3-D surface analysis of worn spherical roller thrust bearings

Abstract

Wear of boundary lubricated spherical roller thrust bearings has been characterised with 3-D surface measurements and analysis. Due to the curved contact surface in a spherical roller thrust bearing, the rollers will undergo sliding in the contact. For an unskewed roller there will be two points along each contact where the sliding velocity is zero. At all other points along the contact, sliding is present. Previously presented results from measurements of the contacting surfaces show that outside the zero sliding points there is a significant change in the washer surface profile due to wear. In order to study how the wear depends on the number of revolutions ten tests were performed. After the tests, 3-D surface roughness measurements were performed. The results from these measurements show that there are different wear mechanisms involved. Initially, the surfaces are run in by possible plastic deformation and two-body abrasion. After running-in, the surfaces are subjected to mild wear probably caused by two-body abrasion and/or delanunation wear. For the long term tests, three-body abrasion clearly influences the amount of wear. A 3-D parameter set was used to characterise the different wear mechanisms. Three amplitude parameters (S a, S q S z) and three of the functional Abbot curve parameters (S pk, S k, S vk) were able to characterise all the wear mechanisms.