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研究了轴承内环松动的航空发动机转子系统的振动特性。结合内环间隙的轴承组件的结构和几何特点,研究轴承内环和锁紧螺母之间的相对运动关系。在此基础上提出了轴承内环和锁紧螺母之间滑动摩擦载荷的计算方法。建立了带有轴承内环间隙的竖式转子的动力学方程。该方程考虑了内环间隙带来的刚度非线性以及内环和锁紧螺母之间的摩擦载荷带来的阻尼非线性。数值求解动力学方程,得到转子系统的振动响应如波形、频谱和轴心轨迹等。定量研究转子结构参数,如转子的不平衡量、内环间隙尺寸和锁紧螺母拧紧力矩等对转子振动特性的影响。结果表明:内环端面和锁紧螺母之间的内摩擦取决于它们的相对运动关系,正比于锁紧螺母拧紧力矩,并可能促进转子同步正进动,进而导致转子失稳;转子失稳时,振动响应包含系统固有频率、工频及固有频率和工频的差频3种等频率成分;转子不平衡量、内环间隙大小和锁紧螺母拧紧力矩等均对转子的失稳产生影响;合理控制这些参数可以避免因内环松动导致的转子失稳。
The vibration characteristics of aeroengine rotor system with loose bearing inner ring are studied. Combined with the structure and geometric characteristics of the bearing assembly of the inner ring clearance, the relationship between the bearing inner ring and the locknut relative motion is studied. On this basis, the calculation method of the sliding friction load between the bearing inner ring and the lock nut is proposed. The dynamic equation of the vertical rotor with bearing inner ring clearance is established. The equation takes into account the stiffness nonlinearity caused by the clearance of the inner ring and the damping nonlinearity caused by the frictional load between the inner ring and the locknut. The kinetic equations are numerically solved to obtain the vibration response of the rotor system such as waveform, spectrum and axis locus. The rotor structure parameters such as unbalance of rotor, inner ring gap size, tightening torque of lock nut and so on are quantitatively studied. The results show that the internal friction between the end face of the inner ring and the locknut depends on their relative motion, which is proportional to the tightening torque of the locknut and may promote synchronous forward forward motion of the rotor, which leads to rotor instability. When the rotor is unstable , And the vibration response includes three kinds of frequency components such as the system natural frequency, power frequency and natural frequency, and the frequency difference of the power frequency. The unbalance of the rotor, the size of the inner ring gap and the tightening torque of the lock nut all affect the instability of the rotor. Controlling these parameters avoids rotor instability due to loosening of the inner ring.