Patent ID: 11913349
Assignee: RTX CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A turbofan engine comprising:
a fan including a plurality of fan blades, and an outer housing surrounding the fan to define a bypass flow path;
a low fan pressure ratio of less than 1.45 measured across the plurality of fan blades alone at a cruise condition at 0.8 Mach and 35,000 feet;
a compressor section including a first compressor and a second compressor;
a turbine section including a fan drive turbine and a second turbine, wherein the fan drive turbine includes three stages, the second turbine drives the second compressor, and the second turbine includes two stages;
an epicyclic gear system with a gear reduction and a gear reduction ratio of greater than 2.5:1, the fan drive turbine driving the fan through the epicyclic gear system, and the epicyclic gear system is straddle-mounted by first and second bearings on opposite sides of the gear reduction relative to an engine longitudinal axis;
a fan drive shaft interconnecting the epicyclic gear system and the fan;
wherein the fan drive turbine has a first exit area at a first exit point and is rotatable at a first speed, the second turbine has a second exit area at a second exit point and is rotatable at a second speed, the second speed being greater than twice the first speed;
wherein a first performance quantity is defined as the product of the first speed squared and the first exit area, a second performance quantity is defined as the product of the second speed squared and the second exit area, and a performance ratio of the first performance quantity to the second performance quantity is between 0.8 and 1.5;
wherein the gear system includes a sun gear, a plurality of intermediate gears surrounding the sun gear, and a ring gear surrounding the plurality of intermediate gears;
wherein the gear system is a planetary gear system including a carrier that supports the plurality of intermediate gears, the first bearing supports the fan drive shaft, the fan drive shaft interconnects the carrier and the fan, and the second bearing supports an aft portion of the carrier; and
wherein the second bearing is axially aligned with the carrier relative to the engine longitudinal axis, and the second bearing is situated along an outer periphery of the carrier.