STUDY OF THE DYNAMICS OF A PNEUMATIC SPINDLE ON CONICAL GAS-STATIC SUPPORTS WITH THE HELP OF COMPUTATIONAL EXPERIMENTS USING CAD/CAE TOOLS

Abstract

The results of a study of the dynamic stability of a pneumatic spindle on tapered gas-static bearings are presented based on determining the critical shaft rotation speeds, the amplitudes of forced vibrations and reactions in the supports, and the level of its permissible imbalance. Three-dimensional solid-state, dynamic and finite element models in CAD were developed, natural vibration frequencies and critical rotation frequencies of the pneumatic spindle were determined, the possibility of shifting the rotor natural frequencies caused by the action of centrifugal forces and the gyroscopic effect were explained. Calculations and analysis of the magnitudes of the amplitudes of forced vibrations, reactions in the pneumatic spindle supports in steady-state and transient rotation modes were carried out; it is shown that in the subcritical and postcritical regions, the trajectories of the center of masses remain symmetrical, in the critical region of the rotation speed, the amplitudes of oscillations of the spindle shaft center of masses increase, maintaining its dynamic stability and efficiency, and the increase in amplitudes at resonance does not lead to a violation of the support serviceability. The conditions under which a high-speed pneumatic spindle will retain its dynamic stability and performance in the case of simultaneous loading of the supports by both external forces and forces occurring at resonance have been determined.