System for braking a low pressure spool in a gas turbine engine
AssigneePratt & Whitney Canada Corp.
InventorsPatrick Gates, Olivier Bibor
Life of this patent
Estimating the term…
Abstract
A braking system for the low pressure spool of a gas turbine engine includes a braking assembly connected to the low pressure spool and reversibly configurable between an actuated state and an unactuated state. The braking assembly in the unactuated state allows rotation of the low pressure spool without interference. The braking assembly in the actuated state applies a force opposing the rotation of the low pressure spool. A method of controlling the speed of rotation of a low pressure spool and a method of controlling the speed of rotation of low and high pressure spools are also discussed.
Claims20
A gas turbine engine comprising:
- a low pressure spool and a high pressure spool rotating independently from one another;
- a reduction gearbox connected to a low pressure shaft of the low pressure spool for transmitting a speed of rotation to an output shaft or a propeller shaft;
- and
- a braking assembly connected to the low pressure spool by being directly connected to a gear of the reduction gearbox, the braking assembly being reversibly configurable between an actuated state and an unactuated state, the braking assembly in the unactuated state allowing rotation of the low pressure spool without interference between the braking assembly and the low pressure spool,
- wherein the braking assembly includes a movable plate movable to frictionally engage a pad connected to the low pressure spool when the braking assembly is in the actuated state, the plate being disposed away from the pad when the braking assembly is in the unactuated state, and/or
- wherein the braking assembly includes a static plate disposed in proximity of, spaced apart from and parallel with a surface of a web of the gear of the gearbox, a fluid being injected between the static plate and the surface when the braking assembly is in the actuated state,
- the braking assembly in the actuated state applying a hydraulic friction force directly on the web of the gear and/or a friction force on the low pressure spool, the hydraulic friction force and/or the friction force opposing the rotation of the low pressure spool, the braking assembly being operatively disengaged from the high pressure spool in both of the actuated state and the unactuated state.
A method of controlling a speed of rotation of a low pressure spool in a gas turbine engine, the method comprising:
- rotating the low pressure spool independently of a high pressure spool of the gas turbine engine;
- determining if at least one parameter indicative of the speed of rotation of the low pressure spool has crossed at least one predetermined threshold value;
- if the at least one parameter has crossed the predetermined threshold value, actuating a braking assembly by delivering fluid between a static plate and a surface of a web of a gear of a reduction gearbox connected to a low pressure shaft of the low pressure spool to apply a hydraulic friction force directly to the web of the gear of the reduction gearbox and/or by moving a non-rotating plate to frictionally engage a pad connected to the low pressure spool to create a friction force on the low pressure spool, the hydraulic friction force and/or the friction force opposing the rotation of the low pressure spool, the low pressure spool rotating independently of the high pressure spool independently of the force being applied.
A method of controlling a speed of rotation of low and high pressure spools in a gas turbine engine, the method comprising:
- maintaining the speed of rotation of the high pressure spool above a second threshold value by controlling a fuel flow of the gas turbine engine;
- and
- maintaining the speed of rotation of the low pressure spool below a first threshold value by selectively applying a hydraulic friction force directly on a web of a gear of a reduction gearbox connected to a low pressure shaft of the low pressure spool by delivering fluid between a static plate and a surface of the web and/or applying a friction force on the low pressure spool by moving a non-rotating plate to frictionally engage a pad connected to the low pressure spool, while the low pressure spool rotates independently of the high pressure spool, the low pressure spool rotating independently of the high pressure spool independently of the force being applied.
Dependencies are inferred from the claim text.