Analysis And Simulation On Loading Characteristics Of Precision Aerostatic Bearing

The precision requirement is higher and higher in the modern production, and it has greatly promoted the development of the test, optics-mechatronics, and precision machining technology. As the main actuator of the rotation measurement that can measure the large-aperture aspheric surfaces, the precision aerostatic turntable has such advantages as higher precision, lower friction and non-pollution. As the main supporting part, the plane aerostatic thrust bearing can bear the weight of the entire areostatic turntable and related equipment, thus increasing the loading capacity of aerostatic bearing has become an important part of the aerostatic lubrication theory research and aerostatic bearing design.The aerostatic lubrication thrust bearings of the biaxial flotation turning used to precision rotation measurement are mainly studied in this paper. The control equation of orifice compensated static pressure thrust bearing is established based on the theory of aerostatic lubrication and the method of Computational Fluid Dynamics, and the control equation is discretized using the second-order upwind format of finite volume method. The geometry and grid model of the annular hydrostatic thrust bearing are created, and the boundary conditions such as inlet pressure, outlet pressure and wall are set. FLUENT software is used to optimize the structure of the bearing, and the indicators of bearing characteristics are obtained under different structures. The calculation results show:under the single structure with circular recess, when the radius of orifice distribute circle is about 55mm, the gas consumption is lowest, and it can meet the equal conditions of internal and external flow, when the radius of orifice distribute circle is about 65mm, the static loading capacity is largest, the power consumption per unit of load is the lowest. For single-row air supply, static loading capacity under the form of 30° uniformly arranged is largest, the gas consumption and power consumption per unit of load under the form of 60° non-uniformly arranged is the lowest. Under the structure of the single pressure-equalizing groove:interlaced distribution is better than sequential distribution in the double-rows air supply, under the conditions of the gas film less than 22μm, the static loading capacity and static stiffness provided by the double pressure-equalizing grooves are larger than the single row pressure-equalizing groove, and the power consumption per unit of load in the single row pressure-equalizing groove is smaller than the double-rows. In order to improve the loading capacity of aerostatic bearing, the double-rows connected type pressure-equalizing groove is better.Through the analysis of the simulation results, based on the guarantee of the test system’s stability, a structural form of the aerostatic bearing is proposed When the static loading capacity and static stiffness is maximum, and this structure can meet the loading requirements of the biaxial flotation turntable, which has a certain significance on design and simulation of the static pressure thrust bearing.