Research On Optimization Design And Lubrication Characteristic Of Marine Motor Sliding Bearing

Marine motor plain bearings are important support components for ship propulsion shafts.The performance of its good or bad will directly affect the ship's overall power,economy and life.With the motor sliding bearings relative to ordinary sliding bearings,the situation is more complex.When the ship is voyaging,due to the impact of waves and other factors,there will be a swing.The sliding bearing working plane will be inclined to different degree,which puts forward higher requirements on bearing performance.Therefore,it is of great significance to study the design of high reliability marine motor plain bearings to promote the development of China's shipbuilding industry.Adaptive weight particle swarm optimization(APSO)is used to optimize the structure of marine motor plain bearings.And its dynamic and static characteristics analysis and calculation formula was derived.The stability of the bearing-rotor system is calculated and its stability was analyzed.The test of the bearing of the marine motor sliding bearing test bench was carried out to verify the rationality and correctness of the designed bearing.The details are as follows:(1)The adaptive particle swarm optimization(APSO)algorithm is used to optimize the sliding bearing.The optimal mathematical model of horizontal sliding bearing structure is established.After solving the three single objective functions respectively,the multi-objective optimization model is obtained.And it is optimized and compared with the original design model.(2)The finite difference method is used to solve the constant Reynolds equation under isothermal condition.The static characteristics of the sliding bearing are obtained,and the influence of the structural parameters and so on is analyzed.Considering the viscosity-temperature effect,the synthetic Reynolds equation and the energy equation are solved by the step method and the difference method.The distribution of the temperature field and the static characteristics are obtained.The influence of the viscosity-temperature effect on the static characteristics is analyzed.(3)The dynamic characteristics of the sliding bearing are studied,and the unsteady Reynolds equation is deduced by the pressure perturbation method.The eight dynamic coefficient parameters of the bearing-rotor system based on the small perturbation are obtained.And the influence of structural parameters on stiffness coefficient and damping coefficient is analyzed.The mechanism of oil film instability is analyzed,and the instability speed is deduced and calculated.And the influence ofstructural parameters on the speed of instability is analyzed.(4)The test of the bearing of the marine motor sliding bearing test bench was carried out.According to the actual conditions,routine tests and impact tests were conducted,which simulated working condition of the bearing in the level,tilt,impact and other working conditions.The temperature change of the lubricating oil under different working conditions,the change of the test bearing temperature and the wear of the bearing under various working conditions are obtained.The results show that the eccentricity and the width diameter ratio of the bearing have different effects on the static and dynamic characteristics of the bearing and affect the stability of the bearing-rotor system.Therefore,in the design of sliding bearing structure,the impact of eccentricity and width ratio must be considered.Under the same conditions,the effect of viscosity and temperature on bearing static performance is obvious.In the design of bearings,especially in the case of high-speed,the impact of temperature can't be ignored.The experimental tests of the marine motor plain bearings obtained by APSO optimization were carried out.The temperature rise and other performance are stable,which verifies the rationality and correctness of the designed bearing.