# US 2014/0193261 A1 · Hydraulic system for controlling the orientation of fan blades

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- Number: US 2014/0193261 A1
- Document ID: US20140193261A1
- Status: Published application
- Kind: A1
- Application number: 14/237,753
- Filed: 2012-08-03
- Published: 2014-07-10
- Earliest claimed: 2011-08-08
- Assignees: Snecma
- Inventors: Caroline Frantz; Regis Michel, Paul Deldalle
- Web page: https://patentgrep.com/patent/US20140193261A1

## CPC

- B64C 11/38: fluid, e.g. hydraulic
- B64C 11/303: {characterised by comprising a governor}
- B64C 11/308: {automatic}
- B64C 11/42: non-automatic
- F01D 7/00: Rotors with blades adjustable in operation; Control thereof (for reversing F01D1/30)
- F02K 3/025: {the by-pass flow being at least partly used to create an independent thrust component}
- B64D 2027/005: {Aircraft with an unducted turbofan comprising contra-rotating rotors, e.g. contra-rotating open rotors [CROR]}
- F05D 2220/324: to drive unshrouded, low solidity propeller
- F05D 2220/325: to drive unshrouded, high solidity propeller
- F05D 2220/36: specially adapted for the fan of turbofan engines
- F05D 2260/79: Bearing, support or actuation arrangements therefor
- F05D 2270/64: Hydraulic actuators
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- B64C: AEROPLANES; HELICOPTERS
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A hydraulic system for controlling orientation of fan blades in a turbine engine including at least one set of adjustable pitch fan blades actuated by actuators that are connected to a hydraulic pump, and a small pitch protection valve controlled by an associated solenoid valve to make it possible on the ground, when the orientation of the blades is substantially perpendicular to the axis of the turbine engine, to pass from a first operating zone in which a speed of pitch variation of the blades is low to a second operating zone in which a speed of pitch variation is considerably higher, wherein operating pressure of the hydraulic pump is controlled by the solenoid valve controlling the small pitch protection valve to define two outlet levels corresponding to the two operating zones.

## Claims

### Claim at position 1

1-7. (canceled)

### Claim 8

A hydraulic system for controlling orientation of fan blades in a turbine engine comprising:
at least one set of adjustable pitch fan blades actuated by actuators that are connected to a hydraulic pump; and
a small pitch protection valve controlled by an associated solenoid valve to make it possible on the ground, when the orientation of the blades is substantially perpendicular to the axis of the turbine engine, to pass from a first operating zone in which a speed of pitch variation of the blades is low to a second operating zone in which the speed of pitch variation is considerably higher,
wherein operating pressure of the hydraulic pump is controlled by the solenoid valve controlling the small pitch protection valve to define two outlet levels corresponding to the two operating zones.

### Claim 9 (depends on 8)

A system according to claim 8, wherein the hydraulic pump is an axial piston pump.

### Claim 10 (depends on 9)

A system according to claim 9, further comprising a bypass duct between an inlet of the solenoid valve and a control inlet of the axial piston pump.

### Claim 11 (depends on 10)

A system according to claim 10, further comprising a diaphragm mounted in a low-pressure return line of the axial piston pump and a diaphragm mounted in a high-pressure feed line connecting the axial piston pump to the solenoid valve.

### Claim 12 (depends on 9)

A system according to claim 9, further comprising a bypass duct between an outlet of the solenoid valve and a control inlet of the axial piston pump.

### Claim 13 (depends on 11)

A system according to claim 11, further comprising a diaphragm mounted in the high-pressure feed line connecting the axial piston pump to the solenoid valve.

### Claim 14 (depends on 8)

A two-propeller turboprop comprising a hydraulic system for controlling orientation of fan blades according to claim 8.