Dynamic analysis of 5-DOFs aerostatic spindles considering tilting motion with varying stiffness and damping of thrust bearings
- 4 Downloads
Aerostatic bearings are of great importance for improving machining accuracy of a workpiece surface. The dynamics of air bearings and aerostatic spindle system in ultra-precision machine, which mainly causes mid-spatial waviness errors, has a great effect on surface topography. The dynamic coefficients of the thrust bearings were determined by adopting the perturbation method and finite difference method with MATLAB® software. In addition, the influences of the spindle speed and tilt angle conducted upon the dynamics of the thrust bearings were investigated in detail. The dynamic response of the spindle system, which is closely related to the performance of the thrust bearing and does not work only by the effect of the journal bearing, supported by pressured air film was obtained. The simulation analysis of spindle responses under cutting force and experiment results is well matched, and the analysis method proposed in this paper can be also applicable to other air bearing spindle systems.
KeywordsAerostatic spindle Dynamic characteristics Dynamic model Thrust bearing Varying stiffness
Spindle speed (rad/s)
Velocity of the gas around z axis
Velocity of the gas in the β direction
Bearing clearance (m)
Restrictor inner diameter (m)
Dimensionless thickness of the gas film
Rotor mass (kg)
Gas film pressure (N/m2)
Gas supply pressure (N/m2)
Journal bearing radius (m)
Dynamic viscosity (Ns/m2)
- φx, φy
Tilt angle at steady state (rad)
Eccentricity ratio at the steady state
Unable to display preview. Download preview PDF.
This work is partially supported by the Science Challenge Project (Grant No. JCKY2016212A506-0105) and the National Natural Science Foundation of China (Grant No. 51135009).
- Y. Xu, C. An, Z. Wang, Q. Wang, Y. Peng and J. Wang, Research on surface topography in ultra-precision flycutting based on the dynamic performance of machine tool spindle, International J. of Advanced Manufacturing Technology, 87 (5-3) (2016) 1–9.Google Scholar