Bimetallic shaft for gearbox systems to limit wear and corrosion

A gearbox comprising:

• a gearbox housing;
• a gearbox shaft comprising a joint that permanently affixes a first distal end of a first shaft member to a second proximate end of a second shaft member such that the first shaft member is axially aligned with the second shaft member, the first distal end substantially abuts the second proximate end, and a first diameter of the first shaft member is substantially identical to a second diameter of the second shaft member, and wherein the first shaft member and the second shaft member are formed from different materials;
• and
• a gearbox shaft seal that surrounds the gearbox shaft radially on a portion of the gearbox shaft having a sealing diameter that is substantially identical to the first diameter to provide a barrier between a first environment inside the gearbox housing and a second environment outside the gearbox housing, wherein the first shaft member is isolated from the second environment.

A rotorcraft comprising:

• an engine;
• and
• a gearbox mechanically coupled to a rotor, propeller or a proprotor of the rotorcraft, the gearbox comprising:
• a gearbox housing;
• a gearbox shaft comprising a joint that permanently affixes a first distal end of a first shaft member to a second proximate end of a second shaft member such that the first shaft member is axially aligned with the second shaft member, the second shaft member mechanically coupled to the engine, the first distal end substantially abuts the second proximate end, and a first diameter of the first shaft member is substantially identical to a second diameter of the second shaft member, and wherein the first shaft member and the second shaft member are formed from different materials;
• and
• a gearbox shaft seal that surrounds the gearbox shaft radially on a portion of the gearbox shaft having a sealing diameter that is substantially identical to the first diameter to provide a barrier between a first environment inside the gearbox housing and a second environment outside the gearbox housing, wherein the first shaft member is isolated from the second environment.