US 4,927,329 AGranted

Aircraft engine unducted fan blade pitch control system

AssigneeGeneral Electric Company

InventorsGerald B. Kliman, Donald W. Jones

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Abstract

An electric motor driven blade pitch varying system for the fan blades of an unducted fan type aircraft gas turbine engine utilizes permanent magnet alternating current motors located in the oil sump region of the engine. An alternator driven by the engine generates unregulated variable frequency, variable amplitude power which is rectified and placed on a DC bus. Controlled inverters convert the DC power on the bus to appropriate AC power for the motors. The system incorporates redundancy without significant weight penalty by providing alternators and motors dividing into two independent operating sections on common shafts. Separate electronic circuits are provided to supply power for each sectionalized motor or to rectify power from each alternator section. A common power bus may be used to couple the multiple motors and alternators. The common bus may alternatively receive power from tbe aircraft 400 Hz system or from on-board batteries.

Claims19

Dependent claims

Aircraft propulsion apparatus, comprising:

(a) a gas generator for generating a gas stream and containing therein compressor means for driving a rotatable shaft;
(b) first and second coaxially situated rotatable members;
(c) a plurality of first and second rotor blades affixed to said first and second rotatable members, respectively, said first and second rotor blades being positioned such that a gas stream, when produced by said gas generator, impinges thereon and causes said first and said second rotatable members to counterrotate;
(d) a plurality of forward and aft variable pitch propulsor blades coupled to, and extending radially outwardly of, said first and second rotatable members, respectively;
(e) gear means coupled to said propulsor blades;
(f) electric motor means, including rotor means, mounted in stationary fashion relative to said rotatable members;
(g) means coupling said rotor means to said gear means such that rotation of said rotor means effects a pitch change of said propulsor blades;
(h) electrical generator means coupled to said rotatable shaft for generating electrical power;
and
(i) circuit means coupling said electrical generator means to said motor means, said circuit means including control means responsive to a desired propulsor blade pitch command for controlling said motor means to force each of said blades to a respective desired blade pitch.

7 more elements

In a propulsion system for an aircraft, first and second engines mounted to said aircraft, each of said engines, respectively, including a rotatable structure, an annular gas flowpath extending coaxially with said rotatable structure, a plurality of rotor blades coupled to said rotatable structure and extending into said gas flowpath such that a gas stream through said flowpath causes said rotatable structure to rotate, and a plurality of variable pitch propulsor blades coupled to and disposed radially outward of said rotatable structure, control means for controlling blade pitch of the propulsor blades driven by said first and second engines, said control means comprising:

(a) first and second alternators coupled in driven relationship with said first and second engines for supplying variable frequency, variable amplitude electric power;
(b) first and second electric power busses;
(c) first and second rectifiers interconnecting said first and second alternators, respectively, and said first power bus, said first and second rectifiers, respectively, converting the variable frequency, variable amplitude electric power from said first and second alternators, respectively, to DC power on said first bus;
(d) third and fourth rectifiers interconnecting said first and second alternators, respectively, and said second power bus, said third and fourth rectifiers, respectively, converting the variable frequency, variable amplitude electric power from said first and second alternators, respectively, to DC power on said second bus;
(e) first and second electric motors mounted in stationary fashion relative to said rotatable structure of said first engine, each of said first and second motors, respectively, having a rotatable shaft extending therefrom, respectively;
(f) third and fourth electric motors mounted in stationary fashion relative to said rotatable structure of said second engine, each of said third and fourth motors, respectively, having a rotatable shaft extending therefrom, respectively;
(g) first and second inverters coupling said first and second motors, respectively, to said first power bus for converting DC power on said first bus to controllable amplitude AC power for driving said first and second motors, respectively;
(h) third and fourth inverters coupling said third and fourth motors, respectively, to said second power bus for converting DC power on said second bus to controllable amplitude AC power for driving said third and fourth motors, respectively;
(i) first and second gear means interconnecting the shafts extending from said first and second motors, respectively, and said first plurality of propulsor blades for driving propulsor blades of said first engine to selected pitch positions;
and
(j) third and fourth gear means interconnecting the shafts extending from said third and fourth motors, respectively, and said second plurality of propulsor blades for driving the propulsor blades of said second engine to selected pitch positions.

8 more elements

Dependencies are inferred from the claim text.