Lubricant delivery system for planetary fan drive gear system
A gear system for a turbofan engine assembly includes a sun gear rotatable about an engine centerline, a non-rotatable ring gear, a rotating carrier that drives a fan, and a plurality of planet gears intermeshed between the sun gear and the ring gear. Each of the plurality of planet gears supported on rolling element bearings fit into the carrier. Each of the plurality of planet gears includes an inner cavity and a lubricant passage directed at the rolling element bearings. The carrier includes an outer scoop that receives lubricant from an outer fixed lubricant jet and feeds lubricant into the inner cavity and through the lubricant passage to spray lubricant on to the rolling element bearings. A geared turbofan engine assembly is also disclosed.
1. A gear system for a turbofan engine assembly comprising:
a sun gear rotatable about an engine centerline;
a non-rotatable ring gear;
a rotating carrier that drives a fan; and
a plurality of planet gears intermeshed between the sun gear and the ring gear, each of the plurality of planet gears supported on rolling element bearings disposed between a radially outer surface at each end of each of the plurality of planet gears and the carrier, wherein each of the plurality of planet gears includes an inner cavity and a lubricant passage directed at the rolling element bearings disposed within the carrier, the carrier including an outer scoop that receives lubricant from an outer fixed lubricant jet and feeds lubricant into the inner cavity and through the lubricant passage to spray lubricant on to the rolling element bearings and the carrier has a larger outer diameter than a pitch diameter of the ring gear.
2. The gear system as recited in claim 1 , wherein the carrier includes an inner lubricant scoop that receives lubricant from an inner fixed lubricant jet and directs lubricant through a carrier lubricant passage to at least one spray bar supported by the carrier for directing lubricant into a gear interface between one of the plurality of planet gears and one of the sun gear and the ring gear.
3. The gear system as recited in claim 2 , wherein the outer scoop includes an outer accumulator portion for holding a quantity of lubricant before entering the inner cavity.
4. The gear system as recited in claim 3 , wherein the inner scoop includes an inner accumulator portion for holding quantity of lubricant prior to entering the lubricant passage, wherein the inner accumulator portion accumulates lubricant for generating a pressure utilized to expel lubricant under pressure into the gear interface.
5. The gear system as recited in claim 4 , wherein the carrier comprises a forward plate attached to an aft plate with a fastener and the rolling element bearings are supported within an inner race and an outer race supported in each of the forward plate and the aft plate to support each of the ends of the plurality of planet gears supported by the carrier between the forward plate and the aft plate.
6. The gear system as recited in claim 5 , wherein the reduction ratio of the gear system is between 3:1 and 5:1 and the number of planet gears is at least 3.
7. The gear system as recited in claim 6 , wherein the carrier includes an opening with an inner diameter to accommodate an input shaft driving the sun gear.
8. The gear system as recited in claim 1 , wherein the rolling element bearings comprise one of a roller bearing, ball bearing, tapered roller bearing, and spherical bearing.
9. The gear system as recited in claim 1 , wherein the rolling element bearings comprise multiple rows of rolling element bearings.
10. The gear system as recited in claim 1 , wherein at least one of the ring gear and sun gear is flexibly mounted.
11. A geared turbofan engine assembly comprising:
a fan configured to drive air along a bypass flow path;
a compressor section configured to communicate compressed air to a combustor section for generating a high energy gas flow for driving a turbine section where energy is extracted and utilized to drive the compressor section and the fan; and
a gear system driven by the turbine section for driving the fan, the gear system including a sun gear rotatable about an engine centerline, a non-rotatable ring gear, a rotating carrier that drives the fan, and a plurality of planet gears intermeshed between the sun gear and the non-rotatable ring gear, the plurality of planet gears supported on rolling element bearings mounted between an outer radial surface of each of the plurality of planet gears and the carrier, each of the rolling element bearings spaced apart from an axis of rotation of a corresponding one of the plurality of planet gears, wherein each of the plurality of planet gears includes an inner cavity and a lubricant passage directed at the rolling element bearings mounted within the carrier, the carrier including an outer scoop that receives lubricant from an outer fixed lubricant jet and feeds lubricant into the inner cavity and through the lubricant passage to spray lubricant on to the rolling element bearings and the carrier has a larger outer diameter than a pitch diameter of the ring gear.
12. The geared turbofan engine assembly as recited in claim 11 , wherein the carrier includes an inner lubricant scoop that receives lubricant from an inner fixed lubricant jet and directs lubricant through a carrier lubricant passage to at least one spray bar supported by the carrier for directing lubricant into a gear interface between one of the plurality of planet gears and one of the sun gear and the ring gear.
13. The geared turbofan engine assembly as recited in claim 12 , wherein the outer scoop includes an outer accumulator portion for holding a quantity of lubricant before entering the inner cavity and the inner scoop includes an inner accumulator portion for holding a quantity of lubricant prior to entering the lubricant passage, wherein the inner accumulator portion accumulates lubricant for generating a pressure utilized to expel lubricant under pressure into the gear interface.
14. The geared turbofan engine assembly as recited in claim 13 , wherein the carrier comprises a forward plate attached to an aft plate with a fastener and the rolling element bearings are mounted within an inner race and an outer race supported in each of the forward plate and the aft plate to support each of the ends of and the plurality of planet gears supported by the carrier between the forward plate and the aft plate.
15. The geared turbofan engine assembly as recited in claim 11 , wherein the reduction ratio of the gear system is between 3:1 and 5:1 and the number of planet gears is at least 3.
16. The geared turbofan engine assembly as recited in claim 11 , wherein the rolling element bearings comprise one of a roller bearing, ball bearing, tapered roller bearing, and spherical bearing.
17. The geared turbofan engine assembly as recited in claim 11 , wherein the rolling element bearings comprise multiple rows of rolling element bearings.
18. The geared turbofan engine assembly as recited in claim 11 , wherein at least one of the ring gear and sun gear is flexibly mounted.