Numerical and experimental analysis of rotor-bearing system for axial piston pump with misalignment–rubbing coupling fault

Abstract

Rotor-bearing system is widely utilised in axial piston pumps in which misalignment–rubbing mixed faults commonly occur, as rubbing and misalignment are both frequent and can occur simultaneously owing to the different working conditions. The dynamic behaviour of a rotor-bearing system misalignment–rubbing coupling defect supported by a ball bearing is complex. To examine the vibration characteristics of such faults, a rotor-bearing system model is established, and the dynamic responses of the rotor-bearing system with a misalignment–rubbing mixed fault are investigated under different parameters. The effects of the rotation speed, tilt misalignment, rubbing clearance, and rubbing stiffness on the rotor-bearing system with a misalignment–rubbing defect are examined via numerical simulations. Additionally, validation studies are conducted, and the results indicate that the distinctive frequency components may be useful for the detection of hybrid faults in rotor-bearing system. The degree of tilt misalignment has little influence on the rubbing frequencies. In the coupling fault, the rubbing fault is prominent. The frequency components of the system are dominated by high frequencies as the speed increases. The major fault feature in the frequency band is a double frequency. The numerical results are in agreement with the experiment. These results reveal the vibration characteristics of the rotor-bearing system for axial piston pump with misalignment-rubbing coupling fault.