Reduction gears

The reduction gearbox is a freestanding gearbox intended for integrated propulsion systems. It is designed
as a combined speed reduction unit with common hydraulic system for gear and propeller.

Reduction GearThe Rolls-Royce gearbox range is based on the single-input single-output design with built-in clutch and thrustblock - and a wide variety of power-take-offs that enable large-shaft generators to be driven - and electric motors to feed power for get-you-home propulsion or as part of a hybrid propulsion system.

The input shaft is provided with keyway for mounting of the flexible coupling and the output shaft with a cylindrical shaft or flange.

The power, torque and shaft offsets correspond to the current and anticipated market requirements in terms of engine power, speed, and propeller revs to suit a wide variety of offshore, merchant and fishing vessels.

Type or model numbering represents the shaft offset in millimetres, whether vertical, or horizontal to port or starboard. Models 480-1080 are available to give a torque range from 90 to 1,200kNm.

Large reduction ratios are a particular design feature, that accommodate all the popular medium-speed engines and permit low efficient propeller speeds to the extent that the hull lines allow.

They are normally equipped with one-step reductions from 1:51 to 6.3. Some applications can be delivered with two-step reduction with maximum ratio up to 12:1.

When a Rolls-Royce reduction gear is supplied with a Rolls-Royce controllable pitch propeller shaftline, an integrated oil distribution box and hydraulics is also included.

Typical applications:

  • Offshore supply vessels
  • Fishing vessels
  • Ferries
  • Tugs
  • Cargo vessels

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