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针对航空发动机支承系统中各支承处滚动轴承径向游隙对整机振动响应影响的灵敏度问题,建立了含滚动轴承径向游隙的真实发动机转子-支承-机匣整机振动模型,转子与机匣采用有限元模型,支承采用集总质量模型,分别考虑了四个不同支承处的滚动轴承径向游隙和赫兹接触力的强非线性,利用数值积分方法求解耦合系统的响应,分析了整机振动响应特征。对整机振动影响较大的支承S2处,分析了不同转速下,转子、滚动轴承外圈、机匣的响应特征;分析了非线性接触力随时间-滚珠数目变化、以及滚动轴承承载变化规律;分析了该支承处径向游隙对接触力的影响。结果表明:(1)转速越高,随着间隙增大,机匣加速度振幅跳跃和滞后现象越明显,且由于滚动轴承的变刚度,当刚度变化较剧烈时,系统的固有频率被激发,即频率锁定现象;(2)在大间隙下,转速在两阶临界转速之间,转子容易出现时而挤压,时而不挤压滚动轴承外圈的现象,即不稳定现象,可以通过减小径向游隙,从而增加转子的稳定性,同时减小整机振动。
Aiming at the sensitivity problem of bearing radial clearance on the vibration response of complete machine in bearing system of aeroengine, the vibration model of a real engine rotor-bearing-receiver complete with radial clearance of rolling bearing was established. The rotor and casing The finite element model was used to support the lumped mass model. The nonlinear nonlinearities of radial clearance and Hertzian contact force of rolling bearing were considered respectively. The numerical integral method was used to solve the coupling system response. Response characteristics. The response characteristics of the rotor, the outer ring and the casing of the rolling bearing under different rotational speeds are analyzed. The variation of the nonlinear contact force with time and the number of the balls and the variation of the bearing of the rolling bearing are analyzed. The bearing radial clearance on the contact force. The results show that: (1) The higher the rotational speed, the more obvious the amplitude jump and hysteresis of the casing as the gap increases. And due to the variable stiffness of the rolling bearing, when the stiffness changes more intensely, the natural frequency of the system is excited, Lock phenomenon; (2) Under the large clearance, the speed between the two critical speeds, the rotor prone to sometimes squeeze, sometimes without squeezing the outer ring of the rolling bearing phenomenon, that is, instability, you can reduce the radial clearance , Thereby increasing the stability of the rotor, while reducing machine vibration.