Transfer bearing for geared turbofan
A gear reduction for a gas turbine engine comprises a carrier driven to rotate gears. The gears are supported by journal bearings. The carrier extends through a transfer bearing, which provides oil to passages within the carrier to supply oil to the gears and to the journal bearings. A device limits leakage oil from the transfer bearing to axial ends of the transfer bearing to a controlled amount. A gas turbine engine is also disclosed.
1. A gear reduction for a gas turbine engine comprising:
a carrier driven and rotating with gears, said gears being supported by journal bearings;
said carrier extending through a transfer bearing, said transfer bearing being static and providing oil to passages within said carrier to supply oil to said gears and to said journal bearings; and
a device to limit leakage oil from said transfer bearing to axial ends of said transfer bearing to a controlled, non-zero, amount.
2. The gear reduction as set forth in claim 1 , wherein said device to limit leakage oil includes a supply of pressurized air to said ends.
3. The gear reduction as set forth in claim 2 , wherein said device to limit leakage oil includes a labyrinth seal at each axial end of said transfer bearing, with said pressurized air supplied on an opposed side of said labyrinth seal from said axial ends.
4. The gear reduction as set forth in claim 2 , wherein said device to limit leakage oil also includes piston ring seals.
5. The gear reduction as set forth in claim 2 , wherein said device to limit leakage oil also includes a carbon gap seal providing a controlled leakage gap between an inner periphery of said carbon gap seal and an outer periphery of said carrier.
6. The gear reduction as set forth in claim 1 , wherein said device to limit leakage includes piston ring seals.
7. The gear reduction as set forth in claim 1 , wherein said device to limit leakage includes a carbon gap seal providing a controlled leakage gap between an inner periphery of said carbon gap seal and an outer periphery of said carrier.
8. The gear reduction as set forth in claim 7 , wherein said gears are planet gears.
9. The gear reduction as set forth in claim 8 , wherein a gear ratio of said gear reduction is greater than or equal to 2.3.
10. The gear reduction as set forth in claim 1 , wherein said gears are planet gears.
11. The gear reduction as set forth in claim 10 , wherein a gear ratio of said gear reduction is greater than or equal to 2.3.
12. The gear reduction as set forth in claim 1 , wherein a gear ratio of said gear reduction is greater than or equal to 2.3.
13. A gas turbine engine comprising:
a fan drive turbine driving a fan rotor through a gear reduction;
the gear reduction including a carrier driven and rotating with gears, said gears being supported by journal bearings; and
said carrier extending through a transfer bearing, said transfer bearing being static and providing oil to passages within said carrier to supply oil to said gears and to said journal bearings, and a device to limit leakage oil from said transfer bearing to axial ends of said transfer bearing to a controlled, non-zero, amount.
14. The gas turbine engine as set forth in claim 13 , wherein said device to limit leakage oil includes a supply of pressurized air to said ends.
15. The gas turbine engine as set forth in claim 13 , wherein said device to limit leakage oil includes a labyrinth seal at each axial end of said transfer bearing.
16. The gas turbine engine set forth in claim 13 , wherein said device to limit leakage oil also includes piston ring seals.
17. The gas turbine engine as set forth in claim 13 , wherein said device to limit leakage oil also includes a carbon gap seal providing a controlled leakage gap between an inner periphery of said carbon gap seal and an outer periphery of said carrier.
18. The gas turbine engine as set forth in claim 13 , wherein the fan drive turbine also driving a compressor, with said gear reduction being placed between said compressor and said fan rotor.
19. The gas turbine engine as set forth in claim 13 , wherein a gear ratio of the gear reduction is greater than or equal to 2.3.
20. The gas turbine engine as set forth in claim 19 , wherein said fan rotor delivering air into a bypass duct and into a compressor, and a bypass ratio being greater than or equal to 10.0.
21. The gas turbine engine as set forth in claim 20 , further comprising a fan section comprising the fan rotor, with a low fan pressure ratio of less than 1.45, the low fan pressure ratio measured across a fan blade alone.
22. The gas turbine engine as set forth in claim 21 , wherein the fan drive turbine includes an inlet, an outlet and a pressure ratio of greater than 5, wherein the pressure ratio is a ratio of pressure measured prior to the inlet as related to a pressure at the outlet prior to an exhaust nozzle.
23. The gas turbine engine as set forth in claim 13 , wherein said fan rotor delivering air into a bypass duct and into a compressor, and a bypass ratio being greater than or equal to 10.0.
24. The gas turbine engine as set forth in claim 23 , further comprising a fan section comprising the fan rotor, with a low fan pressure ratio of less than 1.45, the low fan pressure ratio measured across a fan blade alone.
25. The gas turbine engine as set forth in claim 24 , wherein the fan drive turbine includes an inlet, an outlet and a pressure ratio of greater than 5, wherein the pressure ratio is a ratio of pressure measured prior to the inlet as related to a pressure at the outlet prior to an exhaust nozzle.
26. The gas turbine engine as set forth in claim 13 , further comprising a fan section comprising the fan rotor, with a low fan pressure ratio of less than 1.45, the low fan pressure ratio measured across a fan blade alone.
27. The gas turbine engine as set forth in claim 13 , wherein the fan drive turbine includes an inlet, an outlet and a pressure ratio of greater than 5, wherein the pressure ratio is a ratio of pressure measured prior to the inlet as related to a pressure at the outlet prior to an exhaust nozzle.
28. A gas turbine engine comprising:
a fan drive turbine driving a fan rotor through a gear reduction;
the gear reduction including a carrier driven and rotating with gears, said gears being supported by journal bearings; and
said carrier extending through a transfer bearing, said transfer bearing providing oil to passages within said carrier to supply oil to said gears and to said journal bearings, and a device to limit leakage oil from said transfer bearing to axial ends of said transfer bearing to a controlled, non-zero, amount.
29. The gas turbine engine as set forth in claim 28 , wherein a gear ratio of the gear reduction is greater than or equal to 2.3.
30. The gas turbine engine as set forth in claim 29 , wherein said fan rotor delivering air into a bypass duct and into a compressor, and a bypass ratio being greater than or equal to 10.0.