Research on Working Mechanism and Structural Optimization of High-Speed Bearing of Tricone Bits Based on Finite Difference Method

Abstract

To analyze the working mechanism of the floating sleeve bearing of the cone bit, the life of the floating sleeve bearing was tested. The experimental results show that adhesive wear will form on the bearing surface with the increase in temperature, which is the main cause of bearing failure. This article establishes the Reynolds equation and energy equation of the oil film based on the theory of dynamic pressure lubrication of sliding bearings. The equation was numerically solved based on the finite difference method. It determines the rotational speed ratio at the equilibrium based on the trend of the frictional torque and then corrects the eccentricity in the iterative calculation process so as to analyze the tribological performance of the bearings in equilibrium under different clearance ratios. Among them, the improper configuration of the internal and external clearance ratio leads to the increase of the friction torque and the reduction of the bearing capacity. For floating sleeve bearings, the configuration with a large internal clearance and small external clearance should be adopted. Finally, the bearing structure is optimized and numerical calculations show that the tribological performance of the new type of bearings is significantly improved compared with that of ordinary cone bit bearings.