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US 5,205,712 AGranted
Variable pitch fan gas turbine engine
AssigneeAllied-Signal Inc.
InventorPaul U. Hamilton
Life of this patent
Estimating the term…
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AssigneeAllied-Signal Inc.
InventorPaul U. Hamilton
Estimating the term…
A gas turbine engine for aircraft propulsion includes a variable pitch fan, pitch change of which is effected by providing a small D.C. excitation current to a selected one of two non-rotating field coils dependent upon the direction of pitch change desired. The field coils each form the static part of respective polyphase A.C. alternators, and the rotating armatures of the alternators connect to respective separate stator windings of a compound polyphase A.C. reversible induction motor rotating with the fan. An armature of the motor is relatively rotatable and couples with the fan blades to pivotally vary their pitch angle. An A.C. current is available from the non-excited alternator field coil, and may be rectified and controlled for use as the D.C. excitation current. Thus, all energy requirements of the pitch change apparatus may be extracted from the rotor of the fan engine.
Pitch change apparatus for a variable-pitch fan of a fan propulsion turbine engine, said pitch change apparatus comprising a first and second axially spaced alternator, each alternator having a stator carried by a housing of said engine and a rotor rotated by a rotatable portion of said engine, a motor axially spaced from said alternators and receiving excitation current from a selected one of said alternators, said motor including an annular stator rotated by said engine rotatable portion, and an annular motor armature rotatable relative to said engine rotatable portion, speed reduction means, carried by said rotatable engine portion, having an input rotated by said motor armature and an output rotatably driving a torque output member independently rotatably carried by said engine rotatable portion, and linkage means coupling said torque output member with fan blades of said fan to alter the pitch angle thereof in response to rotation of said torque output member.
The apparatus of claim 5 wherein said two separate stator windings define a mutual inductance therebetween, whereby polyphase A.C. current applied to one of said stator windings induces a polyphase A.C. current in the other of said two stator windings.
A propulsion turbine engine having a nonrotational housing journaling a rotational engine rotor thereon, a propulsion thrust fan driven by said turbine engine including a circumferentially arrayed plurality of fan blades pivotally movable about respective radial axes, and apparatus for selectively pivoting said fan blades, said apparatus comprising:
Dependencies are inferred from the claim text.