Influence Of Surface With Laser Microcavities On Tribological Properties Of Spherical Bearing Under Grease Lubrication

Spherical bearing is widely used in many fields, such as engineering, hoist, agricultural machinery, vehicle and train and so on, because of its characters of simple structure, small volume and excellent carrying capacity. The work of improving spherical bearing’s tribological properties and extending the working life has attracted broad attention.In order to study the influence of microcavities on the tribological properties of grease lubricated spherical bearings, four kinds of specimens are designed and manufactured which have the same surface arithmetic average height and the area density of microcavity are7%,10%,15%and21%respectively. The surfaces of specimens are scanned by Talysurf CCI3D non-contact surface profiler and characterized through volume parameter in ISO25178. With the lubrication of the lithium grease, a series of friction and wear experiments under operating conditions of different load and velocity are conducted on modified HDM-20end-face tribo-tester, the correlations between surface parameters and friction coefficient are studied. Height parameters of arithmetical mean height and kurtosis, functional parameters of peak material volume, core void volume and valley void volume of the scale limited surface, feature parameters of mean dale volume were chosen to characterize surface topography. The results show that the surface with the area density of microcavity21%reduce friction coefficient and temperature increase compared to none laser texture surface. As each of the parameters has different effect on tribological properties, it is beneficial for the tribological design of grease lubricated spherical bearing through the combination of height parameters, functional parameters, feature parameters and so on.Based on experiment analysis, finite element model of spherical bearing was founded by ANSYS. Deformation and pressure distribution of spherical bearing under the load cases of axial load, radial force and complex loading are analyzed respectively. The influence of the lubricating groove on the contact stress of spherical bearing is also studied. The results show that lubricating groove can reduce the contact stress effectively. The simulation and experiment results are compared to show the validity of the simulation work. The results obtained in this paper on the influence of surface with laser textured microcavities on tribological properties of grease lubricated spherical bearing is useful for the tribological design of grease lubricated spherical bearing.