Abstract: The lubrication mechanism and floating characteristics of the self hydrostatic fluid pivot floating bearing were studied. First of all, the continuous flow equation between the inner static pressure hole and the outer static pressure cavity is derived. The formula for the thickness of the oil film in the inner and outer layers and the maximum swing angle of the pad are proposed. The finite element method is used to solve the Reynolds equations of inner layer dynamic pressure lubrication and outer layer hydrostatic pressure lubrication. The initial working mechanism of the fluid pivot floating bearing was analyzed. The important conclusion that the bearing floating needs to meet two requirements is obtained: the outer layer of the first bearing bush has a certain initial gap; the second should meet the requirements of a certain static pressure cavity area ratio. In theory, a fluid pivot bearing with a journal of 100 mm is analyzed in the initial working state. If the condition of bearing shell floating is to be satisfied, that is, the outer oil film force is greater than or equal to the inner oil film force, the ratio of the area of the static pressure cavity should be between 0.16 and 0.18. On this basis, the Newton-Rapson method is used to establish a numerical iterative calculation model for single-pad fluid pivot bearings. The variation of the bearing static characteristics with the eccentricity is analyzed when the single-pad fluid pivot floating bearing is loaded. Under the load of a single pad, the ratio of the floating height of the bottom and the flow rate of the static pressure orifice gradually decreases as the eccentricity increases. At the same eccentricity, the diameter of the static pressure hole increases, and the floating height and the flow rate of the static pressure hole increase accordingly. The pressure of the static pressure chamber, the bearing capacity of the pad, the maximum oil film pressure of the inner layer and the friction power consumption of the inner layer all gradually increase with the increase of the eccentricity. In addition, the frictional power consumption of the outer layer increases less as the eccentricity increases, and gradually stabilizes at a higher eccentricity. The inner friction power consumption is much larger than the outer friction power consumption. When the fluid pivot single pad is loaded, and the bearing is subjected to static load, the pad swing angle is 0 °.By comparing with the experimental data of the existing literature, the accuracy of the calculation model in this paper is verified.

Key words: self-hydrostatic, fluid pivot, tilting pad, oil film bearing, floating characteristics