Study On Self-Iubricating Technology And Property On Micro-textured Surface Of Sliding Bearing Couple

With the continuous development of modern industrial technology, the requirements for the bearings at the special working conditions are becoming higher and higher, which leads to the difficulty for the liquid lubrication of full lubrication. Micro textured self lubrication technology emerges as the times require, and acts as an effective way of self-lubrication of sliding friction pairs in harsh environments. In this paper, the sliding friction properties and the mechanism of the laser micro textured self-lubrication surface in atmospheric environment and liquid mediumFirstly, micro texturing process test was carried out by using laser surface texturing(LST) technology for the purpose of the effect of the distance from laser head to the sample surface, pulse number, and single pulse energy on the parameters of the micro dimple on the surface. The different coating surface were textured by the appropriate laser processing parameters with the view of the effect of the single coating material and the composite coating material on the dimple volume and the slag volume around the dimple, on the basis of which orthogonal test was carried out to explore the best formula of the mixed coating. Secondly, solid lubricant was filled into the dimple on the surface of GCr15 bearing steel in order to make the comparison of the different filling methods. The different solid lubricants were respectively filled into the dimple by the better ―holding temperature and pressure‖ filling method to study their friction properties. Again, the sliding friction and wear test was carried out by the sliding friction pair of the ring-ring surface to study the influence of surface lubrication treatment, texture density, rotational speed and load on the sliding friction properties of micro textured self-lubrication surface. Finally, in order to further improve the lubricating effect of the micro textured surface filled with composite solid lubricant, the lubricating fluid was combined to study the effect of surface lubrication treatment, texture density, rotational speed and load on the sliding friction properties of micro textured self-lubrication surface in liquid medium. And comparative effect of surface lubrication treatment at different conditions on the sliding friction properties was made. The corresponding conclusions are as follows.(1) Good morphology can be obtained when the distance between the laser head and the sample surface is 1.5mm. The depth and diameter of the micro dimple respectively increases and increases before decreasing slowly with the increase of the laser pulse numbers. The diameter and depth of micro dimple increased with the increase of the single pulse energy, and the increasing range of the micro dimple decreased slowly.(2) Compared to the non-coating samples, the green material and water glass coating can significantly improve the absorption rate of laser and the surface quality, among which the best performance is green material with the erosion volume of the dimple increased by 29.4% and the slag volume around the dimple decreased by 43%. Water glass / green material composite coating(C-8) can not only better improve the laser surface texturing machining efficiency compared to single water glass(C-2) and green materials(C-3), and the effect is higher than the sum of single C-2 and C-3 coating, but does not affect the laser texture processing surface quality.(3) The different filling methods were compared from many aspects, such as the filling rate of the single dimple and the whole texturing surface, sliding friction properties, and so on. The results showed that: the comprehensive performance of ―holding temperature and pressure‖ filling method was obviously better than that of ―mold hot pressing‖ filling method.(4)The sliding friction properties of the nanometer solid lubricant are better than that of the micron lubricant. The optimal formula of compound lubricant is Gr:Mo S2:PI:CNTs=4:1:0.5:0.4. Among them, the primary and secondary order of the influence of various factors on the friction coefficient is: CNTs > Gr > PI > Mo S2.(5) Micro textured self-lubrication technology can greatly improve the friction and wear properties of smooth surface. The surface friction coefficient and the wear rate of the sample increase before decreasing with the increase of the texture density and the best texture density is 33.2%~41.7%. The friction coefficient decreases with the increase of the load. What’s more, the solid lubricant raises from the dimple and stack in a certain gradient along the sliding direction.(6) The friction and wear properties of the micro textured self-lubrication surface in liquid(lubricating oil and grease) medium are obviously improved in liquid(lubricating oil and grease) medium on the conditions of different load and rotational speed.