Vessel propulsion apparatus, vessel, auxiliary machine-equipped engine, and torque fluctuation absorber

An auxiliary machine-equipped engine comprising:

• an engine including a crank shaft;
• an auxiliary machine including an input shaft;
• a gear train including a plurality of gears to transmit a driving force from the crank shaft to the auxiliary machine;
• and
• a torque fluctuation absorber to absorb a fluctuation in torque transmitted to the gear train, the torque fluctuation absorber including:
• a first outer helical spline rotatable integrally with a torque transmission shaft that includes at least one of the crank shaft, the input shaft, and an intermediate shaft located in a torque transmission path from the crank shaft to the input shaft;
• an intermediate member that coaxially surrounds the torque transmission shaft and is able to move in a first axial direction and in a second axial direction opposite to the first axial direction, the intermediate member including a first inner helical spline on an inner circumference thereof and a second outer helical spline on an outer circumference thereof, the first inner helical spline being engaged with the first outer helical spline to provide a first helical spline coupling;
• an outer member that coaxially surrounds the torque transmission shaft and is regulated in axial movement with respect to the torque transmission shaft, the outer member including teeth on an outer circumference thereof and a second inner helical spline on an inner circumference thereof, the teeth being meshed with corresponding gears of the gear train, the second inner helical spline being engaged with the second outer helical spline to provide a second helical spline coupling;
• a first spring to bias the intermediate member in the first axial direction;
• and
• a second spring to bias the intermediate member in the second axial direction.

A torque fluctuation absorber to absorb a fluctuation in torque transmitted to a gear train including a plurality of gears, the torque fluctuation absorber comprising:

• a first outer helical spline rotatable integrally with a torque transmission shaft;
• an intermediate member that coaxially surrounds the torque transmission shaft and is able to move in a first axial direction and in a second axial direction opposite to the first axial direction, the intermediate member including a first inner helical spline on an inner circumference thereof and a second outer helical spline on an outer circumference thereof, the first inner helical spline being engaged with the first outer helical spline to provide a first helical spline coupling;
• an outer member that coaxially surrounds the torque transmission shaft and is regulated in axial movement with respect to the torque transmission shaft, the outer member including teeth on an outer circumference thereof and a second inner helical spline on an inner circumference thereof, the teeth being meshed with corresponding gears of the gear train, the second inner helical spline being engaged with the second outer helical spline to provide a second helical spline coupling;
• a first spring to bias the intermediate member in the first axial direction;
• and
• a second spring to bias the intermediate member in the second axial direction.