可压缩静压支撑抗偏载动态特性分析与优化

Load-Deflection Resistance Dynamic Characteristic Analysis and Structure Improve of Compressible Hydrostatic Bearing

摘要:

火箭推力矢量控制系统采用静压支撑技术获得抗偏载、低摩擦等优异性能，但极高温度和大温差工作环境形成支撑结构局部介质的高含气量强可压缩流动，导致活塞杆振荡超调，过大偏心距导致油膜承载失效.在进行推力系统矢量分析基础上，获得静压支撑作动的边界条件与介质参数，基于油缸动力学建模与局部线性化求解，获得了静压支撑动态特性的一般规律.研究表明，增加供油压力可提升支撑能力，但易导致响应超调；采用合理的油腔深度可在保持承载力基础上避免超调的发生；进一步将油腔结构改为锥形，可在保持支撑能力和避免超调前提下进一步减少泄漏损失.

Abstract:

It was supposed to employ hydrostatic bearing technology for rocket thrust vector control system, to bring its loaddeflection resistance and low friction merits. However, the rockets always worked in serious conditions with much higher and largerspan temperatures, causing the hydrostatic bearing full of gas and much compressible, which contributed to the piston rod response overshoot and vibration. If the overshoot was too large, the oil slick will broke and lost its radial force holding feature. The present paper work modeled the piston rod dynamic motions and obtained the system transfer function with equation partlinearization, to conduct a detailed investigation of hydrostatic bearing dynamic behavior. It was found that, higher oilsupply pressure assures higher radial force holding ability, but meanwhile the overshoot response would be more likely to occur. Reasonable bearing cavity depth would prevent the response overshoot and maintain the force holding ability. Moreover, a cone shape design of bearing cavity would reduce the leakage.