Elongated journal bearing for high gear ratio epicyclic fan drive gear system
AssigneeRtx Corporation
InventorsMark A. Klein, Michael E. McCune
Life of this patent
Estimating the term…
Abstract
A fan drive gear system for a turbine engine includes a gear system with a plurality of compound intermediate gears that each include a first gear portion and a second gear portion. The second gear portion includes a forward gear portion and an aft gear portion and a ring gear assembly includes a forward ring gear that is engaged to the forward gear portion and an aft ring gear that is engaged to the aft gear portion. A carrier supports rotation of the plurality of intermediate gears with a plurality of corresponding journal bearing assemblies.
Claims20
A fan drive gear system for a turbine engine comprising:
- a sun gear configured to be driven by an engine shaft rotatable about an axis;
- a plurality of compound intermediate gears, wherein each of the plurality of intermediate gears includes a first gear portion and a second gear portion, wherein the second gear portion comprises a forward gear portion and an aft gear portion;
- a ring gear assembly including a forward ring gear engaged to the forward gear portion of each of the plurality of compound intermediate gears and an aft ring gear engaged to the aft gear portion of each of the plurality of compound intermediate gears;
- a carrier supporting rotation of the plurality of intermediate gears;
- and
- a plurality of journal bearing assemblies corresponding with the plurality of intermediate gears, wherein each of the plurality of journal bearing assemblies comprises;
- a forward portion supporting the forward gear portion of a corresponding one of the plurality of compound intermediate gears,
- an aft portion supporting the aft gear portion of a corresponding one of the plurality of compound intermediate gears,
- a middle portion,
- an outer undercut on each of the forward portion and the aft portion facing axially outward, an inner undercut on each of the forward portion and the aft portion facing axially inward toward the middle portion, and
- a ratio of a journal length to a journal diameter that is between 1.5 and 6.
(canceled)
A turbine engine assembly comprising:
- a static engine structure;
- a fan section including a plurality of blades rotatable about an axis;
- a fan drive gear system including:
- a sun gear configured to be driven by an engine shaft rotatable about the axis;
- a plurality of compound intermediate gears, wherein each of the plurality of intermediate gears includes a first gear portion and a second gear portion, wherein the second gear portion comprises a forward gear portion and an aft gear portion;
- a ring gear assembly including a forward ring gear engaged to the forward gear portion and an aft ring gear engaged to the aft gear portion, the ring gear assembly fixed to the static engine structure;
- a carrier supporting rotation of the plurality of intermediate gears, the carrier rotatable about the axis;
- and
- a plurality of journal bearing assemblies corresponding with the plurality of intermediate gears, wherein each of the plurality of journal bearing assemblies comprises a ratio of a journal length to a journal diameter that is between 1.5 and 6 and wherein each of the plurality of journal bearing assemblies includes a plurality of lubricant supply holes that are configured to communicate lubricant to an interface with an inner surface of a corresponding one of the plurality of compound intermediate gears and each of the plurality of compound intermediate gears includes an outlet for exhausting lubricant flow that is disposed between the forward gear portion and the aft gear portion;
- and
- a fan drive shaft coupled to the carrier.
Dependencies are inferred from the claim text.