Study of sensitivity and interference protection of various bearing diagnostics methods

Abstract

Due to the widespread use of bearing units with rolling bearings in ship equipment, the question of using diagnostics-in-place methods to determine their technical condition is relevant. For diagnostics, various methods of different sensitivity and interference protection can be applied. These qualities are of particular importance for diagnosing the bearing units of ship’s gearboxes access to which can be difficult, and the units themselves include several different types of bearings. The article provides materials on comparing the sensitivity and reliability of two methods for diagnosing rolling bearings: the diagnostic method based on the analysis of the envelope spectrum and diagnostic method based on shock pulses. Measurements were taken by these methods at different points of the bearing unit on the special bench, equipped with two different bearings. Previously, defects on the ring were artificially created on one of the bearings of the unit. Measurements have shown that the shock pulse method provides acceptable results only when a sensor is located directly at the point adjacent to the outer ring of the bearing. At the control points distant from the bearing location, the defect was diagnosed with an error, but the presence of a defect, nevertheless, could be determined by applying monitoring at a specific point of control. The method of analyzing the envelope allows secure detecting and identifying the defect even when a sensor is installed at a considerable distance from the bearing. The influence of the interference generated by the mounted lubrication pump is considered. The envelope spectra and the nature of their changes are provided.