Submersible electric thruster

Abstract

A submersible electric thruster operable to propel underwater vehicles, surface vehicles, amphibious vehicles, etc. The submersible electric thruster includes a stator assembly having a base, stator, windings, and bearings and an external rotor assembly having a cylindrical arrangement of permanent magnets with a hub that is secured to a shaft. The stator forms the center of the motor and the permanent magnets spin around the stator. A propeller hub is integrally connected to the rotor assembly with angularly spaced propeller blades extending radially from the propeller hub. An annular nozzle surrounds the propeller and motor, forming an inlet and outlet for water flow. A nose cone is connected to the stator assembly and a tail cone is integrally connected to the nozzle assembly. Supporting arms may extend from the stator assembly to support the nozzle and/or supporting arms may extend from the nozzle to the support the tail cone.

What is claimed: 
     
         1 . A submersible electric thruster comprising:
 a stator assembly having a stator and electrical windings;   a rotor assembly having a plurality of magnets arranged radially outwardly of the electrical windings and configured to rotate about the electrical windings when driven by electromagnetic forces provided by the stator and electrical windings;   a propeller with a hub co-rotatably connected to the rotor assembly, the propeller having at least one propeller blade extending from the hub;   an internal chamber that contains the stator and electrical windings;   wherein the thruster is configured to allow at least the internal chamber to be flooded with water when the thruster is submerged; and   a protective barrier that encapsulates the stator and electrical windings without enclosing any air cavities, the protective barrier being configured to make direct contact with the flooded water to thereby prevent the flooded water from contacting the stator and electrical windings when the thruster is submerged.   
     
     
         2 . The submersible electric thruster according to  claim 1 , wherein the protective barrier is an epoxy coating. 
     
     
         3 . The submersible electric thruster according to  claim 1 , wherein the protective barrier is a vacuum degassed coating. 
     
     
         4 . The submersible electric thruster according to  claim 1 , wherein the protective barrier is an overmolded plastic coating. 
     
     
         5 . The submersible electric thruster according to  claim 1 ,
 wherein the stator has axial ends and a radially outer surface extending between the axial ends; and   wherein the internal chamber is at least partially defined by internal surfaces of the rotor assembly that are spaced apart from both the radially outer surface of the stator and at least one of the axial ends of the stator.   
     
     
         6 . The submersible electric thruster according to  claim 1 , wherein the thruster has a flow passage extending radially inwardly across a radially outer portion of the hub, the flow passage being configured to allow water to flow into and flood the internal chamber when the thruster is submerged. 
     
     
         7 . The submersible electric thruster according to  claim 6 , wherein the flow passage is formed between an axial end portion of the hub and an adjacent portion of a base of the stator assembly. 
     
     
         8 . The submersible electric thruster according to  claim 7 , wherein the axial end portion of the hub and the adjacent portion of the base of the stator assembly each have axially extending projections that radially overlap with each other to form the flow passage with a non-linear path configured to restrict the ingress of debris into the internal chamber. 
     
     
         9 . The submersible electric thruster according to  claim 1 , wherein the rotor assembly includes a shaft extending through the stator assembly that is connected co-rotatably to the plurality of magnets. 
     
     
         10 . The submersible electric thruster according to  claim 1 , wherein the thruster further includes a nozzle that is connected to the stator assembly. 
     
     
         11 . A submersible electric thruster comprising:
 a stator assembly having a stator and electrical windings, the stator having axial ends and a radially outer surface extending between the axial ends;   a rotor assembly having a plurality of magnets arranged radially outwardly of the electrical windings and configured to rotate about the electrical windings when driven by electromagnetic forces provided by the stator and electrical windings;   a propeller with a hub co-rotatably connected to the rotor assembly, the propeller having at least one propeller blade extending from the hub;   an internal chamber that contains the stator and electrical windings;   wherein the thruster is configured to allow at least the internal chamber to be flooded with water when the thruster is submerged, such that the axial ends of the stator are surrounded by the flooded water; and   at least one protective barrier that extends radially inwardly to directly contact each of the axial ends of the stator with corresponding inner sides of the at least one protective barrier, and wherein the at least one protective barrier has opposite outer sides configured to make direct contact with the flooded water that surrounds the axial ends of the stator to thereby prevent the flooded water from contacting the axial ends of the stator and the electrical windings when the thruster is submerged.   
     
     
         12 . The submersible electric thruster according to  claim 11 , wherein the thruster is configured to allow the flooded water to also surround the radially outer surface of the stator, wherein the at least one protective barrier is configured to extend axially to directly contact the radially outer surface of the stator, and wherein the at least one protective barrier makes direct contact with the flooded water that surrounds the radially outer surface of the stator to thereby prevent the flooded water from contacting the radially outer surface of the stator when the thruster is submerged. 
     
     
         13 . The submersible electric thruster according to  claim 11 , wherein the protective barrier encapsulates the stator and electrical windings without enclosing any air cavities. 
     
     
         14 . The submersible electric thruster according to  claim 11 , wherein the protective barrier is an epoxy-dipped coating. 
     
     
         15 . The submersible electric thruster according to  claim 11 , wherein the protective barrier is a vacuum degassed coating. 
     
     
         16 . The submersible electric thruster according to  claim 11 , wherein the protective barrier is an overmolded plastic coating. 
     
     
         17 . The submersible electric thruster according to  claim 11 , wherein the internal chamber is at least partially defined by internal surfaces of the rotor assembly that are spaced apart from both the radially outer surface of the stator and at least one of the axial ends of the stator. 
     
     
         18 . The submersible electric thruster according to  claim 11 , wherein the thruster has a flow passage extending radially inwardly across a radially outer portion of the hub, the flow passage being configured to allow water to flow into and flood the internal chamber when the thruster is submerged. 
     
     
         19 . The submersible electric thruster according to  claim 18 , wherein the flow passage is formed between an axial end portion of the hub and an adjacent portion of a base of the stator assembly, the axial end portion of the hub and the adjacent portion of the base of the stator assembly each having axially extending projections that radially overlap with each other to form the flow passage with a non-linear path configured to restrict the ingress of debris into the internal chamber. 
     
     
         20 . The submersible electric thruster according to  claim 11 , wherein the rotor assembly includes a shaft extending through the stator assembly that is connected co-rotatably to the plurality of magnets; and wherein the thruster further includes a nozzle that is connected to the stator assembly.