Gearboxes for aircraft gas turbine engines
AssigneeROLLS-ROYCE plc
InventorMark SPRUCE
Life of this patent
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Abstract
Gearboxes for aircraft gas turbine engines, in particular to arrangements for journal bearings such gearboxes, and to related methods of operating such gearboxes and gas turbine engines. Example embodiments include a gearbox for an aircraft gas turbine engine, the gearbox including: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.
Claims20
A gas turbine engine for an aircraft, comprising:
- an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
- a fan located upstream of the engine core, the fan comprising a plurality of fan blades;
- and
- a gearbox configured to receive an input from the core shaft and provide an output drive to the fan so as to drive the fan at a lower rotational speed than the core shaft, the gearbox comprising:
- a sun gear;
- a plurality of planet gears surrounding and engaged with the sun gear;
- and
- a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin,
- wherein:
- a ratio of a length, L, of the internal and external sliding surfaces to a diameter, D, of each journal bearing is greater than 0.5;
- a pitch circle diameter of the ring gear is no greater than 1200 mm;
- and
- a diametral clearance of each journal bearing, defined by the difference between the diameter of the internal sliding on the planet gear and the diameter of the external sliding surface on the pin, is between around 120 m and around 600 m.
The gas turbine engine according to 5, wherein the surface coating comprises a third layer positioned such that the second layer is between the first layer and the third layer.
A gas turbine engine for an aircraft, comprising:
- an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
- a fan located upstream of the engine core, the fan comprising a plurality of fan blades;
- and
- a gearbox configured to receive an input from the core shaft and provide an output drive to the fan so as to drive the fan at a lower rotational speed than the core shaft, the gearbox comprising:
- a sun gear;
- a plurality of planet gears surrounding and engaged with the sun gear;
- and
- a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin,
- wherein:
- a ratio of a length, L, of the internal and external sliding surfaces to a diameter, D, of each journal bearing is greater than 0.5;
- a pitch circle diameter of the ring gear is no greater than 1200 mm;
- and
- a diameter of each journal bearing is between around 120 mm and 200 mm.
A gas turbine engine for an aircraft, comprising:
- an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
- a fan located upstream of the engine core, the fan comprising a plurality of fan blades;
- and
- a gearbox configured to receive an input from the core shaft and provide an output drive to the fan so as to drive the fan at a lower rotational speed than the core shaft, the gearbox comprising:
- a sun gear;
- a plurality of planet gears surrounding and engaged with the sun gear;
- and
- a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin,
- wherein:
- a ratio of a length, L, of the internal and external sliding surfaces to a diameter, D, of each journal bearing is greater than 0.5;
- a pitch circle diameter of the ring gear is no greater than 1200 mm;
- and
- the internal or external surface of the journal bearing has a surface coating.
Dependencies are inferred from the claim text.