Abstract
This paper describes the analytical method and result of run-out of an externally pressurized air bearing based on the profile error of spindle radial direction. Bearing clearance varies due to the profile error of the spindle radial direction, and an imbalance of pressure distribution occurs on a bearing. When the whirl of the spindle occurs run-out is caused by an imbalance in pressure distribution. In this study, the Finite Element Method (FEM) is used for pressure distribution on the bearing, and run-out is calculated from the force vector balance of pressure. A ridge spindle is proposed for the analysis and the experimental model to simplify the generation mechanism of the run-out. A measuring system that measures pressure distribution has been developed to confirm the accuracy of the result obtained from the analysis of pressure distribution. The analysis result is compared with the experiment using a system with rotational precision that is similar to a roundness measuring machine. The results of this study show that the run-out is caused by an imbalance of pressure distribution with profile error of the spindle radial direction. The profile error of the spindle that affects run-out has been confirmed by the analysis and experimental results. This study shows the validity of this analysis method due to the conformity of the analysis results and the experimental results.
