Design and Analysis of Aerostatic Bearing with Restrictor
|關鍵字:||氣靜壓軸承節流器;壓電致動器;Aerostatic Bearing with Restrictor;piezoelectric actuator|
Bearing is a key element of equipments. People have already taken lots of efforts to promote the performance of bearings. According to the material between the bearing and shaft, major types of bearings include ball bearing, needle bearing, fluid bearing, air bearing, and magnetic bearing. Air bearings belong to key components in ultra-precision inspection and testing equipment, ultra-precision machining, and high-speed rotor bearings. However, they have a shortcoming of insufficient stiffness since gas viscosity is simply one thousandth of liquid viscosity. Because the advantages of air bearing itself are attractive, though it’s been developed for many years, there are still many researchers doing this kind of research, including industrial organizations and schools. But for some considerations, we often make assumptions to simplify the system of this physical phenomenon. Will these assumptions lose some important characteristics or not in the true physical system? So we use CFD software to compare the results with those derived based on those assumptions. This study uses CFD software to investigate bearing performance. We further added diaphrams to the restrictor, to investigate diaphragm effects on the air bearing. Based on the finite element method and engineering calculation, this study built fluid-structure interface models to carry out novel bearing design and calculation of loading capacity and stiffness. Controllability and observability of air bearings are derived. Eventually, using a piezo actuator controls the restrictor of the air bearing. Adding controller can make the system better according to FFT analysis results. Loading disturbance test also showed effective function of the piezoelectric actuator under a PI controller.
|Appears in Collections:||Thesis|