Tilting Pad Journal Bearing Pivot Design For High Load Applications.

Abstract

Reducing pivot stress, pivot wear and preventing pivot failure are major design challenges encountered by tilting pad bearing designers in the extremely high load regime where the bearing unit load may often range up to 500 psi. In an attempt to address these design challenges, simple equations are presented for the calculation of pivot stiffness and the resulting pivot contact stress for a nonaligning cylindrical pivot, a self-aligning spherical pivot and a self-aligning sphere-in-a-cylinder pivot. The effect of the pivot's flexibility on the bearing's stiffness and damping properties is also investigated. Comparisons are made between the three pivot designs. Utilizing the simple equations for pivot stress, a method to determine proper pivot sizing to prevent pivot failure due to high loads is outlined using a spherical pivot as a design example. A finite element stress analysis is also considered and the results compared to the simplified analysis.