Propulsors

Abstract

A propulsor for a marine vessel is described. The propulsor includes a plurality of blades extending from a rotary housing. The blades are distributed around a blade pitch circle diameter of the rotary housing. A mounting plate rotatably mounts the rotary housing to a hull of the marine vessel. A slewing bearing includes a driven ring with a driven gear that is fixed to the rotary housing and a stationary ring fixed to the mounting plate. A diameter of the slewing bearing is at least 0.4 times the blade pitch circle diameter. The propulsor includes a main electric motor with a drive shaft mechanically connected to a driving gear. The driven gear of the slewing bearing and the driving gear define a single-stage transmission gear with a transmission ratio between 5:1 and 15:1.

1 . A propulsor for a marine vessel, the propulsor comprising:
 a rotary housing;   a plurality of blades extending from the rotary housing, each blade having a respective blade axis about which it can be pivoted relative to the rotary housing, and wherein the blades are distributed around a blade pitch circle diameter of the rotary housing;   a slewing bearing comprising a driven ring fixed to the rotary housing and including a driven gear, and a stationary ring adapted to be fixed to the hull of the marine vessel, wherein a diameter of the slewing bearing is at least 0.4 times the blade pitch circle diameter;   a main electric motor with a drive shaft; and   a driving gear mechanically connected to the drive shaft, wherein the driven gear and the driving gear define a single-stage transmission gear with a transmission ratio between 5:1 and 15:1.   
     
     
         2 . The propulsor according to  claim 1 , wherein the driven ring is a radially inner ring, and the driven gear is provided on the radially inner surface of the slewing bearing. 
     
     
         3 . The propulsor according to  claim 2 , wherein the driving gear is positioned radially inside the slewing bearing. 
     
     
         4 . The propulsor according to  claim 1 , wherein the driven ring and the driven gear are formed as separate components that are fixed together to define a unitary driven component of the slewing bearing. 
     
     
         5 . The propulsor according to  any preceding claim 1 , wherein the drive shaft is substantially parallel to the axis of rotation of the rotary housing. 
     
     
         6 . The propulsor according to  claim 1 , wherein the driving gear is mechanically connected to the drive shaft by a main drivetrain that comprises a mechanism for selectively disengaging the drive shaft from the driven ring. 
     
     
         7 . The propulsor according to  claim 6 , wherein the mechanism is a clutch mechanism between the drive shaft and the driving gear. 
     
     
         8 . The propulsor according to  claim 1 , wherein the main electric motor is a liquid cooled permanent magnet motor. 
     
     
         9 . The propulsor according to  claim 1 , further comprising a second main electric motor with a second drive shaft, and a second driving gear mechanically connected to the second drive shaft, wherein the driven gear and the second driving gear define a second single-stage transmission gear. 
     
     
         10 . The propulsor according to  claim 1 , further comprising a plurality of blade actuators, each blade actuator being mechanically connected to a respective one of the blades for pivoting the blade about the blade axis. 
     
     
         11 . The propulsor according to  claim 10 , wherein each blade actuator comprises an electric motor. 
     
     
         12 . The propulsor according to  claim 11 , further comprising:
 an auxiliary electric motor for driving rotation of the rotary housing;   a main power supply; and   an auxiliary power supply;   wherein the main electric motor is electrically connected to the main power supply and the auxiliary electric motor is electrically connected to at least one of the blade actuator electric motors and is configured to receive electrical power recovered by the at least one blade actuator electric motor a during regenerative mode.   
     
     
         13 . The propulsor according to  claim 12 , wherein the auxiliary electric motor is fixed to a stationary part of the propulsor. 
     
     
         14 . The propulsor according to  claim 12 , wherein the auxiliary electric motor is fixed to the rotary housing. 
     
     
         15 . The propulsor according to  claim 1 , wherein the plurality of blades extend from a surface of the rotary housing, and wherein the propulsor further comprises a first empty access volume extending axially from a first access opening in the surface of the rotary housing to a second access opening adjacent the slewing bearing, the first access opening in the surface of the rotary housing being covered by a first removable access panel. 
     
     
         16 . The propulsor according to  claim 15 , wherein the first empty access volume and the first and second access openings are sized and shaped to completely receive the main electric motor therethrough. 
     
     
         17 . The propulsor according to  claims 15 , further comprising a mounting plate rotatably mounting the rotary housing to the hull of the marine vessel, wherein the propulsor further comprises a second empty access volume extending axially from the second access opening to a third access opening in the mounting plate, and wherein the second empty access volume and the third access opening are sized and shaped to completely receive the main electric motor therethrough 
     
     
         18 . The propulsor according to  claim 17 , wherein the third access opening is covered by a second removable access panel. 
     
     
         19 . The propulsor according to  claim 1 , further comprising a mounting plate rotatably mounting the rotary housing to the hull of the marine vessel, wherein the stationary ring of the slewing bearing is fixed to the mounting plate. 
     
     
         20 . The propulsor according to  claim 1 , adapted to be installed into the hull of a marine vessel from below. 
     
     
         21 . A marine vessel comprising at least one propulsor according to  claim 1 . 
     
     
         22 . A method of operating a propulsor according to  claim 11 , the propulsor further comprising an auxiliary electric motor for driving the rotary housing, the method comprising supplying electrical power recovered by at least one of the blade actuator electric motors during a regenerative mode to the auxiliary electric motor. 
     
     
         23 . A method of operating a propulsor according to any of  claim 1  as a turbine, wherein the main electric motor is operated as a generator to generate electrical power that is fed to a main power supply electrically connected to the main electric motor. 
     
     
         24 . A method of repairing or servicing a propulsor according to  claim 16 , wherein:
 the main electric motor is detached from the propulsor;   the first access panel is removed; and   the main electric motor is received completely through the second access opening, the first access volume, and the first access opening.   
     
     
         25 . A method of repairing or servicing a propulsor according to  claim 18 , wherein:
 the main electric motor is detached from the propulsor;   the first and second access panels are removed; and   the main electric motor is received completely through the third access opening in the mounting plate, the second access volume, the second access opening, the first access volume, and the first access opening.