학술논문
考虑边界滑移状态的液体动静压球轴承稳定性分析 / STABILITY ANALYSIS OF SPHERICAL HYBRID SLIDING BEARINGS CONSIDERING BOUNDARY SLIP STATE
Document Type
Academic Journal
Source
机械强度 / Journal of Mechanical Strength. 46(1):176-186
Subject
Language
Chinese
ISSN
1001-9669
Abstract
液体动静压球轴承稳定性分析包括探究其动态特性及临界转速,其刚度和阻尼系数对轴承转子系统稳定性具有重要影响,而研究临界转速可有效避免轴承转子系统发生涡动失稳.考虑边界滑移条件,将小孔节流器进入油腔流量与封油边流出流量相等作为边界条件,求解出边界滑移状态下的Reynolds方程得到油腔压力和封油边压力;对边界滑移状态下瞬态Reynolds方程采用小扰动法推导出扰动压力偏微分方程,结合有限差分法和松弛迭代法求解方程得到边界滑移状态下液体动静压球轴承的刚度和阻尼系数,进而通过线性稳定性方法求解临界失稳转速,探讨滑移系数、供油压力、转子转速之于轴承动态特性的影响及临界转速之于滑移系数的变化规律.结果表明,滑移系数增大会导致 4 个刚度系数和交叉阻尼系数减小、直接阻尼增大;供油压力增大将导致 8 个动态特性系数均增大,转速增大将导致刚度增大及阻尼减小,且滑移效应的发生不影响上述规律;临界转速随滑移系数的增大而减小,系统稳定性降低.
The stability analysis of spherical hybrid sliding bearings includes exploring its dynamic characteristics and critical speed,its stiffness and damping coefficient have an important impact on the stability of the bearing-rotor system,and the study of critical speed can effectively avoid whirl instability in the bearing-rotor system.The boundary slip conditions are considered to analyze the stability of spherical hybrid sliding bearings.Taking the flow of the small hole restrictor into the oil cavity equal to the flow out of the oil sealing edge as the boundary condition,the Reynolds equation in the boundary slip state is solved to obtain the oil cavity pressure and the oil sealing edge pressure.For the transient Reynolds equation in the boundary slip state,the equation uses the small perturbation method to derive the partial differential equation of the perturbation pressure,and combines the finite difference method and the relaxation iterative method to solve the equation to obtain the stiffness and damping coefficient of the ball bearing under the state of boundary slip,and then establish the shafting trajectory equation to solve the instability speed.The influence of slip coefficient,oil supply pressure,rotor speed on the dynamic characteristics of the bearing and the variation law of the instability speed on the slip coefficient are discussed.The results show that the increase of the slip coefficient will lead to the decrease of the four stiffness coefficients and the cross damping coefficients,and the increase of the direct dampings.The increase of the oil supply pressure will lead to the increase of the eight dynamic characteristic coefficients,and the increase of the rotational speed will lead to the increase of the stiffness and the decrease of the dampings,and the occurrence of slip effect does not affect the above rules.The instability speed decreases with the increase of slip coefficient,so the system stability decreases.
The stability analysis of spherical hybrid sliding bearings includes exploring its dynamic characteristics and critical speed,its stiffness and damping coefficient have an important impact on the stability of the bearing-rotor system,and the study of critical speed can effectively avoid whirl instability in the bearing-rotor system.The boundary slip conditions are considered to analyze the stability of spherical hybrid sliding bearings.Taking the flow of the small hole restrictor into the oil cavity equal to the flow out of the oil sealing edge as the boundary condition,the Reynolds equation in the boundary slip state is solved to obtain the oil cavity pressure and the oil sealing edge pressure.For the transient Reynolds equation in the boundary slip state,the equation uses the small perturbation method to derive the partial differential equation of the perturbation pressure,and combines the finite difference method and the relaxation iterative method to solve the equation to obtain the stiffness and damping coefficient of the ball bearing under the state of boundary slip,and then establish the shafting trajectory equation to solve the instability speed.The influence of slip coefficient,oil supply pressure,rotor speed on the dynamic characteristics of the bearing and the variation law of the instability speed on the slip coefficient are discussed.The results show that the increase of the slip coefficient will lead to the decrease of the four stiffness coefficients and the cross damping coefficients,and the increase of the direct dampings.The increase of the oil supply pressure will lead to the increase of the eight dynamic characteristic coefficients,and the increase of the rotational speed will lead to the increase of the stiffness and the decrease of the dampings,and the occurrence of slip effect does not affect the above rules.The instability speed decreases with the increase of slip coefficient,so the system stability decreases.