Marine propulsion device

Abstract

A marine propulsion device such as an outboard motor includes a submersible electric motor having a propeller connected directly with the drive shaft of the motor. The motor is an efficient brushless motor having symmetrical elliptical coils connected with a stator which generate magnetic flux when current is passed through the coils to rotate a rotor for driving the drive shaft. The motor is arranged in a housing having a nozzle connected with a rear portion thereof which surrounds the propeller to reduce cavitation. Cooling fins are provided on the outer surface of the housing to assist with cooling the motor and a motor controller arranged in the housing.

1 . A marine propulsion device, comprising
 (a) a submersible housing containing a brushless electric motor having a longitudinal drive shaft extending from said housing; and   (b) a propeller connected with said drive shaft and being driven for rotation by said motor.   
   
   
       2 . A marine propulsion device as defined in  claim 1 , wherein said motor includes
 (a) a cylindrical stator having a longitudinal axis and defining a chamber;   (b) a rotor arranged within said stator chamber coaxial with said stator, said drive shaft being connected with said rotor;   (c) a plurality of magnets connected with an outer surface of said rotor; and   (d) a plurality of symmetrical coils connected with an inner surface of said stator, each of said coils comprising a conductor wound in an elliptical configuration, a long axis of each coil being parallel with the stator longitudinal axis, whereby when current is supplied to said coils, said coils produce a magnetic flux which acts on said magnets to cause said rotor to rotate with respect to said stator.   
   
   
       3 . A marine propulsion device as defined in  claim 2 , wherein said housing includes a nozzle extending rearwardly therefrom, said propeller being arranged within said nozzle, whereby said nozzle reduces cavitation resulting from rotation of said propeller. 
   
   
       4 . A marine propulsion device as defined in  claim 3 , wherein said nozzle has a truncated conical configuration. 
   
   
       5 . A marine propulsion device as defined in  claim 3 , wherein said housing includes a plurality of longitudinal cooling fins arranged in spaced relation about the housing exterior surface. 
   
   
       6 . A marine propulsion device as defined in  claim 5 , and further comprising a controller arranged within said housing and connected with said motor. 
   
   
       7 . A marine propulsion device as defined in  claim 2 , and further comprising means for connecting said housing with a vessel. 
   
   
       8 . A marine propulsion device as defined in  claim 7 , wherein said connecting means comprises a bracket connected with a vessel transom and a shaft connected between said bracket and said housing. 
   
   
       9 . A marine propulsion device as defined in  claim 8 , and further comprising a rudder connected with said shaft adjacent to said housing. 
   
   
       10 . A marine propulsion device as defined in  claim 9 , and further comprising a control system connected with said bracket. 
   
   
       11 . A marine propulsion device as defined in  claim 10 , wherein said control system includes means for rotating said shaft relative to said bracket to steer the vessel and means for supplying electric current to said motor.