| Water-lubricated bearings have the advantages of green,pollution-free and small friction coefficient,which meet the needs of the development of green ships and are often used in ship stern bearings.However,its operating conditions are relatively bad.Under the action of the large cantilever of the propeller,the part of the water-lubricated stern bearing close to the propeller is subjected to severe bias load,which increases the load on the tail edge of the bearing and even causes local contact.This affects the load-carrying and dynamic characteristics of the water-lubricated bearing.Therefore,it is necessary to improve the bearing capacity of the water-lubricated stern bearing.Therefore,a water-lubricated magnetic-fluid double suspension radial bearing scheme for bias load is proposed with the characteristics of "co-bearing magnetic force and water film force" and "shaft non-uniform magnetic circuit arrangement".It can improve the bearing capacity,and can use the magnetic force to compensate the water film force and correct the tilt.The main research contents of the bearing’s load-carrying characteristics and dynamic characteristics are as follows:(1)The magnetic-hydraulic double suspension radial bearing scheme is designed for bias load,the calculation method of bearing load-carrying characteristics is established,the force analysis of water film force is carried out,and the modeling and calculation method of water film force is proposed;The basic theory of electromagnetism,magnetization methods,analytical and finite element calculation methods of magnetism are introduced.The calculation process of the total bearing capacity of the bearing is established by the calculation of the water film force and the magnetic force.(2)The simulation analysis of load-bearing characteristics of the magnetic-hydraulic double suspension radial bearing facing bias load is carried out.The influence of key structural parameters on bearing load-carrying characteristics is revealed,the magnetic structural parameters are optimized,and the magnetic circuit layout scheme facing the bias load is designed to form an arrangement layout of the upper suction and lower repelling magnetic blocks arranged axially non-uniformly.A bearing scheme was designed to match the water film force and the magnetic force for inclined conditions.The results show that both the structural parameters of the magnet block and the sheath material have an influence on the magnitude of the magnetic force,but the rotational speed has little effect on the magnitude of the magnetic force;Both the eccentricity and the inclination angle have a significant impact on the water film;the addition of magnetic force can improve the bearing capacity,and the uneven distribution of the magnetic force in the axial direction can be used to compensate the water film force and correct the shaft inclination.(3)The dynamic characteristics of the magnetic-hydraulic double suspension radial bearing facing eccentric load are simulated and analyzed,and the dynamic calculation model and method of the bearing are introduced.The 8-parameter calculation method was used for the dynamic characteristics of the water film,the influence of eccentricity,inclination angle and rotational speed on the dynamic characteristics of the water film was analyzed,and the dynamic characteristics of the magnetic force and the dynamic characteristics of the polymer lining were solved by the displacement impedance method.And based on this,the total dynamic characteristics of the bearing are obtained.The results show that the eccentricity,rotational speed and inclination angle have an influence on the dynamic characteristics of the bearing;the total stiffness of the water film and polymer is the total stiffness of the bearing,and the water film damping is the total damping of the bearing.(4)The performance test of the magnetic-hydraulic double suspension radial bearing facing bias load was carried out,and the test analysis showed that: The designed arrangement of magnetic blocks can make the magnetic induction intensity concentrated at the bearing gap;With the change of rotational speed,the stiffness of the bearing hardly changes,only fluctuates in a small range;With the increase of excitation frequency,the overall stiffness of the bearing shows a downward trend,but the magnitude of change is also small. |
