Transient Lubrication Monitoring of Journal Bearing Via Novel On-Rotor Sensing Technology

Transient lubrication monitoring of journal bearings is important to assess journal wear and maintain healthy operation of journal bearing rotor systems. The conventional vibration measurement technique is constrained in its ability to accurate sense the dynamic response induced by microscopic random excitation in the journal bearing system due to signal transmission path and system noise. Hence it is difficult to identify the transient lubrication condition of journal bearing. In this paper, a new measurement strategy is proposed to directly sense the dynamic response of the rotating shaft that journal bearing supports, via an On-Rotor Sensing (ORS) accelerometer embedded into the end of the shaft. The acquired time-varying vibration signals are represented in the timefrequency domain by a transient power spectral density (TPSD) method. Experimental results show that the higher-order modal responses of journal bearings can have a Stribeck curve-like tendency, hence fully verifying that ORS technology enables the monitoring of transient lubrication of journal bearings.