Marine propulsion unit

Abstract

A marine propulsion unit has at least one motor for rotating a pitchable propeller around an axis. The pitchable propeller is connected with a first shaft and a second shaft, the first shaft being rotated by a first power way and the second shaft being rotated by a second power way. The first power way and the second power way are controllable independently of each other so that a first rotation speed (rpm) of the first shaft and a second rotation speed (rpm) of the second shaft can vary in relation to each other. A coupling is arranged between the first shaft, the second shaft and the pitchable propeller for changing a pitch angle of the pitchable propeller when the first rotation speed and/or second rotation speed vary in relation to the other.

1 . A marine propulsion unit for a marine vessel, comprising
 at least one motor for rotating a pitchable propeller around an axis,   the pitchable propeller being connected with a first shaft and a second shaft,   the first shaft being rotated by a first power way and the second shaft being rotated by a second power way,   wherein the first power way and the second power way are controllable independently of each other so that a first rotation speed (rpm) of the first shaft and a second rotation speed (rpm) of the second shaft can vary in relation to each other,   wherein a coupling is arranged between the first shaft, the second shaft and the pitchable propeller for changing a pitch angle of the pitchable propeller when the first rotation speed and/or second rotation speed vary in relation to the other.   
     
     
         2 . The marine propulsion unit of  claim 1 , wherein the coupling comprises a first gear and a second gear, the first shaft is directly connected to the second gear and the second shaft is directly connected to the first gear. 
     
     
         3 . The marine propulsion unit of  claim 1 , wherein the pitchable propeller has a plurality of propeller blades, each propeller blade being connected to a blade gear. 
     
     
         4 . The marine propulsion unit of  claim 3 , wherein the pitchable propeller has a first blade and a second blade, the first blade is connected to a first propeller gear and the second blade is connected to a second propeller gear. 
     
     
         5 . The marine propulsion unit of  claim 2 , wherein the first gear and the second gear are connected to the propeller gears. 
     
     
         6 . The marine propulsion unit of  claim 1 , wherein the first rotation speed and the second rotation speed are equal whereby the pitchable propeller is rotating with a constant pitch. 
     
     
         7 . The marine propulsion unit of  claim 1 , wherein the first rotation speed or the second rotation speed is different to the other whereby the propeller gears will rotate so that a pitch angle of the pitchable propeller blades will change. 
     
     
         8 . The marine propulsion unit of  claim 1 , wherein the first power way is a first belt drive, and the second power way is a second belt drive. 
     
     
         9 . The marine propulsion unit of  claim 1 , further comprising a control unit being operatively connected with the motor, the first power way and/or the second power way. 
     
     
         10 . The marine propulsion unit of  claim 1 , wherein the first rotation speed is different to the second rotation speed thereby providing that a pitch angle of the pitchable propeller is changing. 
     
     
         11 . The marine propulsion unit of  claim 10 , wherein the control unit is configured to control the first power way and/or the second power way on basis of vessel data received from the marine vessel. 
     
     
         12 . The marine propulsion unit of  claim 11 , wherein the vessel data relates to power consumption, modes of operation of the marine vessel, torque of the motor, load of the marine vessel, speed of the marine vessel, or a combination thereof. 
     
     
         13 . The marine propulsion unit of  claim 11 , wherein the control unit is configured to adjust the pitch angle of the pitchable propeller on basis of the vessel data. 
     
     
         14 . The marine propulsion unit of  claim 9 , wherein the control unit is configured to control the first power way and/or the second power way on basis of input data received from an input unit operated by an operator. 
     
     
         15 . The marine propulsion unit of  claim 14 , wherein the control unit is configured to adjust the pitch angle of the pitchable propeller on basis of the input data. 
     
     
         16 . The marine propulsion unit of  claim 1 , further comprising a second motor, the first motor is directly connected with the first shaft and the second motor is directly connected with the second shaft, or they are connected via the first power way and the second power way, respectively. 
     
     
         17 . The marine propulsion unit of  claim 16 , wherein the control unit is configured to control the rotation of the first motor and the second motor for adjusting the pitch angle of the pitchable propeller. 
     
     
         18 . The marine propulsion unit of  claim 1 , wherein the motor is an electric motor or a combustion engine. 
     
     
         19 . A marine vessel comprising a marine propulsion unit of  claim 1 . 
     
     
         20 . A method for pitching a pitchable propeller of a marine propulsion unit of  claim 1 , comprising
 providing at least one motor for rotating a pitchable propeller around an axis,   connecting a first power way with the motor and a first shaft,   connecting a second power way with the motor or another motor and a second shaft,   controlling either the first power way or the second power way independently of each other so that a first rotation speed (rpm) of the first shaft and a second rotation speed (rpm) of the second shaft can vary,   arranging a coupling between the first shaft, the second shaft and the pitchable propeller,   adjusting a pitch angle of the pitchable propeller by varying the first rotation speed and/or second rotation speed in relation to the other.