Outboard motor

An outboard motor comprising:

• an upper case configured to be supported on a hull;
• a lower case supported on a lower portion of the upper case to be pivotable about a first axis that extends vertically;
• a first drive source disposed within the upper case;
• an upper drive shaft that is rotatably supported by the upper case and extends along the first axis to be connected to an output shaft of the first drive source at an upper end thereof;
• a planetary gear mechanism disposed along the first axis inside the upper case or the lower case and connected to a lower end of the upper drive shaft;
• a lower drive shaft that is rotatably supported by the lower case, extends along the first axis to be connected to the planetary gear mechanism at an upper end thereof via a synchronization mechanism, and is provided with a first bevel gear at a lower end thereof;
• a propeller shaft that is rotatably supported by the lower case, extends in a direction perpendicular to the first axis, is provided at one end thereof with a second bevel gear engaging with the first bevel gear, and is provided with a propeller at another end thereof that protrudes out from the lower case;
• and
• a second drive source that provides the lower case with a torque about the first axis,
• wherein the planetary gear mechanism includes a first sun gear, a planetary carrier that rotatably supports multiple first planetary gears engaging with the first sun gear, multiple second planetary gears provided to be coaxial with the respective first planetary gears and to rotate integrally with the respective first planetary gears, and multiple third planetary gears respectively engaging with the second planetary gears, an internal gear engaging with the multiple first planetary gears, and a second sun gear disposed to be coaxial with the first sun gear and engaging with the multiple third planetary gears,
• the first sun gear is connected to the lower end of the upper drive shaft,
• the internal gear is connected to the lower case so as to provide the lower case with a torque in a direction opposite to a rotation direction of the lower drive shaft, and
• the synchronization mechanism is capable of taking a first state to connect the planetary carrier to the lower drive shaft and a second state to connect the second sun gear to the lower drive shaft.