The Research On Lubrication State And Friction And Wear Mechanism Of Water Lubricated Bearings

Water lubricated bearing is a key part of the ship transmission system,and its material performance directly determines the efficiency and stability of the ship.Water lubricated bearings have been used for one hundred years,but at present,most of the water lubricated bearings for domestic ships still rely on imports.At the same time,the water lubricated bearings have some problems,such as stick slip phenomenon,easy wear and so on.Therefore,it is of great significance to study the stick slip phenomenon and wear problems of water lubricated bearings,and to develop new water lubricated transmission bearing materials with better performance.In this paper,the water lubricated transmission bearing is taken as the research object,and the problems such as the stick slip phenomenon and friction and wear performance of water lubricated bearing materials are explored.The actual friction motion between water lubricated bearings in ship transmission system is simplified as a "ring block" friction model,and the stick slip phenomenon and wear characteristics of UHMWPE materials under different conditions are studied.Nano Si C filled UHMWPE / rubber composites were prepared by hot mixing and hot pressing.The adhesion sliding phenomenon and friction and wear properties between the composites and the counterpart steel ring(GCr15)under different conditions were evaluated by using mrh-3 ring block friction and wear tester.The influence of different degree of water lubrication conditions on stick slip phenomenon was quantitatively analyzed,and the change of wear surface was characterized by optical microscope(OM),scanning electron microscope(SEM)and non-contact optical three-dimensional profilometer.Based on the experimental research and theoretical analysis,the mechanism of stick slip phenomenon and friction and wear of water lubricated bearing materials are analyzed from the micro level.The main conclusions are as follows:(1)Under low speed,heavy load,start-up and stop conditions and different water lubrication conditions,the viscosity slip phenomenon of UHMWPE Composite Modified by nano filler has been improved obviously.When the lubrication is sufficient,the viscosity slip phenomenon of water lubricated bearing can be improved by increasing the speed and reducing the load ratio.(2)The wear mechanism of UHMWPE composites is different under different water lubrication conditions.Under the full water condition,only a little fatigue wear occurs.When the water quantity is reduced by half,adhesive wear gradually appears;when the water quantity is reduced to a quarter,adhesive wear appears earlier.(3)The working conditions and nano fillers have great influence on the composites.When the load increases,the friction coefficient and wear rate of UHMWPE material decrease gradually;with the increase of the proportion of nano filler,the rubber particle shedding on the worn surface of the sample is effectively improved,and the wear rate and friction coefficient decrease significantly.In conclusion,nano fillers can effectively improve the stick slip phenomenon and tribological performance of water lubricated bearings,reduce the noise pollution of ship transmission system,increase the service life of bearings,improve the safety performance of ships,and increase the environmental protection,which is of great significance to the development of ship transmission system bearings in China.