VARIABLE PITCH PROPELLER ROTOR

• US 20120294718A1
• Filed: 04/27/2012
• Published: 11/22/2012
• Est. Priority Date: 05/16/2011
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: SIMMS, Paul, THORNTON, Stewart T., MCFARLANE, Colin W R
• Granted Patent: US 9,302,765 B2
• Time in Patent Office: Days
• US Class Current: 416/147
• CPC Class Codes: B64C 11/306 specially adapted for contrarotating propellers
• CPC Class Codes: B64C 11/32 mechanical
• CPC Class Codes: B64D 2027/005 Aircraft with an unducted turbofan comprising contra-rotating rotors, e.g. contra-rotating open rotors [CROR]
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A bladed rotor comprises a rotor body 2 carrying blades 6, whose pitch can be varied by means of a pitch input shaft 10. The pitch input shaft 10 drives the respective blade 6 about a spanwise axis X of the blade through a harmonic drive reduction gear 14. The harmonic drive reduction gear 14 comprises a wave generator 16 which is fixed for rotation on the pitch input shaft 10 and a flex spline which meshes with a circular spline 20 and is secured to the blade 6.

Claims

1. A variable pitch bladed rotor comprising a rotor body carrying a plurality of blades which are pivotable relatively to the rotor body about respective spanwise pitch axes, each blade being drivably coupled to a pitch control mechanism by a respective pitch input shaft which is aligned with the pitch axis and which is drivingly connected to the blade by a harmonic drive reduction gear.

2. A variable pitch propeller rotor as claimed in claim 1, in which the harmonic drive reduction gear has a flex spline secured to the blade.

3. A variable pitch propeller rotor as claimed in claim 1, in which the harmonic drive reduction gear has a circular spline fixed with respect to the rotor body.

4. A variable pitch propeller rotor as claimed in claim 3, in which each blade is pivotably mounted in a respective blade hub secured to the rotor body.

5. A variable pitch propeller rotor as claimed in claim 4, in which the circular spline is provided on the hub.

6. A variable pitch propeller rotor as claimed in claim 1, in which the harmonic drive reduction gear has a wave generator which is fixed for rotation with the pitch input shaft.

7. A gas turbine engine provided with a variable pitch bladed rotor in accordance with claim 1.

8. A gas turbine engine as claimed in claim 7, in which each pitch input shaft extends across an annular gas flow path of the gas turbine engine.

9. A gas turbine engine as claimed in claim 8, in which each pitch input shaft is accommodated within a respective sleeve extending across the gas flow path.

10. A gas turbine engine as claimed in claim 9, in which each sleeve has an aerodynamic profile.

11. A gas turbine engine as claimed in claim 7, in which the gas turbine engine is an open rotor gas turbine engine.

12. A gas turbine engine as claimed in claims 1, in which the gas turbine engine is a ducted fan engine or a turboprop engine.