气体静压止推轴承静动态性能及振动抑制

Static and Dynamic Characteristics and VibrationSuppression of Aerostatic Thrust Bearing

关键词:  轴承  静态性能  动态性能  非线性能量阱  振动

Key words:  Bearing  Static characteristics  Dynamic characteristics  Nonlinear energy sink  Virbration

摘要:

为探讨抑制气体轴承自激振动的新手段，研究了圆盘形单个小孔节流的气体静压止推轴承振动问题。通过两平行圆盘间的气体流动方程，推导建立了气体轴承静动态特性分析模型。通过数值分析的方法，研究并总结了供气压力和气膜厚度对气体轴承静态承载力、静态气体质量流量、静动态刚度以及动态阻尼的影响，计算得到了一系列气体轴承静动态特性变化曲线。然后针对系统出现负阻尼情况，通过引入非线性能量阱（NES）来抑制自激振动的问题。研究结果表明，提高供气压力可以有效地提高气体轴承的静态性能；气体轴承的自激振动主要源于气膜挤压的负阻尼特性；同时，当NES的阻尼超过临界阻尼时，可以使系统的振动得到有效的抑制。

Abstract:

To investigate a new method to suppress the self-excited vibration of gas bearing, the vibration of the disk aerostatic thrust bearing with single orifice compensation was studied. Based on the gas flow equation between two parallel discs, the static and dynamic characteristics analysis models of gas bearing were established. By method of numerical analysis, the effects of gas supply pressure and film thickness were studied and summarized, which included static capacity, static gas mass flow rate, static and dynamic stiffness and dynamic damping of air bearing. By calculating, a series of curves of static and dynamic characteristics of air bearing are obtained. A nonlinear energy sink (NES) was introduced to deal with the self-excited vibration of bearing system which caused by negative damping. The results show that the static characteristic of gas bearings can be effectively improved by increasing the supply pressure. The self-excited vibration of gas bearings is mainly due to the negative damping characteristics of gas squeezing. And the vibration of the system can be effectively suppressed when the damping of NES exceeds the critical damping.