电磁轴承支承的柔性转子在轴承失效后坠落过程中的瞬态响应

研究了主动电磁轴承支承的单盘柔性转子系统在磁轴承失效后转子坠落在带有固定间隙的滚动型备用轴承上的瞬态响应,分析了备用轴承的各种参数对瞬态响应的影响。结果发现系统出现了以自由落体-碰撞弹起-自由落体为特征的在间隙圆底部的摆动运动、以碰撞弹起-加速落体-碰撞弹起为特征的在整个间隙圆范围的碰撞型回转运动以及轴颈与备用轴承始终接触在一起的摩擦型回转运动等3种运动形式。碰撞型回转运动实际上是由碰撞过程中部分周向的摩碰引起,而摩擦型回转运动是由轴颈与备用轴承之间的全周干摩擦所致。碰撞型回转运动和反向摩擦型回转运动对备用轴承的影响最为严重。

Transient Response of Rotor Drop on a Rolling Element Backup Bearing in a Flexible Rotor Supported on Active Magnetic Bearings

Transient response of rotor dropping on a rolling element backup bearing with a fixed radial clearance in a flexible rotor supported on active magnetic bearings after active magnetic bearings failure is theoretically analyzed, the effects of the rolling element backup bearing’s parameters, such as support damping, support stiffness, radial clearance of the backup bearing and impact stiffness, on the transient response are dealt with. It is found that there exist three different types of motions during rotor drop, which are oscillation motion back and forth with bounces in the bottom half of the clearance circle, full clearance whirl motion with impact and full clearance whirl motion without impact. The full clearance whirl motions has a great effect on the reliability of the backup bearings. The full clearance whirl motion with impact is caused by the partial annular dry friction during impact between the journal and the inner race of the rolling element backup bearing, but the full clearance whirl motion without impact is produced by full annular rubbing between the journal and the inner race of the rolling element backup bearing. There is an optimal region of support damping for suppressing the full clearance whirl motion, which depends on the rotational speed and other parameters.