Analysis On The Static And Dynamic Characteristics Of Radial-Thrust Aerostatic Bearing

Recently as the development of the precision and ultra-precision technology,people have put forward higher requirements on the characteristics of bearings. Aerostatic bearings are widely used in ultra-precision machine tools for its high accuracy, low pollution, long life and so on,and have achieved great success.In this paper,a kind of radial-thrust aerostatic bearing used in an ultra- precision machine tools has been studied.Both the static and dynamic characteristics of the aerostatic bearing has been simulated by computation fluid dynamics software.The result of the simulation is verified by comparing with the experiment result.The models of the bearing films has been established and meshed.The mesh file was then exported to Fluent.The pressure distribution and the velocity of the gas inside the film are calculated.Then the axial static characteristics and the rotational static characteristics of the aerostatic bearings are studied,the loading capacity, reverse torque, axial stiffness and angular stiffness of the bearings has been calculated. Finally, the effects of gas pressure, diameter of orifice and the number of orifice on axial static characteristics and rotational static characteristics of aerostatic bearing have been investigated,some regularity conclusions are obtained.This paper carried out experiment on the aerostatic bearing.The axial static stiffness of the bearing has been messured.The difference between simulation result and the experiment result is less than 3%,this indicte that the result of the simulation is reliable.Finally,this paper have a preliminary research on the dynamic characteristics of the aerostatic bearing.By using dynamic mesh the spindle's response to the step signal have been simulated,the change of the dynamic axial stiffness of the aerostatic bearing during the spindle's movement is obtained,the relationship between the dynamic stiffness and the static stiffness have been analyzed.