Experimental research on lubrication and vibration characteristics of water-lubricated stern bearing for underwater vehicles under extreme working conditions

This paper aims at the demand of underwater vehicles for low noise, low vibration, high load capacity, and long service life water-lubricated stern bearing (WSB). A test bench was used to conduct a series of experiments to study lubrication and vibration characteristics for three test bearings with different bushing materials and structures. There are three main tests: specific pressure (0.55 MPa-0.95 MPa), environment temperature (26 degrees C-58 degrees C), flow rate (2 L/min similar to 10 L/min). Friction torque, water temperature, load capacity, and vibration acceleration signal were acquired by a torque meter, a load sensor, two thermometers, and two acceleration sensors during the test for each bearing. The experimental results indicate that the modified polyurethane bearing has the best comprehensive performance under extreme working conditions. Specific pressure and environment temperature have a significant influence on bearing performance. Under the rotational speed is 60 r/min, the growth rate of friction coefficient of modified polyamide bearing is 366.63% during the increase from 26 degrees C to 58 degrees C. The effect of flow rate on both fully grooved and partially grooved bearings is limited. Moreover, the fully grooved bearings have the characteristic of "critical specific pressure" due to the poor capacity of water film, which needs to pay more attention to bearing performance. The experimental research results provide an important reference for the material and structure design and performance test scheme of WSB.