Gearboxes for aircraft gas turbine engines
AssigneeROLLS-ROYCE plc
InventorMark Spruce
Life of this patent
Estimating the term…
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 gearbox for an aircraft gas turbine engine, 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:
- the gearbox is of a planetary type, with the planet carrier arranged to be coupled to an output shaft, and ring gear being fixed;
- and
- during operation of the gas turbine engine at maximum take-off conditions, an operating specific load multiplied by an operating sliding speed of each journal bearing is in a range of between 450 MPa m/s and 720 MPa m/s.
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 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 that receives input from the core shaft;
- 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:
- the gearbox is of a planetary type, with the planet carrier coupled to an output shaft to drive the fan, and the ring gear being fixed;
- and
- arranged such that the sliding speed of each journal bearing is in a range of 35 m/s to 45 m/s if the gas turbine engine is operated at maximum take-off conditions.
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 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 that receives input from the core shaft;
- 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:
- the gearbox is of a planetary type, with the planet carrier coupled to an output shaft to drive the fan, and the ring gear being fixed;
- and
- arranged such that an operating specific load of each journal bearing is in a range of 10 MPa to 20 MPa if the gas turbine engine is operated at maximum take-off conditions.
Dependencies are inferred from the claim text.