Review of the Vibration Isolation Technology of Submarine Thrust Bearing

The mechanical noise at submarine stern has always been the research emphasis in vibration control and noise reduction, and large power plant at the stern is the main noise source. When the vibration of power equipment is controlled well, the thrust bearing at the stern will become the main factor affecting submarine noise. Based on the noise test results of submarines which have put into practice currently, it can be found that the radiation noise caused by the vibration of submarine thrust bearing is very prominent, and it contains obvious propeller blade frequency and frequency doubling noise contribution, thus greatly promoting the radiation noise. Low-frequency noise is the main source of noise, so it desperately needs to effectively control the vibration of thrust bearing. In addition, the radiated noise of shafting mainly comes from shafting vibration. Therefore, the difficulties in vibration control of thrust bearing are analyzed, the current research status of axial vibration of the propulsion shafting and thrust bearing is presented, and then the future research direction is analyzed.

I. Difficulties in thrust bearing vibration control

Large power equipment, such as steam turbine generator set, main steam turbine gear set, main propulsion motor, etc., is characterized by large power, strong excitation, rich low-frequency harmonic wave and so on, and it is the primary control object of stern noise^[1],[2]. At present, large floating-raft vibration isolation technology is adopted to carry out centralized vibration isolation of the main power unit at the stern is the main technical means for foreign advanced submarines, as shown in figure 1 and 2.