Effects of controlled vibration induced gapping on the torque performance of lubricated ball bearings

Sochting, Sven (2003) Effects of controlled vibration induced gapping on the torque performance of lubricated ball bearings. Masters thesis, University of Central Lancashire.

[thumbnail of Thesis document] PDF (Thesis document) - Submitted Version
Restricted to Repository staff only
Available under License Creative Commons Attribution Non-commercial Share Alike.



Ball bearings that are not sufficiently preloaded may be subjected to gapping and transient high contact stresses during launch. Despite the fact that such phenomena may cause bearing damage or degrade torque performance and lubricant life, the dynamic behaviour of bearings subjected to typical launch vibration has been little studied. Given this, it is clearly of interest to understand how exposure to the launch vibration impacts upon bearing and lubricant performance.
This thesis outlines a study concerned with an experimental investigation to improve the current understanding of the influence of vibration effects on the torque performance of solid and liquid lubricated angular contact bearings.
The work employed a apparatus to evaluate relative bearing ring displacements by means of two laser triangulation transducers as well as a apparatus to measure the resulting impact on the bearing torque behaviour. The investigation was performed on hard-preloaded SEA 65 type bearing pairs, which were lubricated with both; Braycote 601 EF grease and ion plated led. In addition a simplified analytical model was developed to predict gapping for the used test fixture at a range of different test conditions is presented. The comparison between analytical and experimental values revealed a reasonable level of agreement. This thesis presents photographic of the observations of bearing damage resulting. Visible indentations were caused at mean gapping level of around 20p.m, which are believed to result from a single ball raceway
contact with an equivalent static load in excess of 4500 N.
The observed, vibration related, increase of mean torque and torque noise on the lead lubricated bearings decreased considerably after the bearings were extensively run.
There was little change in terms of mean torque and torque noise as a result of the grease lubricated bearings despite the severe damage observed after they had been subjected to 40-50im gapping.
A program of further experimental work is outlined to validate and further develop the simplified gapping and bearing damage models.

Repository Staff Only: item control page