Propeller assembly and pitch control unit

Patent metadata

Field	Value
Publication number	US-11519346-B2
Application number	US-202016920159-A
Country	US
Kind code	B2
Filing date	Jul 2, 2020
Priority date	Jul 4, 2019
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A variable pitch propeller assembly operatively coupled with an engine and methods for controlling the pitch of a plurality of propeller blades thereof is provided. In one example aspect, the variable pitch propeller assembly includes features for combining overspeed, feathering, and reverse functionality in a single secondary control valve. The secondary control valve is operable to selectively allow a controlled amount of hydraulic fluid to flow to or from a pitch actuation assembly such that the pitch of the propeller blades can be adjusted to operate the variable pitch propeller assembly in one of a constant speed mode, a feather mode, and a reverse mode.

First claim

What is claimed is:

1. A variable pitch propeller assembly for an engine defining an axial direction, a radial direction, and a circumferential direction, the variable pitch propeller assembly comprising:
a plurality of propeller blades rotatable about the axial direction and spaced apart along the circumferential direction, each propeller blade of the plurality of propeller blades rotatable through a plurality of blade angles about respective pitch axes each extending in the radial direction;
a pitch actuation assembly for adjusting the plurality of propeller blades through the plurality of blade angles and including a propeller dome defining a chamber; and
a pitch control unit, comprising:
at least one electrohydraulic servovalve operable to selectively allow a flow of hydraulic fluid to or from the propeller dome of the pitch actuation assembly and when hydraulic fluid is not located at an inlet port of the at least one electrohydraulic servovalve an oil starvation condition is defined; and
at least one valve selectively fluidly coupling the propeller dome to the inlet port of the at least one electrohydraulic servovalve,
wherein the at least one valve includes a one-way valve having an inlet fluidly coupled to the propeller dome and an outlet fluidly coupled to the inlet port of the at least one electrohydraulic servovalve and during the oil starvation condition the one-way valve is configured to fluidly couple the propeller dome to the inlet port of the at least one electrohydraulic servovalve.

2. The variable pitch propeller assembly of claim 1 , wherein the at least one electrohydraulic servovalve is a primary pitch control valve having a first stage and a second stage and the one-way valve is selectively fluidly coupled with the first stage.

3. The variable pitch propeller assembly of claim 1 , wherein the plurality of propeller blades move to a feather mode during the oil starvation condition at a lower speed as compared the pitch control unit without the at least one valve.

4. The variable pitch propeller assembly of claim 1 , wherein the at least one valve includes a pitch lock valve having an inlet fluidly coupled to the propeller dome and a set of outlets and during the oil starvation condition the pitch lock valve is configured to fluidly uncouple the propeller dome to the inlet port of the at least one electrohydraulic servovalve.

5. The variable pitch propeller assembly of claim 4 , wherein the at least one electrohydraulic servovalve comprises a primary control valve operable to selectively allow the flow of hydraulic fluid to or from the pitch actuation assembly and a secondary control valve adjustable between a constant speed mode, a feather mode, and a reverse mode and operable to selectively allow the flow of hydraulic fluid to or from the pitch actuation assembly based at least in part on the mode of the secondary control valve.

6. The variable pitch propeller assembly of claim 5 , wherein the set of outlets includes a first outlet fluidly coupled to a first stage of the primary control valve, a second outlet fluidly coupled to a first stage of the secondary control valve, and a third outlet fluidly coupled a drain line.

7. The variable pitch propeller assembly of claim 6 , wherein the pitch lock valve includes a valve body moveable between a first position wherein the first outlet and the second outlet are fluidly coupled with the inlet and a second position wherein the third outlet is fluidly coupled to the inlet.

8. The variable pitch propeller assembly of claim 7 , wherein the valve body is configured to be moveable from the first position to the second position based on a decrease in internal pressure caused during the oil starvation condition.

9. The variable pitch propeller assembly of claim 6 , further comprising a solenoid valve fluidly coupled between the third outlet and the drain line and operable to selectively open and close a flow of hydraulic fluid through the drain line.

10. The variable pitch propeller assembly of claim 9 , wherein the solenoid valve is one of user actuated or automatically controller actuated.

11. The variable pitch propeller assembly of claim 9 , wherein actuation of the solenoid valve opens the flow of hydraulic fluid through the drain line.

12. The variable pitch propeller assembly of claim 5 , wherein the secondary control valve includes a valve body defining a chamber and a spool movable within the chamber and where the spool defines a first groove and a second groove, and wherein the primary control valve is fluidly connected with the first groove when the spool is in at least one constant speed position or in at least one reverse position.

13. The variable pitch propeller assembly of claim 5 , wherein the pitch actuation assembly further comprises:
a control piston translatable within the propeller dome;
a piston rod connected to the control piston and extending into a propeller gear box of the engine, the piston rod translatable in unison with the control piston;
an oil transfer bearing surrounding the piston rod within the propeller gear box of the engine and defining a flight gallery fluidly connected with the secondary control valve and a ground gallery fluidly connected with the secondary control valve; and
a beta tube enclosed within the piston rod and fluidly connecting the flight gallery with the chamber of the propeller dome.

14. The variable pitch propeller assembly of claim 13 , wherein a flight gallery conduit fluidly connects the secondary control valve with the flight gallery and a ground gallery conduit fluidly connects the secondary control valve with the ground gallery.

15. A method for controlling a variable pitch propeller assembly driven by a powerplant, the powerplant defining an axial direction and a radial direction and comprising a controller, the variable pitch propeller assembly having a plurality of propeller blades rotatable about the axial direction and adjustable about respective pitch axes each extending along the radial direction, a propeller control system comprising a pitch actuation assembly for actuating the propeller blades about their respective pitch axes and a pitch control unit for driving the pitch actuation assembly and comprising a primary control valve and a secondary control valve both communicatively coupled with the controller, the primary control valve and the secondary control valve each configured to selectively control a flow of hydraulic fluid to or from the pitch actuation assembly, the method comprising:
operating the powerplant;
controlling, by the controller, the secondary control valve adjustable between a constant speed mode, a feather mode, and a reverse mode to selectively allow a controlled amount of hydraulic fluid to or from the pitch actuation assembly; and
selectively diverting, during an oil starvation condition, hydraulic fluid from a propeller dome of the variable pitch propeller assembly via at least one valve,
wherein the at least one valve includes a one-way valve having an inlet fluidly coupled to the propeller dome and an outlet fluidly coupled to an inlet port of the primary control valve and during the oil starvation condition the one-way valve provides fluidly coupling from the propeller dome to the inlet port of the primary control valve.

16. The method of claim 15 , further comprising controlling a feathering with the primary control valve upon a failure of the secondary control valve.

17. The method of claim 15 , wherein the at least one valve includes a pitch lock valve having an inlet fluidly coupled to the propeller dome, a first

Assignees

• Ge Aviation Czech S R O
• Ge Avio Srl

Inventors

• Cervelli Giuseppe
• Castellani Simone
• Manzoni Miriam
• Bellocchio Giuseppe
• Jirasek Vojtech

Classifications

• B64C11/40

  automatic · CPC title

• B64C11/38 Primary

  fluid, e.g. hydraulic · CPC title

• B63H3/10

  characterised by having pitch control conjoint with propulsion plant control · CPC title

• B64C11/385

  comprising feathering, braking or stopping systems · CPC title

• Y02T50/60

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