The Structural Optimum of Hydrostatic Thrust Bearings to Avoid Cavitation

Cavitation of oil film is harmful for all kinds of hydrostatic bearings, so the method to avoid cavitation in hydrostatic thrust bearings by optimizing the structure of bearings is proposed in this study. Based on the pressure distribution expressions of two kinds of hydrostatic thrust bearings (circular recess and no recess), considering the boundary conditions of pressure distribution, the threshold conditions to avoid cavitation are obtained. The reliability of these threshold conditions is illustrated by applying the threshold conditions to calculate the pressure distributions of hydrostatic thrust bearings. For hydrostatic thrust bearings with a non-dimensional recess radius larger than 0.607, an appropriate choice on the value of film thickness ratio could effectively avoid cavitation. If the non-dimensional recess radius of bearings is less than 0.607, the inertial parameter has a threshold value determined by recess radius, radius of supply hole, and film thickness ratio. For the bearing with no recess, the threshold value of inertial parameter is only determined by the radius of supply hole. And the results in this study could be applied for the design of hydrostatic thrust bearing to avoid cavitation.