Effect of Lubricating Material on the Slewing Performance of a Sliding Slewing Bearing

The common slewing bearings used by large tonnage cranes are bogie slewing bearing and roller slewing bearing. They have different characteristics that affect the lifting capacity. Sliding slewing bearing is a new type of slewing bearing with compact-sized, low barycenter, high stability, large bearing area and good bearing capacity. However, there are some problems need to be studied, such as the rail pressure balance between the slides and the fixed orbits, sliding friction in slewing condition, etc. Polytetrafluoroethylene (PTFE) is a lubricating material with low friction coefficient and high endurance. Contact analytical mode of the sliding slewing bearing and the lubricating layer is established in FEM (Finite Element Method). Frictional resisting moments are analyzed by transient analysis method in two sliding friction condition: steel-steel contact between the slides and the fixed orbits; add lubricating material between the sliding surfaces. The effect of lubricating layer on the rail pressure distribution of the slide in the circumferential direction and the radial direction has been studied. After adding the lubricating layer, there is a significant decrease in the frictional resisting moments of the slewing bearing and the contact regions have been expanded from the below of the reinforcing plate to the whole bearing surface, which makes the rail pressure distribution of the bearing surface more balanced.