| 摘要 |
PROBLEM TO BE SOLVED: To provide a boat propulsion unit for improving acceleration of a marine vessel while securing efficient cooling water flow at low speed. SOLUTION: In this boat propulsion unit 1 in which rotation of a water cooling engine is transmitted to an inner shaft 5 and an outer shaft 6 through a drive shaft 22 and an advance/astern switching mechanism 40 and propellers 3, 2 coupled to the inner shaft 5 and the outer shaft 6 respectively are rotated and driven to cause required propulsion force and also a water pump 24 is driven by the drive shaft 22, a fluid coupler 25 is disposed between the water pump 24 and the advance/astern switching mechanism 40. According to the present invention, as the device is disposed at downstream side of the water pump 24 in a power transmitting path, the engine speed is transmitted to the water pump 24 without enough slip of the fluid coupler 25 on the water pump 24 to drive it and required cooling water flow can be secured at low speed when the slip causes in the fluid coupler 25. Since slip causes in rotation of the propellers 2, 3 at the beginning of acceleration and engine load is lightened, acceleration of the boat is improved. |
