Marine propulsion device

摘要

A crankshaft includes a coupling portion, a first functional portion, and a second functional portion. The coupling portion is coupled to a connecting rod. The first functional portion is provided on an upper portion of the crankshaft protruding from a crankcase. The first functional portion drives a first functional component. The second functional portion is provided on a lower portion of the crankshaft protruding from the crankcase. The second functional portion drives a second functional component. The entire crankshaft has been processed by a first treatment to at least enhance the corrosion resistance thereof. At least a coupling portion of the crankshaft has been processed by a second treatment to at least enhance the strength thereof. Neither of the first functional portion and the second functional portion has been processed by the second treatment.

主权项

1. A marine propulsion device comprising:
an engine cover; an engine disposed within the engine cover; a drive shaft disposed below the engine and along a vertical plane; and a propeller shaft connected to the drive shaft in a power transmittable state; wherein the engine includes:
a cylinder;a piston configured to slide inside the cylinder;a connecting rod coupled to the piston, the connecting rod configured to convert a reciprocating motion of the piston into a rotary motion;a crankshaft coupled to the connecting rod, the crankshaft connected to the drive shaft in a power transmittable state; anda crankcase accommodating a portion of the crankshaft, an upper portion of the crankshaft and a lower portion of the crankshaft protruding outwardly from the crankcase; the crankshaft includes:
a coupling portion coupled to the connecting rod;a first functional portion provided on the upper portion of the crankshaft protruding from the crankcase, the first functional portion arranged to drive a first functional component; anda second functional portion provided on the lower portion of the crankshaft protruding from the crankcase, the second functional portion arranged to drive a second functional component; the entire crankshaft has been processed by a first treatment to at least enhance a corrosion resistance thereof; at least an entire surface of the coupling portion of the crankshaft has been processed by a second treatment to at least enhance a strength thereof; and neither of the first functional portion and the second functional portion has been processed by the second treatment.