| With the widely application of optical element of small aspherical surface,the processing methods has become important content in the field of precision machining.Precision grinding is a valid one of the main methods for realizing hard brittle materials processing.This method can significantly improve the surface quality and precision.High speed precision spindle is the core to get high precision.Air floating pneumatic spindle is very suitable for manufacturing optical element of small aspherical with the advantages of high precision and speed,small temperature rise and simple structure,and it is easy to repair.This paper designs a small kind of high-speed air-driven pneumatic precision spindle.This spindle is supported by aerostatic bearing,and driven by air turbine,which can rotate in a high speed with high pressure air drive.The main research contents includes:(1)Orifice flow controller is selected with study of aerostatic bearing design principle and the processing method,and deformation impulse turbine is also selected as driving approach.The design of whole structure is completed,including radial bearing,thrust bearing and turbine.And get the capacity of radial bearing and thrust bearing.(2)The study of bearing performance such as load-carrying ability and rigidity is studied with software Fluent.And this paper also studied the relation between load-carrying ability and eccentricity ratio,film clearance,rotation speed and orifice diameter.With the result of simulation,some theoretical calculation error is modified.(3)The spindle is also manufactured,the orifice flow controller is made quickly with new manufacturing method.Dynamitic balance adjustment is also did to get high accuracy.At last,the performance of spindle is tested,The speed achieve 50000rpm,and the radial accuracy is 0.5?m axial accuracy is 0.1 and it gets a 3N/?m of radial rigidity and 15N/?m of axial rigidity,and it also gets a good vibration with 0.2m/s~2 and noise level with 70dB(A). |
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