, was measured at temperatures from 25 to 150°C using a rotary viscometer. G’ was consistently higher in B indicating that it was stiffer and more shear stable than A. All test conditions were generated with a KRL rig and were designed to simulate various lubrication regimes described by the Stribeck-Hersey curve. Six test sequences with specific speed and load combinations were implemented at four grease loadings and two operating times. In each sequence, bearing performance was evaluated by measured torques and temperatures and by completion of the operating time. The starved flow lubricant model in combination with the rheological data was used to describe grease behavior and assign the corresponding lubrication regime during each sequence. The tribological data indicates that both greases performed equally well in low to medium severity sequences. In the more severe sequences, all failures were temperature related and superior tribological performance was linked to the higher stiffness and greater shear stability of grease B.

Keywords

Grease; Rheology; Tribology.

Grease; Rheology; Tribology.