The prediction of large-scale hydrostatic bearing pad misalignment error and its compensation using compliant support

Abstract

Hydrostatic bearings offer numerous advantages in large-scale moving mechanisms and structures. Nonetheless, the limits of manufacturing, transportation, and assembly in such scales are often encountered. The manufacturing and assembly errors significantly influence the hydrostatic bearing's overall performance. Therefore, it is desirable to compensate the resulting errors and pad misalignment of the hydrostatic multi-pad bearing. Previous research dealt with accuracy improvement and error prediction of small hydrostatic guideways. A little attention was aimed at the use of compliant materials for pads, but this area did not develop any further. The present study offers a methodology on how to estimate allowed assembly errors based on the analysis of the influence of manufacturing errors on the bearing's performance. Additionally, this article describes effects of the compliant support on assembly errors of hydrostatic multi-pad bearings. The proposed prediction is compared with experimental measurements on a hydrostatic bearing experimental rig. The effects of compliant support for a hydrostatic bearing can significantly increase the allowed error as compared to the usual rigid support. Furthermore, the experimental results indicate that the prediction of performance influence based on a known manufacturing error could be used for the hydrostatic bearing's performance improvement. The obtained results might help to enhance the design process of a hydrostatic bearing and improve its performance and extend the lifetime.