Performance analysis of aerostatic journal micro-bearing and its application in high-speed precision micro-spindles

摘要

This study comprehensively investigates the effects of restriction, structure and operation parameters on the performance of aerostatic journal micro-bearing using modified numerical models.The numerical models are verified on a prototype aerostatic journal beating.Considering both the performance requirement and current machining capacity, the restriction parameters of 8-12 μm in average bearing clearance and 0.08-0.14 mm in orifice diameter are recommended.Another focus of this study is the aerodynamic pressure effect on the performance of micro-bearing, which is thoroughly investigated from the aspects of restriction, structure and operation parameters.The aerodynamic pressure effect is outstanding only at ultra-high speeds and large eccentricities.Two prototype high-speed precision micro-spindles are developed and their micro-tools with a diameter of 3.175 mm are directly supported by the micro-beating.The aerodynamic pressure effect resulting from ultra-high rotational speeds can improve the performance of micro-spindles under load.However, the low machining accuracy and balance quality limit their performance.