Planetary gearbox for gas turbine engine

Patent metadata

Field	Value
Publication number	US-2018230902-A1
Application number	US-201715429976-A
Country	US
Kind code	A1
Filing date	Feb 10, 2017
Priority date	Feb 10, 2017
Publication date	Aug 16, 2018
Grant date	—

Abstract

In one aspect, there is provided a planetary gearbox, comprising a sun gear, a plurality of planet gear assemblies, each planet gear assembly having a main gear meshed with the sun gear, a fore lateral gear and an aft lateral gear disposed on opposite sides of the main gear and rotating therewith, a diameter of the main gear being different than a diameter of the fore and aft lateral gears, a planet carrier rotatably supporting at least some of the planet gear assemblies, and at least one fore ring gear meshed with the fore lateral gears, at least one aft ring gear meshed with the aft lateral gears, wherein one of the sun gear, the planet carrier, and the ring gears is configured to be operatively connected to an input, one is configured to be operatively connected to an output, and rotation of a remaining one is limited.

First claim

1 . A planetary gearbox, comprising:
a sun gear; a plurality of planet gear assemblies, each planet gear assembly having a main gear meshed with the sun gear, a fore lateral gear and an aft lateral gear disposed on opposite sides of the main gear and rotating therewith, a diameter of the main gear being different than a diameter of the fore and aft lateral gears; a planet carrier rotatably supporting at least some of the planet gear assemblies; and at least one fore ring gear meshed with the fore lateral gears, at least one aft ring gear meshed with the aft lateral gears, wherein one of the sun gear, the planet carrier, and the ring gears is configured to be operatively connected to an input, one is configured to be operatively connected to an output, and rotation of a remaining one is limited.

2 . The planetary gearbox according to claim 1 , wherein the diameter of the main gear is greater than the diameter of the fore and aft lateral gears.

3 . The planetary gearbox according to claim 1 , wherein a sun gear diameter is less than the diameter of the main gears of the planet gear assemblies.

4 . The planetary gearbox according to claim 1 , wherein the main gears and the sun gear are spur gears.

5 . The planetary gearbox according to claim 1 , wherein the ring gears and the aft and fore lateral gears are helical gears.

6 . The planetary gearbox according to claim 1 , wherein the planet gears assemblies are supported by shafts of the planet carrier, and bearings are disposed between the shafts and the planet gears assemblies.

7 . A gas turbine engine comprising a compressor, a combustor and a turbine, the turbine having a first section for driving the compressor and a second section driving a load, the second section of the turbine operatively connected to a sun gear of a planetary gearbox, the sun gear meshed with main gears of a plurality of planet gear assemblies pivotally mounted on a planet carrier, the planet gear assemblies each having a fore lateral gear and an aft lateral gear of a diameter different than a main gear diameter, the fore and aft lateral gears disposed on opposite sides of the main gears, at least one fore ring gear meshed with the fore lateral gears, at least one aft ring gear meshed with the aft lateral gears, one of the ring gears and the planet carrier driving the load by rotation, while rotation of another one of the ring gears and the planet carrier is limited.

8 . The gas turbine engine according to claim 7 , wherein a sun gear diameter is less than the main gear diameter.

9 . The gas turbine engine according to claim 7 , wherein the main gear diameter is greater than the diameter of the fore and aft lateral gears.

10 . The gas turbine engine according to claim 7 , wherein rotation of the ring gears is limited and the load is operatively connected to the planet carrier.

11 . The gas turbine engine according to claim 7 , wherein the load is a propeller.

12 . The gas turbine engine according to claim 7 , wherein the first section of the turbine is in driving engagement with a high-pressure section of the compressor and wherein the second section of the turbine is in driving engagement with a low-pressure section of the compressor.

13 . The gas turbine engine according to claim 12 , wherein the first section of the turbine and the high-pressure section of the compressor are mounted on a high-pressure shaft, the second section of the turbine and the low-pressure section of the compressor are mounted on a low-pressure shaft, the low-pressure shaft in driving engagement with the sun gear.

14 . A method for changing a rotational speed of a first rotating component relative to a second rotating component, comprising:
receiving a torque from the first rotating component using a sun gear; transmitting at a first rotational speed ratio a rotation of the sun gear to a plurality of main gears of a plurality of planet gear assemblies rotatably mounted onto a planet carrier; transmitting at second rotational speed ratio a rotation of the main gears to one of the planet carrier and ring gears while limiting rotation of another one of the planet carrier and the ring gears, the ring gears meshed to gears disposed on opposite sides of and rotating with the main gears; and dividing between the ring gears a load transmitted from the second rotating component.

15 . The method according to claim 14 , wherein each of the main gears has a diameter greater than a sun gear diameter, the method further comprising decreasing a rotational speed of the main gears relative to the sun gear.

16 . The method according to claim 14 , wherein a diameter of the gears disposed on the opposite sides of the main gears is less than a diameter of the main gears, the method further comprising decreasing a rotational speed of the one of the ring gears and the planet carrier relative to the gears disposed on the opposite sides of the main gears.

17 . The method of claim 14 , wherein limiting rotation comprises limiting a rotation of the ring gears.

Assignees

• Pratt & Whitney Canada

Inventors

• Desjardins Michel

Classifications

• F02C7/36 Primary

  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 title

• F02C3/107 Primary

  with two or more rotors connected by power transmission · CPC title

• F02K3/06

  with front fan · CPC title

• F05D2260/40311

  of the epicyclical, planetary or differential type · CPC title

• F16H1/28

  with gears having orbital motion · CPC title