精密数控机床闭式静压导轨结构设计及油腔流场研究

Structural Design and Research on Oil Chamber Flow Field for Closed Hydrostatic Guideway of Precision CNC Machine

针对精密数控机床对导轨精度的要求,设计一种基于薄膜反馈节流器的闭式静压导轨系统,并根据无穷大刚度原则计算了导轨的结构参数。利用三维软件SolidWorks建立静压导轨油腔的三维模型,导入流体力学软件FLUENT的前处理器Gambit进行网格划分;在设定一定进口压力条件下,给定导轨在静止状态和移动状态下的静压腔流场与温度场的变化规律。通过FLUENT的数值分析得到:在相对静止状态下,静压腔的流场成对称分布;相对速度变大时,静压腔流场在边缘区域压力成不规则的下降,温度在此区域急剧上升,容易出现"气穴"现象,致使油液发热,从而导致导轨运动精度降低。

To fulfill the accuracy requirement of precision NC machine tools,a kind of closed hydrostatic guideway system was designed based on thin film feedback throttler,and the structural parameters of the guideway were calculated according to the infinite stiffness principle.Three-dimensional software SolidWorks and Gambit were used to establish oil chamber model of hydrostatic guide-way and generate mesh respectively.Under the same inlet pressure,the distribution laws of flow field in static pressure chamber and temperature field were obtained respectively during the guideway stopping and moving.It is concluded that,the distribution of flow field in static pressure chamber is symmetrical,and when relative velocity increases,the pressure near edge zone of flow field in static pres-sure chamber decreases unregularly,and the temperature of the zone rises increasingly,which will cause cavitation,oil emitting heat and the kinematic accuracy of guideway reducing.