Patent attributes
In an outboard marine motor including an upper case (4) enclosing an engine (E) and a lower case (5) fitted with a propeller (12) and connected to a lower end of the upper case, the lower case is configured to be turned relative to the upper case around a vertical axial line which is coaxial with a vertical drive shaft (10) that transmit torque of the engine to the propeller. Thereby, the outboard marine motor can be steered simply by turning the lower case. Because the upper case having a relatively large lateral dimension as compared with the lower case is not required to be turned, a large steering angle can be achieved without the outboard marine motor interfering with watercraft having the outboard marine motor mounted thereon. In particular, the lower case is turned by an actuator including an electric motor and a worm gear mechanism (50) for transmitting an output torque of the electric motor to the lower case so that a high speed reduction ratio can be achieved by using a highly compact structure.
