Optimal design and experimental verification of fluid dynamic bearings with high load capacity applied to an integrated motor propulsor in unmanned underwater vehicles

We developed fluid dynamic bearings (FDBs) for application in an integrated motor propulsor (IMP) of an unmanned underwater vehicle. The structure of the FDBs is composed of plain and grooved journal and thrust bearings, and sea water is used as the fluid lubricant. The Reynolds equation and their perturbation equation were solved by applying the finite element method (FEM) to calculate static and dynamic coefficients. We developed optimal FDBs with high load capacity via an optimization problem of the multi-objective function of radial and axial load capacities and the constraint equations of friction, stiffness, and damping coefficients. Finally, we prototyped the optimal FDBs with high load capacity and verified the load capacity and friction torque of the FDBs via experiments.