Study On Friction-induced Film-forming Mechanism Of Spherical Plain Bearings With Rigid-flexible Spherical Counter-pairs

Self-lubricating spherical plain bearings are a kind of spherical bearing with a layer of self-lubricating liners inlaid or bonded on inner spherical surface of the outer rings, have characteristics of self-lubricating, maintenance-free, long life, heavy load, etc. Therefore, the bearings can meet the requirement of railway machinery, light industry, engineering machinery and other areas. As self-lubricating spherical plain bearings are widely used in various areas, especially in the high-tech areas such as high-speed rail, aero-space, military industry, etc., and its demand greatly increased. Therefore, the performance of self-lubricating spherical plain bearings are put forward higher requirements such as service properties, reliability, service life, etc. However, when spherical plain bearings work at severe conditions such as heavy load, high torque and so on, often lose the working characteristics because of the tribological properties of the bearings sharp declined due to the fitting surface between inner and outer rings generate agglutination or excessive clearance, which ultimately result in bearing failure. Due to the transfer film generally form in the process of the relative sliding between self-lubricating liners and inner spherical surface, and the state of transfer film formation will directly affect the working characteristic, friction and wear properties and service life of self-lubricating spherical plain bearings. Therefore, to investigate the friction-induced film-forming mechanism of the spherical plain bearings with rigid-flexible spherical counter-pairs will be of great significance for improving the service properties and service life of the bearings. The self-lubricating spherical plain bearings with PTFE/Kevlar woven liners were researched. The peeling strength and tribological properties of spherical plain bearings with different pre-treatments were tested. The effects of pretreatment methods on the bonding properties and tribological properties of spherical plain bearings were investigated, and the properties of spherical plain bearings influenced on the film-forming properties of the bearings were analyzed. The effect of pretreatment methods on the friction-induced film-forming mechanism and wear mechanism of the spherical plain bearings with rigid-flexible spherical counter-pairs were in-depth researched. The main research works are as follows.The peeling test of spherical plain bearings with different pre-treated liners was conducted. The influence rules of pretreatment methods on the bonding properties of spherical plain bearings were analyzed. The tribological properties of spherical plain bearings with unmodified and modified liners were tested under a constant load, a steady swing frequency and different swing time. The effect of pretreatment methods on the friction coefficient, wear loss and friction temperature of spherical plain bearings were explored.The microstructure and elementary composition of the worn surface of unmodified and modified liners were analyzed by scanning electron microscope(SEM), energy disperse spectroscopy(EDS) and x-ray photoelectron spectroscopy(XPS). The bonding properties and tribological performance of spherical plain bearings with different pre-treated liners influenced on the film forming properties of the bearings were investigated. The effect of pretreatment methods on the friction-induced film-forming mechanism and wear mechanism of the spherical plain bearings with rigid-flexible spherical counter-pairs were in-depth researched. The physical models of the friction-induced film-forming process for spherical plain bearings were created. The results have a certain reference vale to further improve the film-forming properties of spherical plain bearings during sliding wear, and thus increase the working properties and service life of self-lubricating spherical plain bearings.