Journal bearing for rotating gear carrier

• US 10,443,708 B2
• Filed: 04/19/2016
• Issued: 10/15/2019
• Est. Priority Date: 06/23/2015
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Sheridan, William G.
• Primary Examiner(s): Bogue, Jesse S
• Application Number:
  US15/132,620
• Publication Number:
  US 20160377166A1
• Time in Patent Office: 1,274 Days
• CPC Class Codes: F01D 25/162 Bearing supports
• CPC Class Codes: F01D 25/166 Sliding contact bearing gas bearings F01D25/22
• CPC Class Codes: F02C 3/107 with two or more rotors connected by power transmission
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F05D 2240/53 Hydrodynamic or hydrostatic bearings
• CPC Class Codes: F05D 2240/54 Radial bearings
• CPC Class Codes: F05D 2250/241 spherical
• CPC Class Codes: F05D 2260/40311 of the epicyclical, planetary or differential type
• CPC Class Codes: F05D 2260/98 Lubrication
• CPC Class Codes: F16H 1/28 with gears having orbital motion
• CPC Class Codes: F16H 2057/085 Bearings for orbital gears
• CPC Class Codes: F16H 57/043 within rotary parts, e.g. axial channels or radial openings in shafts
• CPC Class Codes: F16H 57/0471 Bearing
• CPC Class Codes: F16H 57/0479 Gears or bearings on planet carriers
• CPC Class Codes: F16H 57/0486 with fixed gear ratio differentials F16H57/0483
• CPC Class Codes: F16H 57/082 Planet carriers
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A gear system for a geared turbofan engine includes a sun gear, a planet gear supported in a carrier and engaged to the sun gear, a forward journal bearing and an aft journal bearing both supporting the planet gear. The carrier includes a forward wall supporting the forward journal bearing and an aft wall supporting the aft journal bearing. A ring gear is engaged to the planet gear. A geared turbofan engine is also disclosed.

Claims

1. A gear system for a geared turbofan engine comprising:

a sun gear;

a carrier including a forward wall and an aft wall;

a planet gear supported in the carrier and engaged to the sun gear, the planet gear including gear section disposed between a forward end and an aft end and an open inner cavity extending through the planet gear from the forward end to the aft end;

a forward journal bearing disposed about an outer surface of the forward end of the planet gear and an aft journal bearing disposed about an outer surface of the aft end of the planet gear, wherein the forward journal bearing supports the forward end of the planet gear within the forward wall of the carrier and the aft journal bearing supports the aft end of the planet gear within the aft wall of the carrier, and wherein the aft journal bearing and the forward journal bearing each have a cylindrical inner surface fit to the corresponding forward end and aft end of the planet gear, an outer partially spherical surface and an oil feed opening; and

a ring gear engaged to the planet gear.

2. The gear system as recited in claim 1, wherein one of the carrier and the ring gear is fixed.

3. The gear system as recited in claim 1, wherein the carrier is fixed and the ring gear rotates.

4. The gear system as recited in claim 1, wherein each of the aft journal bearing and the forward journal bearing includes an anti-rotation pin engaged to the corresponding one of the forward wall and aft wall of the carrier.

5. The gear system as recited in claim 4, wherein the carrier includes passages in communication with the oil feed opening for providing lubricant to each of the forward journal bearing and the aft journal bearing.

6. The gear system as recited in claim 4, wherein the oil feed opening and the anti-rotation pin are spaced at least 90 degrees apart.

7. The gear system as recited in claim 1, wherein the planet gear includes an internal cavity.

8. The gear system as recited in claim 1, wherein the forward end and the aft end each include a wall with a rim thickness that is less than two times a height of gear teeth in the gear section.

9. The gear system as recited in claim 1, wherein the forward journal bearing and the aft journal bearing include a portion of at least one of a bronze material, a bronze coating, a bronze alloy and a copper-lead alloy.

10. A geared turbofan engine 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 section; and

a gear system driven by the turbine section, the gear system including a sun gear, a planet gear supported in a carrier and engaged to the sun gear;

a forward journal bearing and an aft journal bearing both supporting the planet gear, the carrier including a forward wall supporting the forward journal bearing and an aft wall supporting the aft journal bearing and a ring gear engaged to the planet gear, wherein the planet gear includes an open inner cavity extending through from a forward end to an aft end of the planet ear with the forward journal bearing disposed about an outer surface at the forward end and the aft journal bearing disposed about an outer surface at the aft end and each of the aft journal bearing and the forward journal bearing have an inner cylindrical surface fit to an outer surface of a corresponding forward end and aft end of the planet gear, an outer partially spherical surface and an oil feed opening.

11. The geared turbofan engine as recited in claim 10, wherein the carrier rotates and drives the fan and the ring gear is fixed.

12. The geared turbofan engine as recited in claim 10, wherein the carrier is fixed and the ring gear rotates to drive the fan.

13. The geared turbofan engine as recited in claim 10, wherein each of the aft journal bearing and the forward journal bearing includes an anti-rotation pin engaged to the corresponding one of the forward wall and aft wall of the carrier.

14. The geared turbofan engine as recited in claim 13, wherein the carrier includes passages in communication with the oil feed opening for providing lubricant to each of the forward journal bearing and the aft journal bearing.

15. The geared turbofan engine gear system as recited in claim 10, wherein the planet gear includes an internal cavity.

16. The geared turbofan engine as recited in claim 10, wherein the planet gear includes a gear section disposed between the forward end and the aft end, the gear section having gear teeth and each of the forward end and the aft end include a wall with a rim thickness less than two times a height of gear teeth in the gear section.

17. The geared turbofan engine as recited in claim 10, wherein the forward journal bearing and the aft journal bearing include at least a portion of at least one of a bronze material, a bronze coating, a bronze alloy and a copper-lead alloy.

18. The geared turbofan as recited in claim 13, wherein the oil feed opening and the anti-rotation pin are spaced at least 90 degrees apart.