球轴承刚度对涡轮增压器瞬态响应的影响

Influences of ball bearing stiffness on transient response of a turbocharger

在载荷的作用下,角接触球轴承的接触角会产生变化,从而影响轴承支撑刚度。针对某型号车用混合陶瓷球轴承涡轮增压器,建立考虑密封结构及叶顶间隙气流激振的涡轮增压器混合陶瓷球轴承-转子系统动力学模型,在加速和减速两种工作状态下,分析考虑轴承载荷作用时转子系统的瞬态响应规律。结果表明:轴承载荷作用使轴承支撑刚度减小时,压气机质心振幅变化小且有增有减,涡轮质心振幅均增加。在涡轮增压器混合陶瓷球轴承-转子系统设计参数许可范围内,轴承载荷变化使接触角变化、轴承刚度变化,导致涡轮增压器瞬态响应振幅的变化较小。

Under the action of loads,the contact angle of an angular contact ball bearing can be changed,and then affect the bearing support stiffness. For a certain type of vehicle turbocharger with hybrid ceramic ball bearings,a turbocharger ball bearing-rotor dynamic system model considering seal structures and tip clearance gas excitation was established. Under acceleration and deceleration two working conditions,the turbocharger＇s rotor transient response law was analyzed considering bearing loads. The results showed that when bearing loads make the stiffness of the bearing support be reduced,the variation of the compressor centroid＇s is small and it increases or decreases,while the amplitude of the turbine centroid increases; if design parameters of the turbocharger-hybrid ceramic ball bearing-rotor system are in the permitted ranges,the change of the transient response amplitude of the turbocharger is smaller due to bearing load changes and then changes in contact angle and bearing stiffness.