加速度对涡轮增压器球轴承-转子系统动力学特性的影响

Influences of acceleration on dynamic characteristics of a turbocharger's ball bearing-rotor system

车用涡轮增压器转子系统具有高速、轻载荷、大柔性、小尺寸、多激励、变工况特点,球轴承涡轮增压器轴承-转子系统转速会在较大范围内频繁变动。针对某型号车用球轴承涡轮增压器,建立考虑了密封结构和气流激振的球轴承涡轮增压器转子动力学模型,分析了不同加(减)速度下的球轴承涡轮增压器转子瞬态响应规律,并与该转子系统临界转速、稳态响应及临界转速实验结果进行对比分析,结果表明:球轴承涡轮增压器一阶临界转速随加(减)速度增大而减小,二阶临界转速随加(减)速度增大而增大;加(减)速下的球轴承涡轮增压器转子振幅在临界转速附近随加(减)速度增大而增大,非临界转速范围内变化不大。

A vehicular turbocharger＇s rotor system has features of high speed,light load,large flexibility,small size,multi-excitation and varying operation condition,so its rotating speed can frequently vary within a wider range.Aiming at a certain type of vehicular turbocharger,a rotor dynamic model of a vehicular turbocharger considering seal structures and gas flow-exciting was established.The influences of acceleration on the transient responses of the the bearing-rotor system were analyzed.The results were compared with those of numerical calculation and test for critical speeds and steady-state responses of the rotor system.The comparison results showed that the first order critical speed of the system decreases with increase in accelevation or deceleration or decaleration,but the verying of its second order critical speed is contrary; the amplitudes of the transient vibrations of the rotor increase with increase in acceleration or deceleration within the speed ranges near the critical speeds of the system,but they vary little in other speed ranges.