精密铣磨床旋转工作台静压轴承的设计和试验研究

Design and Experimental Study of Hydrostatic Bearing for Rotary Table of Precision Milling and Grinding Machine

旋转工作台是数控机床的重要组成部分,其运行精度直接影响被加工件的形面误差和表面粗糙度。从精密数控铣磨床旋转工作台支撑轴承的设计出发,选用静压轴承支撑形式并对轴承进行设计及试验分析。设计的径向轴承和推力轴承分别为4油腔和8油腔带回油槽结构,节流方式选择小孔节流。计算轴承油膜刚度随半径间隙和节流孔径的变化,根据计算结果确定半径间隙和节流孔径的大小。在模拟测试装置上对设计轴承的回转精度进行测试,测试指标为径向跳动和轴向窜动,测试结果表明径向跳动最大0.15μm、轴向窜动最大0.1μm,设计的轴承满足精密转台的使用要求。

Rotating table is an important part of CNC machine tools, and its operation accuracy directly affects the shape error and surface roughness of the workpiece.Starting from the design of the support bearing of the rotary table of the precision CNC milling and grinding machine, the static pressure bearing support form was selected and the bearing was designed and tested.The radial bearing and thrust bearing were designed with 4 oil chambers and 8 oil chambers with oil return groove structure respectively, and small hole throttle was selected for the throttling method.The changes of bearing oil film stiffness with radius clearance and throttle aperture were calculated, and the sizes of radius clearance and throttle aperture were determined according to the calculation results.The rotation accuracy of the designed bearing was tested on a simulation test device.The test indicators were radial runout and axial channeling.The test results show that the maximum radial runout is 0.15 μm and the axial channeling is 0.1 μm.The designed bearing meets requirements for the use of precision turntables.