变黏度静压滑动轴承高速时油膜动态润滑特性

静压滑动轴承转台直径大（D=4.5 m），高转速运行时产生线速度值很大，其内部润滑油膜受压及剪切发热导致油膜变薄进而影响到机床加工精度和运行可靠性。针对新型Q1-205双矩形腔静压推力轴承，采用动网格技术探索变黏度条件静压轴承高速时的油膜动态润滑特性。建立该静压轴承的流量、承载力、油膜温升等理论模型，自定义用于控制边界层网格运动及变黏度的UDF程序，选取外载荷12 t，转速为80~200 r/min（线速度18~48 m/s）高速下的工况条件参数进行动态润滑特性数值模拟，并进行相同工况参数下的试验验证，揭示出高速时油膜厚度变化对油膜温度、油腔压力、封油边处流量的影响规律。研究发现，该型号轴承在承载12 t时，随着膜厚的减小，油膜剪切发热严重，温升加剧，且高速下受润滑油黏度变化影响造成压力损失严重，研究数据为工程上静压轴承可靠运行提供理论依据。

Dynamic Lubrication Characteristics of Oil Film with Variable Viscosity Hydrostatic Sliding Bearings at High Speed

Due to the larger diameter of the hydrostatic sliding bearing turntable (D=4.5 m), so the line speed is higher at high speeds. The lubricating oil film of the hydrostatic bearing is pressed and sheared, which causes the oil film to become thinner and affects the machining precision and operational reliability of the machine tool. This research method is based on the new Q1-205 double rectangular cavity hydrostatic thrust bearing, and the dynamic mesh technology is used to explore the dynamic lubrication characteristics of oil film with variable viscosity conditional at high speed. The mathematical model of flow, bearing capacity and temperature rise of double rectangular cavity is established. The UDF program is edited for controlling the movement of boundary layer grids and variable viscosity of lubricating oil, the dynamic lubrication characteristics of hydrostatic bearings is simulated under load conditions of 12 t and the high rotational speed of 80~200 r/min that the line speed is 18~48 m/s, and the experiment verified the corresponding results under the same working condition parameters. The influence laws of oil film thickness variation on oil cavity temperature, oil cavity pressure, and flow at the sealing edge under high speed conditions are revealed. It is found that the oil films generate heat and the temperature rise increases as the film thickness decreases. The hydrostatic bearing suffers serious pressure loss due to the viscosity change of the lubricant at high speed. The research data provide theoretical basis for the reliable operation of hydrostatic bearings in engineering.