Ship propulsion machine

Abstract

A ship propulsion machine includes: a power unit; a propeller; and a drive shaft. The power unit includes: a first motor including a first motor shaft; a second motor including a second motor shaft; and a power switching device configured to switch a mode between a mode in which the first motor shaft and the second motor shaft are connected and a mode in which the first motor shaft and the second motor shaft are disconnected. The first motor and the second motor are arranged in an upper portion of the ship propulsion machine, the first motor shaft, the second motor shaft, and the drive shaft extend vertically, the second motor is arranged above the first motor, an upper portion of the drive shaft is connected to the first motor shaft, and the power switching device is arranged between the first motor and the second motor.

What is claimed is: 
     
         1 . A ship propulsion machine comprising:
 a power unit configured to generate power;   a propeller; and   a drive shaft configured to transmit the power generated by the power unit to the propeller,   wherein the power unit comprises:
 a first motor comprising a first motor shaft; 
 a second motor comprising a second motor shaft; and 
 a power switching device configured to disconnectably connect the first motor shaft and the second motor shaft to each other, and to switch a mode between a first mode in which the first motor shaft and the second motor shaft are connected to each other and a second mode in which the first motor shaft and the second motor shaft are disconnected from each other, 
   wherein the first motor and the second motor are arranged in an upper portion of the ship propulsion machine,   wherein each of the first motor shaft, the second motor shaft, and the drive shaft extends vertically,   wherein the second motor is arranged above the first motor,   wherein an upper portion of the drive shaft is connected to the first motor shaft, and   wherein the power switching device is arranged between the first motor and the second motor.   
     
     
         2 . The ship propulsion machine according to  claim 1 ,
 wherein the power switching device comprises a connecting member provided to be movable between the first motor and the second motor in a vertical direction, and   wherein the connecting member is configured to connect an upper end portion of the first motor shaft and a lower end portion of the second motor shaft to each other in response to the connecting member moving in one direction in the vertical direction, and to disconnect the upper end portion of the first motor shaft and the lower end portion of the second motor shaft from each other in response to the connecting member moving in the other direction in the vertical direction.   
     
     
         3 . The ship propulsion machine according to  claim 2 ,
 wherein the first motor shaft and the second motor shaft are arranged coaxially with each other,   wherein the connecting member is a shaft provided between the upper end portion of the first motor shaft and the lower end portion of the second motor shaft so as to be coaxial with the first motor shaft and the second motor shaft, the shaft being provided to be movable vertically,   wherein an upper end portion of the connecting member is provided with a coupling portion configured to couple the connecting member with the lower end portion of the second motor shaft such that the connecting member is not allowed to rotate with respect to the second motor shaft but is allowed to move vertically with respect to the second motor shaft,   wherein a lower end portion of the connecting member is provided with a fitting portion configured to fit with a fitted portion provided at the upper end portion of the first motor shaft, and   wherein the connecting member is configured to connect, in response to the connecting member moving downward, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft to each other by allowing the fitting portion to fit with the fitted portion while the coupling portion remains coupled with the lower end portion of the second motor shaft, and to disconnect, in response to the connecting member moving upward, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft from each other by releasing a fitting between the fitting portion and the fitted portion.   
     
     
         4 . The ship propulsion machine according to  claim 2 ,
 wherein the first motor shaft and the second motor shaft are arranged coaxially with each other,   wherein the connecting member is a shaft provided between the upper end portion of the first motor shaft and the lower end portion of the second motor shaft so as to be coaxial with the first motor shaft and the second motor shaft, the shaft being provided to be movable vertically,   wherein a lower end portion of the connecting member is provided with a coupling portion configured to couple the connecting member with the upper end portion of the first motor shaft such that the connecting member is not allowed to rotate with respect to the first motor shaft but is allowed to move vertically with respect to the first motor shaft,   wherein an upper end portion of the connecting member is provided with a fitting portion configured to fit with a fitted portion provided at the lower end portion of the second motor shaft, and   wherein the connecting member is configured to connect, in response to the connecting member moving upward, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft to each other by allowing the fitting portion to fit with the fitted portion while the coupling portion remains coupled with the upper end portion of the first motor shaft, and to disconnect, in response to the connecting member moving downward, the upper end portion of the first motor shaft and the lower end portion of the second motor shaft from each other by releasing a fitting between the fitting portion and the fitted portion.