Study on Lubrication Characteristics of Trapezoidal Groove for Planetary Gear Sliding Bearing

Abstract

Abstract. It has been proven to be an effective method for reducing the friction and wear of two contact surfaces by introducing a hydrodynamic lubrication mechanism. A linear trapezoidal groove was proposed to accommodate the bidirectional rotation of the planetary gear. Cavitation and fluid rotation centrifugal forces were analyzed by the finite control volume method. The influence of the structural parameters of the groove, such as profile inclination of trapezoidal groove, film thickness ratio, groove number and groove width ratio, on the hydrodynamic lubrication characteristics of the groove were investigated. The results show that an optimal interval value is existent for trapezoidal profile inclination, film thickness ratio and groove number, and simultaneously meeting the maximum bearing capacity and minimum friction coefficient for the fluid lubrication. The cross-sectional area of the groove and rotating centrifugal force have a great influence on the flow rate and cavitation rate of the oil film. When other parameters are unchanged, the trapezoidal profile inclination is better than that of the rectangular groove and the triangle groove in a certain range. The cavitation rate was commonly determined with the oil flow and centrifugal force, but the bearing capacity could be hardly influenced.