| Woven liner-type self-lubricating spherical plain bearings are used in the aircraft’s landing gear,wings and operating systems,as well as the steering and braking systems of vehicles.Their performance is directly related to the safety of equipment and personnel.Lightweighting is an important indicator in the aviation field.The research and development and use of high specific strength aluminum alloy spherical plain bearings have an important role in improving aircraft dead time.In addition,changes in ambient temperature will directly lead to changes in the lubricating performance of the spherical plain bearings as well as reduced mechanical properties,so it is necessary to explore the influence law and mechanism of the ambient temperature on the performance of self-lubricating spherical plaint bearings.The ABAQUS finite element analysis software was used to establish a static and thermal coupling model of the self-lubricating spherical plain bearing.The ferrule was given 2024 aluminum alloy and GCr15 material properties.From the static analysis,it can be known that the deformation and the growth rate of the aluminum alloy bearing are larger than the GCr15 bearing with the increase of the load,but the contact stress is reduced and the distribution is more uniform.Considering the influence of frictional heat on the performance of the two types of bearings,the results show that the time required for the liner temperature of the aluminum alloy spherical plain bearings to stabilize is shorter,and the stress and temperature distribution on the ring and liner are lower than the GCr15 bearings and the distribution is more uniform.Finally,the correctness of the finite element analysis is verified by experiment.The peel strength of the liner was studied at different temperatures.The two bonding directions of liner A(PTFE fiber along the width of the bearing)and B(PTFE fiber along the circumference of the bearing)were compared.The effect of peeling strength was found that the peeling strength of the spherical plain bearing liners of the two bonding directions increased with the increasing of temperature,And the bonding performance of B bonding direction is better than A.The friction and wear test system of the spherical plain bearing was used to study the tribological performance of the spherical plain bearing under the ambient temperature of 25～145℃.It was found that the degradation of the spherical plain bearing performance can be divided into three stages: running-in period,plateau period,rapid degradation period.The increase in ambient temperature will shorten the running-in period,and the ambient temperature above 85 ℃ will shorten the stationary period and make the bearing quickly enter the rapid degradation period.A LSCM was used to characterize the coverage of the transfer film and the three-dimensional morphology of the friction surface of the liner after wear.It was found that the transfer film coverage was the largest and the friction surface roughness was the smallest when the ambient temperature was 85 ℃.Then the elements in the transfer film were analyzed by SEM and EDS.Finally,it is concluded that the form of bearing wear is mainly abrasive wear and adhesive wear.Spherical plain bearing lubrication is determined by the PTFE transfer film.An increase in the ambient temperature can promote the formation of the PTFE transfer film and improve the anti-friction effect,but excessive temperature will reduce the wear resistance of the transfer film and reduce the anti-friction effect.In summary,aluminum alloy spherical plain bearings are not only lighter than steel spherical plain bearings,but also have more uniform wear and longer life.The research results in this article will provide a certain theoretical basis for the lightweight design and research and development of spherical plain bearings.It will have important engineering value for bearing selection and maintenance planning,and improve the life and reliability of the whole machine. |
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