🔍 Key Concepts

• Function of a quill shaft in a turbine reduction gear system • Difference between torsional flexibility/rigidity and radial or axial alignment • What machinery actually handles axial thrust in a gear/turbine train (think thrust bearings)

💭 Think About

• Look at how the quill shaft is shaped in the illustration: long, relatively small diameter, supported at the ends. What kind of loads is that design best suited to handle—torsion, radial bending, or axial thrust? • Ask yourself which components in a typical marine reduction gear are responsible for taking axial thrust from the gears and for correcting misalignment between shafts. • Consider whether the quill shaft is intended to move axially, or mainly to transmit torque while allowing a certain behavior in twist.

✅ Before You Answer

• Verify which part of the train (thrust bearing, flexible coupling, quill shaft) normally absorbs axial thrust from the gears. • Decide whether a quill shaft is usually designed to compensate for radial misalignment or instead to influence torsional behavior (twist) of the gear train. • Check if the quill shaft’s main role is to permit axial movement between gears or to control how torque is transmitted between turbine and gear train.