System and method for controlling propeller pitch

Patent metadata

Field	Value
Publication number	US-10793255-B2
Application number	US-201615228148-A
Country	US
Kind code	B2
Filing date	Aug 4, 2016
Priority date	Sep 7, 2015
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

Systems and methods are disclosed for controlling the pitch angle of a propeller and rotor assembly that selectively limit the pitch angle according to a selected mode of operation. The system includes an actuator having forward and aft chambers, an oil transfer bearing (OTB), and a fine stop collar. The fine stop collar including a first passage in fluid communication with the OTB and forward chamber during a ground-based mode of operation, and a second fluid passage being in fluid communication with the OTB and forward chamber during a flight-based mode of operation.

First claim

What is claimed is:

1. A pitch control system, comprising:
a linear actuator engaged with a propeller blade crankshaft to vary propeller blade pitch, the actuator including:
a cylinder including a fluidly-sealed cylinder wall,
a piston translatably attached to the propeller blade crankshaft, the piston including a flange disposed within the cylinder to define a forward chamber and an aft chamber thereof, a projection extending from the flange through the cylinder aft chamber, and a coarse rotatable pipe attached to the piston and disposed through the cylinder forward chamber;

an oil transfer bearing (OTB) positioned along a central axis, the OTB being joined to the cylinder wall in fluid communication with the forward chamber; and
a fine stop collar annularly positioned above the OTB, the fine stop collar defining discrete first and second fluid passages, the first fluid passage being in fluid communication with the OTB and forward chamber during a ground-based mode of operation, the second fluid passage being in fluid communication with the OTB and forward chamber during a flight-based mode of operation.

2. The pitch control system of claim 1 , wherein the OTB comprises a rotatable rotor and a rotationally-fixed stator positioned about the OTB rotor, the OTB rotor being joined to the cylinder wall in parallel with the coarse rotatable pipe.

3. The pitch control system of claim 2 , wherein the OTB rotor defines at least one radial rotor hole and the OTB stator defines at least one radial stator hole fluidly communicable with the at least one radial rotor hole.

4. The pitch control system of claim 3 , wherein the OTB further comprises at least one bearing ring radially positioned between the OTB rotor and the OTB stator; and wherein the OTB stator is translationally fixed with respect to the OTB rotor.

5. The pitch control system of claim 1 , further comprising:
a cross head attached to the piston projection and including at least one finger extending radially outward therefrom; and
a crank rod extending longitudinally from the cross head finger, wherein the propeller blade crankshaft is pivotally joined to the crank rod to direct rotation of the propeller blade about a radial blade axis.

6. The pitch control system of claim 1 , wherein the fine stop collar first fluid passage is positioned parallel to the second fluid passage and axially separate therefrom; and wherein the OTB is translatably disposed through the fine stop collar and alternately communicable with the first fluid passage and the second fluid passage.

7. The pitch control system of claim 3 , wherein the at least one radial rotor hole and at least one radial stator hole have an axial range of translation between the first fluid passage and the second fluid passage, further wherein the ground-based mode of operation restricts fluid communication into the second fluid passage, and wherein the flight based mode of operation restricts fluid communication from the first fluid passage.

8. The pitch control system of claim 1 , further comprising:
a coarse inlet pipe coaxially attached to the coarse rotatable pipe in fluid communication therewith;
a ground fine inlet pipe attached to the fine stop collar in fluid communication with the first fluid passage; and
a flight fine inlet pipe attached to the fine stop collar in fluid communication with the second fluid passage.

9. The pitch control system of claim 8 , wherein the projection of the piston defines at least one orifice through which the coarse rotatable pipe and the aft chamber are in fluid communication.

10. A gas turbine engine, comprising:
a core engine extending along a central axis;
at least one row of propeller blades mounted circumferentially about the central axis, including at least one propeller blade and crankshaft pivotable about a radial blade axis;
a linear actuator positioned parallel to the central axis and including:
a cylinder including a fluidly-sealed cylinder wall,
a piston translatably attached to the propeller blade crankshaft, the piston including a flange disposed within the cylinder to define a forward chamber and an aft chamber thereof, a projection extending from the flange through the cylinder aft chamber, and a coarse rotatable pipe attached to the piston and disposed through the forward chamber;

an oil transfer bearing (OTB) positioned along the central axis, the OTB being joined to the cylinder wall in fluid communication with the forward chamber; and
a fine stop collar annularly positioned above the OTB, the fine stop collar defining discrete first and second fluid passages, the first fluid passage being in fluid communication with the OTB and forward chamber during a ground-based mode of operation, the second fluid passage being in fluid communication with the OTB and forward chamber during a flight-based mode of operation.

11. The gas turbine engine of claim 10 , wherein the OTB comprises a rotatable rotor and a rotationally-fixed stator positioned about the OTB rotor, the OTB rotor being joined to the cylinder wall in parallel with the coarse rotatable pipe.

12. The gas turbine engine of claim 11 , wherein the OTB rotor defines at least one radial rotor hole and the OTB stator defines at least one radial stator hole fluidly communicable with the at least one radial rotor hole.

13. The gas turbine engine of claim 12 , wherein the OTB further comprises at least one bearing ring radially positioned between the OTB rotor and the OTB stator; and wherein the OTB stator is translationally fixed with respect to the OTB rotor.

14. The gas turbine engine of claim 10 , further comprising:
a cross head attached to the piston projection and including at least one finger extending radially outward therefrom; and
a crank rod extending longitudinally from the cross head finger, wherein the propeller blade crankshaft is pivotally joined to the crank rod to direct rotation of the propeller blade about the radial blade axis.

15. The gas turbine engine of claim 10 , wherein the fine stop collar first fluid passage is positioned parallel to the second fluid passage and axially separate therefrom, and wherein the OTB is translatably disposed through the fine stop collar and alternately communicable with the first fluid passage and the second fluid passage.

16. The gas turbine engine of claim 12 , wherein the at least one radial rotor hole and at least one radial stator hole have an axial range of translation between the first fluid passage and the second fluid passage, further wherein the ground-based mode of operation restricts fluid communication into the second fluid passage, and also wherein the flight based mode of operation restricts fluid communication from the first fluid passage.

17. The gas turbine engine of claim 10 , further comprising:
a coarse inlet pipe coaxially attached to the coarse rotatable pipe in fluid communication therewith;
a ground fine inlet pipe attached to the fine stop collar in fluid communication with the first fluid passage; and
a flight fine inlet pipe attached to the fine stop collar in fluid communication with the second fluid passage.

18. The gas turbine engine of claim 17 , wherein the projection of the piston defines at least one orifice through which the coarse rotatable pipe and the aft chamber are in fluid communication.

19. The gas turbine engine of claim 10 , wherein the core engine further comprises:
a compressor mounted about a static frame,
a combustor positioned downstream of the compressor to receive a compressed fluid therefrom, and
a

Assignees

• Gen Electric

Inventors

• Miszkiewicz Krzysztof

Classifications

• B64C11/306

  specially adapted for contrarotating propellers · CPC title

• F02C7/00

  Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants (controlling F02C9/00) · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title

• B64C11/38 Primary

  fluid, e.g. hydraulic · CPC title

• F02C7/06

  Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) · CPC title