A thruster for use in underwater applications, including a stator assembly
having an encapsulated set of coils and a rotor assembly having an
encapsulated set of permanent magnets. Two ring-shaped rotor bearings,
incorporating both thrust bearing surfaces and journal bearing surfaces,
are mounted on the rotor assembly, for bearing engagement with
corresponding bearing surfaces of ring-shaped bearing assemblies mounted
on the stator assembly. The rotor bearings include radial grooves that
form a centrifugal pump for drawing sea water through a filter assembly,
which then directs the filtered water past the stator coils, for cooling,
and past the bearing surfaces, for cooling and lubrication. The stator
bearing assemblies are made up of a number of arc-shaped segmental
bearings having specially configured cantilevered arms that facilitate the
creation of a lubricating film of filtered sea water between the bearing
surfaces. The rotor assembly has a shaftless configuration, with a
ring-shaped rotor body with a set of inwardly projecting, symmetrically
shaped blades.
