Variable-pitch-propeller drive device and pitch-angle control method, and boat having same

A driving apparatus of a variable pitch propeller having blades, each of which has a pitch angle changeable, and a pitch adjuster for adjusting the pitch angle, wherein the pitch adjuster includes:

• blade actuating shafts that are connected to eccentric stubs coupled to lower ends of the blades and are disposed inside the propeller shaft so as to allow linear reciprocation and to push or pull the eccentric stubs;
• and
• a power converter that converts a rotating motion of the propeller shaft into a linearly reciprocating motion of the blade actuating shafts,
• wherein the power converter includes:
• guide pins that extend from outer circumferential surfaces of the blade actuating shafts and protrude through guide slots formed in an outer surface of the propeller shaft;
• and
• a guide ring that encloses an outer circumference of the propeller shaft and has a pitch deciding groove which is formed in an inner surface thereof and along which the guide pins slide.